Responsive frame

[Dieter Britz]

I hear and read mention of a "responsive frame". What does
this mean, and what kind of frame is responsive, and not?

--
Dieter Britz

[Tom Kunich]

On Friday, March 4, 2022 at 6:49:27 AM UTC-8, Dieter Britz wrote:
> I hear and read mention of a "responsive frame". What does
> this mean, and what kind of frame is responsive, and not?

Dieter, this is one of those terms that is invented to mean nearly anything. Originally it meant the bike was responsive to lean and fork motion but it soon became an advertising term that means little if anything. Responsiveness as I've learned to my dismay is a combination of many things from the flexibility of the frame to the tire size and pressure. On a steep descent I discovered that my Colnago C40, because of the flexibility of the frame would steer itself. This was a bike very often described as responsive. This sort of self-steering over the years was worked out of steel frame with ultra-stiff steel tubing such as oversize and triple butting etc. But responsiveness is a product of the fork flex and tire/wheel give. So unless the frame is very flexible such as the C40, it has very little influence. And ultra stiff plastic structures can slowly break themselves up.

So I always remember that although they are not supposed to, Carbon fiber frames have a finite lifespan whereas aluminum which is known to have a fatigue life rarely fail. The lifespan of a new steel frame such as a Waterford Racing, has essentially an unlimited lifespan and weighs close to aluminum But this means that the workmanship is very important.

So saying a bike is responsive means almost but not quite nothing.

[AMuzi]

On 3/4/2022 8:49 AM, Dieter Britz wrote:
> I hear and read mention of a "responsive frame". What does
> this mean, and what kind of frame is responsive, and not?
>

It's a marketing term, unrelated to quantifiable values.

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

[Roger Merriman]

Dieter Britz <dieterh...@gmail.com> wrote:
> I hear and read mention of a "responsive frame". What does
> this mean, and what kind of frame is responsive, and not?
>

As others have said a fair bit of marketing fluff, this said at the
extremes bike with sharp geometry vs slack will have quicker steering.

In terms of weight and frame stiffness, only at the extremes really!

Roger Merriman

[Andre Jute]

I've read the other responses and had a good chuckle.
>
Sure, marketing. But incompetent marketing, in that the subtext to me is a marketing ignoramus trying to cover up the fact that the frame is limp, and its flex will steer the bike without input from the rider, usually off the road.
>
A truly responsive bike is a tautology, because any bike with a stiff enough frame can be made quicker reacting (same thing as the now discredited "responsive") by the correct geometry, which, as Roger says, generally means steeper head angles, plus reworking the fork.
>
But I don't know why a commuter or a shopper or a social or health rider or anyone who isn't a racer would want a very quick-reacting bike. In my motor racing days, from which most people remember only that I sold a hemihead design to Chrysler, in fact I was a chassis and suspension specialist. Back then I would have said, cuttingly, "Don't give me this marketing crap about quick reactions. What you mean is that've you've bodged up an oversteering frame, dangerous in most hands." Apparently we have an example belonging to a forum member in Tom's Colnago.
>
For those who don't have the background and the experience, a neutral-steering bike could also be described as being lethally unpredictable because you'll never know whether it will put you in the ditch or under the onrushing truck until you're there already. Zero utility.
>
My own bikes are all set up to understeer. The consequential predictability and stability of line almost regardless of road surface makes the essential difference on downhill descents at speed on bad roads when I'm leaving the road racers behind with white brackets of fear beside their lips.
>
Much more at "In praise of riding low pressure tyres fast" if you haven't seen it yet:
http://thorncyclesforum.co.uk/index.php?topic=3798.msg16360#msg16360
It's worth reading the entire thread for the thoughtful additions and useful links by other cyclists.
>
Andre Jute
Ah, them were the days!
>

[Dieter Britz]

On Sat, 05 Mar 2022 02:50:18 -0800, Andre Jute wrote:
[...]

> My own bikes are all set up to understeer. The consequential
> predictability and stability of line almost regardless of road surface
> makes the essential difference on downhill descents at speed on bad
> roads when I'm leaving the road racers behind with white brackets of
> fear beside their lips.

[...]

> Andre Jute Ah, them were the days!

How do you set a bike up for understeer? I don't know what under-
or oversteer means.

--
Dieter Britz

[sms]

Change the length of the stem.

Marshall “Major” Taylor apparently won a lot of races due to his
sliding, adjustable-length, stem. I don't think that there's any such
animal still available (though adjustable stems that simultaneously
change the height and reach are available so you could get the same
effect if the height of the stem on the steer tube is also adjustable.

One company did introduce a sliding, adjustable-length stem, but not
sure if it made it to market:
<https://bikerumor.com/just-going-to-drop-this-right-here-3fstech-slams-that-stem-with-aim-dropper-stem/>.

[AMuzi]

Standard front geometry should be neutral[1] and designers
know the system well.
https://dclxvi.org/chunk/tech/trail/image/trail.jpg

In that case, when turning the wheel side to side, the frame
will neither rise nor fall.

In an understeer design like this:
http://www.yellowjersey.org/gcdl1.html

The frame rises when the handlebar is turned, which is to
say the bicycle travel in a straight path unless coerced
otherwise. This may be desired for unpaved roads and/or
heavy cargo loads. Put another way, the rider/bicycle/cargo
weight must be lifted to turn the handlebar.

The inverse, oversteer, makes a bicycle less stable (='more
responsive') and rider effort is needed to keep it in a
straight path. When the fork turns, the frame falls:
http://1.bp.blogspot.com/-WJp92Vd-dMI/TtlTUAlSArI/AAAAAAAADLE/WmujhKVkXGg/s1600/sanrensho2.jpg

[1] Riders request variations and designers create specialty
vehicles but neutral is the standard.

[AMuzi]

On 3/5/2022 9:38 AM, sms wrote:
> On 3/5/2022 7:11 AM, Dieter Britz wrote:
>> On Sat, 05 Mar 2022 02:50:18 -0800, Andre Jute wrote:
>> [...]
>>> My own bikes are all set up to understeer. The consequential
>>> predictability and stability of line almost regardless of
>>> road surface
>>> makes the essential difference on downhill descents at
>>> speed on bad
>>> roads when I'm leaving the road racers behind with white
>>> brackets of
>>> fear beside their lips.
>> [...]
>>> Andre Jute Ah, them were the days!
>>
>> How do you set a bike up for understeer? I don't know what
>> under-
>> or oversteer means.
>
> Change the length of the stem.
>

> Marshall “Major†Taylor apparently won a lot of races

> due to his sliding, adjustable-length, stem. I don't think
> that there's any such animal still available (though
> adjustable stems that simultaneously change the height and
> reach are available so you could get the same effect if the
> height of the stem on the steer tube is also adjustable.
>
> One company did introduce a sliding, adjustable-length stem,
> but not sure if it made it to market:
> <https://bikerumor.com/just-going-to-drop-this-right-here-3fstech-slams-that-stem-with-aim-dropper-stem/>.
>
>

There are more adjustable track stems than there are
customers for adjustable track stems:

https://farm2.static.flickr.com/1091/1388506099_1fbe0f3e6c.jpg

https://4.bp.blogspot.com/-kMkQ0P8YqAI/VGTzbaPhhyI/AAAAAAAAMJw/TqGkUescR9I/s1600/IMG_9582.JPG

https://cicli-berlinetta.com/wp-content/uploads/2021/02/3TTT-Silver-4.jpg

https://velobase.com/CompImages/Stems/F8626E1F-2BED-4340-BFCE-D48BBB83D3F8.jpeg

https://lh3.googleusercontent.com/-FriYEkikkYI/TX_vylsFc6I/AAAAAAAAAE8/q6xUQCsI7b0/s1600/DSC09995.JPG

Five examples from four countries.

[sms]

On 3/5/2022 8:08 AM, AMuzi wrote:

<snip>

> There are more adjustable track stems than there are customers for
> adjustable track stems:
>
> https://farm2.static.flickr.com/1091/1388506099_1fbe0f3e6c.jpg
> https://4.bp.blogspot.com/-kMkQ0P8YqAI/VGTzbaPhhyI/AAAAAAAAMJw/TqGkUescR9I/s1600/IMG_9582.JPG

> https://cicli-berlinetta.com/wp-content/uploads/2021/02/3TTTilver-4.jpg

> https://velobase.com/CompImages/Stems/F8626E1F-2BED-4340-BFCE-D48BBB83D3F8.jpeg
> https://lh3.googleusercontent.com/-FriYEkikkYI/TX_vylsFc6I/AAAAAAAAAE8/q6xUQCsI7b0/s1600/DSC09995.JPG
> Five examples from four countries.

Those are all quill stems for threaded headsets

For threadless, I could not find anything other than the one I provided
the link to.

[Frank Krygowski]

Sorry, I think "the frame will neither rise nor fall" is incorrect. If
the front end geometry generates any "trail" at all, the frame must fall.

Look at http://www.yellowjersey.org/gcdl1.html again. Draw a line
representing the steering axis down to the ground. Next, draw a line
from the tire contact point directly to (and perpendicular to) the
steering axis. I suppose we could call that the 'lever arm' of the
contact point.

That 'lever arm' slants upwards from the contact point to the steering
axis. If you 'swing' it to the side by turning the handlebars, it rises
relative to the bike. IOW, if you clamped the top tube in a fixed
position and height, the 'swing' would cause the contact point to rise.
Or, switching reference frames, if you leave the tire normally on the
ground, the frame will fall.

I don't have a bike with a head angle as slack as the black one in the
photo, but I just measured my touring bike. As with every other bike
I've checked, turning the bars causes the frame to drop a bit.

See "Wheel Flop" at
https://cyclingtips.com/2018/11/the-geometry-of-bike-handling-its-all-about-the-steering/

"Wheel flop is similar to trail in that it is determined by the
combination of head tube angle and fork rake, however it is concerned
with how the position of the front axle changes as the handlebars are
turned. In almost all instances, the height of the front axle is lowered
when this happens"

--
- Frank Krygowski

[AMuzi]

On 3/5/2022 12:25 PM, Frank Krygowski wrote:
> On 3/5/2022 11:02 AM, AMuzi wrote:
>> On 3/5/2022 9:11 AM, Dieter Britz wrote:
>>> On Sat, 05 Mar 2022 02:50:18 -0800, Andre Jute wrote:
>>> [...]
>>>> My own bikes are all set up to understeer. The
>>>> consequential
>>>> predictability and stability of line almost regardless
>>>> of road surface

>>>> makes the essential difference on downhill descents at

You have a few bicycles handy. Try turning the handlebars
while observing the front end of the frame. Your bicycles
should all be pretty close to zero height change, maybe a
millimeter or two, nothing significant.

[AMuzi]

On 3/5/2022 12:25 PM, Frank Krygowski wrote:

> On 3/5/2022 11:02 AM, AMuzi wrote:
>> On 3/5/2022 9:11 AM, Dieter Britz wrote:
>>> On Sat, 05 Mar 2022 02:50:18 -0800, Andre Jute wrote:
>>> [...]
>>>> My own bikes are all set up to understeer. The
>>>> consequential
>>>> predictability and stability of line almost regardless
>>>> of road surface

>>>> makes the essential difference on downhill descents at

Experiment report:

Using a four-foot aluminum level I put one end on a table
and the other end on the front of the top tube of a medium
(56cm) Gunnar Road with Michelin 23 tires. Turning the
handlebar, I observe the bubble doesn't move.

[Tom Kunich]

Those adjustable stems used to be handy for initial setup of the bike. Not much else otherwise

[Tom Kunich]

Using a 4 foot bubble level on my Trek Alpha also shows no motion at all of the bubble.

[John B.]

Is this term under/over steer as used for bicycles have the same
meaning that it does for motorcycles and autos? Which usually means
that the vehicle does not follow the curved path that the front
wheel(s) does. Example of extreme oversteer:
https://www.youtube.com/watch?v=acA_mGWbLOQ
--
Cheers,

John B.

[Frank Krygowski]

OK, help me understand.

Again, ISTM that if we marked the tire-to road contact point with chalk,
then rotated the bars 360 degrees, that chalked point would describe a
circle. The circle would be inclined to horizontal by (90 - head tube
angle), with its high point directly forward. The marked point on the
tire would be farthest below the head tube's height with the bars
straight ahead. It would get closer to the head tube (or IOW the head
tube would drop) at any other steering angle.

Is there some other factor I'm not visualizing that would apply a
contrary action, to cancel out this effect? So far I can't think of one.

I checked my Cannondale again. I held a meter stick vertically, using my
fingers to pinch it to the top tube. I can easily feel the relative
motion. At a 45 degree steering angle (admittedly, used only for
balancing at super slow speeds) it seems the frame drops between one and
tow millimeters. At lesser steering angles the motion is almost
imperceptible, but as I visualize the geometry, it seems it must be there.

One thing I just noticed: The tire contact point actually changes as the
steering angle increases. Judging by the spokes' position, at 45 degrees
steering, the contact point has moved forward about 10 degrees. Does
this somehow affect things?

--
- Frank Krygowski

[Andre Jute]

Actually, there's one exception to this rule. Royal Dutch Gazelle offers an OEM proprietary stem on many of their bikes, IIRC called the Switch. Whatever it is called, it is a toollessly adjustable stem. You flip up the lever and then you can raise or lower the stem on the pivot at the steerer tube end, and rotate the handlebars within their clasp at the front end. I used this stem which came on my Gazelle Toulouse, a Dutch stadssportief- or vakansie-fiets, basically a well trimmed commuter with North Road bars, to set a ***truck-assisted*** personal ton-up record, turning the swivel down and then rotating the handlebars so that the grips pointed almost vertically to the road, to get the most aerodynamic posture possible on the bike. Took about five minutes because some of the cabling had to be adjusted. Another five minutes after I set the record to restore the bike to its respectable commuter image. Pic of the bike in question about halfway down the page here:
http://coolmainpress.com/BICYCLINGgazelletoulouse.html
About twenty years ago I tried to buy one of these the magic stems for another bike and discovered they come only for 1in quill stems.

Andre Jute
*** For the morons who take personal umbrage when I leave this off and then cause months and years of unpleasantness for everyone when I drop-kick them over the houses for their arrogance -- shame on you jerks.

[Andre Jute]

You've already had some good answers here, Dieter. Even Scharfie managed to get a technicality right: you can make the bike less reactive by simply fitting a wider handlebar so that the same distance of hand movement on the wide bar as compared to the narrower bar creates a smaller input at the contact patch. But that's mickey mouse stuff, finishing-up details for those who have to take whatever frame a manufacturer offers, and who perhaps made the wrong choice, or who are gimmicking a best available compromise right.

Ideally, starting from the drawing board, a faster-reacting bike has a steeper geometry, say a head tube angle of 72 degrees, and an understeering bike will have more laid-back angle of say 68 degrees. Andrew Muzi published photos of these two bikes. If you draw these these head angles out and then put a fork with the same offset on each, you will discover that the head angle, which is also the fork angle (so obvious that we normally don't say it), influences the trail of the front wheel. The trail is the distance between a perpendicular line running from the road surface to the wheel centre and the projection of the fork angle to the ground (if, as is true in the majority of cases, the fork shaft is straight and the fork blades continue that line until their lower-end curve starts). It should be obvious to you now that different trail distances are required for the different concepts, fast-reacting and stable (small amount of understeer).

At this point you can further influence the steering by changing forks with various amounts of offset and thus different amounts of trail which in turn give different ratios of effect to steering inputs.

Let us consider a bike and frame you bought as a set, and for one reason or another cannot change. What can you do to influence the handling? For a start, you could possibly bend the forks to change the trail, but on anything but mild steel you're just looking for trouble doing so; I imagine a responsible LBS will refuse to help you. But sometimes you can spread forks, especially in steel, a few millimeters, so you can fit fatter tyres, which by themselves will give you more stable handling by generally raising the bike so that the trail is longer. Draw it out. You'll be amazed. Narrower tyres will shorten the trail by dropping the bike a few millimeters and quicken the response. This effect, either way, is magnified by more or less rubber being in contact with the road, so that there is more or less friction to be overcome by steering inputs. Next, try changing the pressure in your tyres: the max on the sidewall is not a recommendation but an outer limit for the thoughtless. In ten years of riding 60mm Schwalbe Big Apples at pressures of 2 bar and replenished once a month when it had fallen to 1.6 or 1.5 bar, I had two snakebite punctures, one my fault for crashing through a new pothole at over 50kph, the other picked up on a building site where I was consulting the guy who operated the cordless angle grinder on how long it would take to grind through an arm of my best quality Abus D-lock. I could make even those Big Apples react faster by going to 3 bar but then they would be less stable on rough roads and bloody uncomfortable all the time, because they're the bike's main suspension: it would be a waste of expensive tyres, and the cornering power of my low inflation regime, very important on the small lanes that wander downhill through the fields, would just be gone. Notice the interplay between understeer, fat tyres, low pressure and speed and cornering power. I assume that you know the Utopia Kranich I ride has a very long wheelbase -- my bike is over two meters long, another factor in slowing the response to steering inputs in order to enhance stability.

Okay, now what is all this stability for? Or alternatively, how much of it do we want? Quite frankly, my bike, which for such a large bike is actually a lightweight (specially drawn Columbus tubes) and is made heavy only by fitting the biggest and strongest of everything, plus an electric motor and a humongous battery, and normally carrying heavy painting gear in the pannier basket, at slow speed has heavy steering. I could tune it to be lighter at walking speed but won't because the motor has a walking speed setting which rolls the bike and the steering instantly lightens up, and once you're going even a handful of clicks per hour, the steering is light, until at high speed it is very light, just heavy enough to give me some road feel. I also have 620mm wide North Road bars so that making small smooth inputs doesn't take any concentration.

I drove Porsche until I was almost middle-aged, but I drove a Porsche across Europe, from Cambridge in the English Fens to Nardo in the boot of Italy where I was testing, just once, when the air traffic controller's strike coincided with my trans-continental car, a Bentley Turbo, being in pieces while I fitted a limited slip diff. It was just too much of a pain paying constant attention to the wretched little buzzbomb's infernal tendency to head for the wall or the ditch for that far when I could set the same averages in a comfortable family saloon. I take the same attitude to bicycles.

All these small changes on an existing frame and fork I'm talking about add up cumulatively. You'll know when you've gone too far to one side or the other when your oversteering bike falls over its own front wheel and gives you a face-plant, or when your understeering bike requires too much input from you to make a fast curve -- notice that with the stable bike nothing too bad happens to you, though you might get wet in the ditch.

As for Andrew's joke about a neutral-steering bike, the example he shows would very likely be as nervous as a quarterhorse stallion, and as likely to throw you off. There's no such thing as neutral steering, either in cars or in bikes*; "neutral" is just a marketing euphemism for "bad understeer, plant you on your face at first opportunity, throw you under truck at next opportunity".

One more thing. You could possibly grade a bike for under- or over-steer by placing a scale on the contact patch under the tyre, and measuring the rise and fall caused by the handlebars converted to weight. The oversteering bike will become lighter, the understeering bike resists inputs by becoming heavier, pushing into the road for more friction. If you want to measure distance instead, you'll still need the scale for conversion to pounds/feet or whatever unit you prefer; the edge of the rim is a good place to make measurements with your wife's dress-hemming measure or the spike that comes out of a vernier caliper for depth measurements.

If you have any further questions, ask.

Andre Jute
* I wish Jobst were here to think through this sort of thing for us.

[AMuzi]

On 3/5/2022 8:45 PM, Frank Krygowski wrote:
> On 3/5/2022 2:25 PM, AMuzi wrote:
>> On 3/5/2022 12:25 PM, Frank Krygowski wrote:
>>> On 3/5/2022 11:02 AM, AMuzi wrote:
>>>> On 3/5/2022 9:11 AM, Dieter Britz wrote:
>>>>> On Sat, 05 Mar 2022 02:50:18 -0800, Andre Jute wrote:
>>>>> [...]
>>>>>> My own bikes are all set up to understeer. The
>>>>>> consequential
>>>>>> predictability and stability of line almost regardless
>>>>>> of road surface

>>>>>> makes the essential difference on downhill

On a 360-degree fork turn I have no idea but you're probably
right. For normal range, as you note 45 deg left or right,
any height change is between zero and negligible.

Crashed frames with damaged forks and changed head angles
exhibit wild changes, as do specialty machines designed for
over- or under- steer effect.

[AMuzi]

There's more than head angle and rake.

Fork height and tire width directly change trail. Weight
distribution is another not always considered effect.

[Sir Ridesalot]

I have a red Bianchi that was given to me as a frameset because the owner ran into a parked car and bent the downtube and the headtube a bit. Just for fun I built the frameset up with some spare components I had lying around. I took it out to a parking lot to try riding it and I was amazed at how well it tracked and how easy it was to ride no hands. I liked the ride so much t hat I'm restoring it back to its original Suntour Cyclone components.

Cheers

[AMuzi]

On 3/6/2022 11:10 AM, Sir Ridesalot wrote:
> On Sunday, March 6, 2022 at 10:58:17 a.m. UTC-5, AMuzi wrote:
>> On 3/5/2022 8:45 PM, Frank Krygowski wrote:
>>> On 3/5/2022 2:25 PM, AMuzi wrote:
>>>> On 3/5/2022 12:25 PM, Frank Krygowski wrote:
>>>>> On 3/5/2022 11:02 AM, AMuzi wrote:
>>>>>> On 3/5/2022 9:11 AM, Dieter Britz wrote:
>>>>>>> On Sat, 05 Mar 2022 02:50:18 -0800, Andre Jute wrote:
>>>>>>> [...]
>>>>>>>> My own bikes are all set up to understeer. The
>>>>>>>> consequential
>>>>>>>> predictability and stability of line almost regardless
>>>>>>>> of road surface

>>>>>>>> makes the essential difference on downhill

> I have a red Bianchi that was given to me as a frameset because the owner ran into a parked car and bent the downtube and the headtube a bit. Just for fun I built the frameset up with some spare components I had lying around. I took it out to a parking lot to try riding it and I was amazed at how well it tracked and how easy it was to ride no hands. I liked the ride so much t hat I'm restoring it back to its original Suntour Cyclone components.
>
> Cheers
>

A 'field enhancement' of Bianchi's design!
A few minutes with a protractor, tape measure and a similar
road bicycle might show you why.

[Andre Jute]

Quite so. That's why I laid emphasis on tyre changes, because they're one of the easiest ways for the cyclist to change the handling of his bike. As for weight distribution, on the antisocial media one can't go on at the exhaustive length possible in a lecture hall or a tutorial room with a few favored students*, and one naturally assumes that an adult cyclist has the common sense not to distribute weight on the bike dangerously.

Actually the most important thing I didn't say outright, though it is implied in "cumulative", is that a bicycle suspension and steering is a matter of additive subtleties, not all of which are well understood. For instance, a known unknown, not solved in roundabout three-quarters of a century, is why a reversed fork doesn't interfere terminally with the bike's steering.

Andre Jute
* But not necessarily in books which can only be a commercial length. When my DESIGNING AND BUILDING SPECIAL CARS was published Arthur Mallock, the late Major, the most influential British designer and manufacturer of racing cars for club racers, called me to say, "Your publisher should have allowed you at least half that many pages again. You'll just have to write another book, old boy." The Major is another we could have done with in this thread, as he knew everything there is to know about suspension jacking and corner weights.
>

[Frank Krygowski]

I just did more geometry work. For now, I'm treating the front wheel as
a pure circle, i.e. a disc of zero thickness, or a tire of zero width.
(I'm not sure what difference tire width will make, if any.)

You're certainly right that the height change is small, at least for
small steering angles. The obvious limit is zero height change for zero
steering angle. But ISTM that as steering angle increases from zero,
there must be _some_ drop in frame height. Here's some of the geometry.

The contact point of the tire on the road occurs at the back of the
"trail," and the trail value is often easy to look up for a given bike.
Alternately it's easy to calculate from head angle H and fork offset.

Let's call the trail value T.

Spinning the fork all the way around makes the contact point trace a
circle. Its radius is R=T*cos(90-H) and that circle tilts upward 90-H
degrees. That upward tilt is the basis of what I've been saying.

Steering angle S causes the contact point to swing a bit upward along
that circle. I'll give details if desired, but using two projected views
and some fairly simple trig, the change in height as that contact point
swings up (i.e. closer to the top tube) is the amount the frame drops.
Call it D.

I get D = R * (1-cos (S)) * sin(90-H)
or
D = T * cos(90-H) * (1-cos (S)) * sin(90-H)

As I see it, for any conventional bike this is going to cause the frame
height to drop just a bit. It's not much, because the circle tilts up
only about 17 or 18 degrees, and for most riding S is small. But it must
be there.

Plugging in an extreme steering angle of 45 degrees with a 73 degree
head angle and 60 mm trail, this gives a drop of 4.91mm. Plugging in the
same values but with a more typical 10 degree steering angle gives a
drop of 0.25mm which is small indeed, but not zero. (The controlling
term is (1 - cos(S)), which is very small for normal steering angles.)

BTW, I just held the meter stick against the top tube of my ancient
Raleigh commuter/grocery bike. It too exhibited a drop as I turned the
handlebars. It's almost undetectable for small steering angles, but it's
there. It doesn't seem to be as large as 5mm, but then I don't know the
bike's head angle or trail. (Yet.)


--
- Frank Krygowski

[Andre Jute]

On Sunday, March 6, 2022 at 3:58:17 PM UTC, AMuzi wrote:
>
> Crashed frames with damaged forks and changed head angles
> exhibit wild changes, as do specialty machines designed for
> over- or under- steer effect.
>

No, that is only half right. A slightly oversteering bike may be desirable for the fast reflexes and close quarters of a domestique in professional bike racing, but a point will soon arrive where oversteer is counterproductive, strictly for posers who want to pretend they're faster than the laws of physics. An understeering bike, by contrast, is designed for stability and any declared "understeering" bike which "exhibit[s] wild changes" is either not understeering at all but neutral, or has been so incompetently designed -- or implemented -- with such a huge excess of understeer that the steering would be very heavy and the bike in general would be tiresome to ride. The idea is really to move the bike away from true neutral steering, which is unpredictable and unmanageable, by the smallest amount which will suffice, and beyond that in small steps to an accommodation with environments both natural like my hills and small roads and manmade like professional bike racing, without compromising manageability too much.

One day, when the wretched Vehicular Cycling movement is only a memory, and those who think they have a right to a road clear of slower cyclists in order to proceed to the office at 25mph have gasped their last, all bikes will at last be like mine if not in appearance, at least close in amount of understeer. This is already the case on the majority of bikes sold in the bicycling nations.

Andre Jute
Moderation is the watchword. My experimental sidekick, Franki-boy, will shortly be along with an algorithm.

[Andre Jute]

"It's not a bug! It's a feature!" -- Bill Gates
"It's not a crash, it's a field enhancement of Bianchi's design!" -- Andrew Muzi
'Heh-heh!" -- Andre Jute

[AMuzi]

On 3/6/2022 11:53 AM, Frank Krygowski wrote:
> On 3/6/2022 10:58 AM, AMuzi wrote:
>> On 3/5/2022 8:45 PM, Frank Krygowski wrote:
>>> On 3/5/2022 2:25 PM, AMuzi wrote:
>>>> On 3/5/2022 12:25 PM, Frank Krygowski wrote:
>>>>> On 3/5/2022 11:02 AM, AMuzi wrote:
>>>>>> On 3/5/2022 9:11 AM, Dieter Britz wrote:
>>>>>>> On Sat, 05 Mar 2022 02:50:18 -0800, Andre Jute wrote:
>>>>>>> [...]
>>>>>>>> My own bikes are all set up to understeer. The
>>>>>>>> consequential
>>>>>>>> predictability and stability of line almost regardless
>>>>>>>> of road surface

>>>>>>>> makes the essential difference on downhill

>>> point would describe a circle. The circle would be

That's all well considered and well written.

Generally if one can readily observe rise or fall through 90
degrees,(45 each side) something is wrong/ damaged.

Outliers such as classic roadsters are obvious in their rise
without measuring tools. The effect on handling is apparent
and dramatic immediately to riders inexperienced with the
design.

[sms]

On 3/4/2022 7:53 AM, AMuzi wrote:

> On 3/4/2022 8:49 AM, Dieter Britz wrote:
>> I hear and read mention of a "responsive frame". What does
>> this mean, and what kind of frame is responsive, and not?
>>
>

> It's a marketing term, unrelated to quantifiable values.

I think that generally "responsive" is thought to mean stiff, short
chain stays, and a steep head angle. As opposed to a touring frame that
is less stiff, has longer chain stays, and a more slack head tube angle.

The steering responsiveness, based on the stem length, is another
factor. I recall my first folding bicycle, the orginal Dahon
<https://upload.wikimedia.org/wikipedia/commons/1/1d/Dahon_Classic_III_drive_side_bicycle_bootiebike_com_1000.jpg>
with almost no stem length. Took a bit of getting used to how responsive
the steering was. That folding frame member actually made the frame
pretty stiff, stiffer than most modern folders with the very long steer
tube.

[Jeff Liebermann]

On Fri, 4 Mar 2022 14:49:23 -0000 (UTC), Dieter Britz
<dieterh...@gmail.com> wrote:

>I hear and read mention of a "responsive frame". What does
>this mean, and what kind of frame is responsive, and not?

As I understand it, "responsive" requires that something responds to
an intentional action by the rider, usually the steering. For
example, the steering would be considered responsive if the front
wheel turns accurately in response to turning the handlebars. The
same arrangement would be considered unresponsive if the various
mechanical parts involved acted as if they were made from rubber or
had dead zones.

The term "responsive" is often used in reference to the effects of
adjustable length forks, which I suspect inspired the "frame" part of
the question.

"Bike Suspension Basics"
<https://www.rei.com/learn/expert-advice/suspension.html>
"A short-travel bike is more responsive to steering input, which can
translate to twitchiness going downhill. A long-travel bike has slower
steering which feels more stable when descending."

More of the same:
<https://www.google.com/search?q=bicycle+suspension+responsiveness>



--
Jeff Liebermann je...@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

[Frank Krygowski]

Well, I don't have a roadster to measure, but I still don't see how a
rise is possible.

I couldn't find details on roadster geometry, so I scaled this image:
https://georgehahn.com/the-raleigh-dl-1-my-dream-bike/
I get a head tube angle of about 66 degrees and a trail about 107mm.

Putting it through my equations above, that yields a negligible drop of
0.6mm at at steering angle of ten degrees, and a large drop of 11.6mm at
a steering angle of 45 degrees. The equations and geometry don't predict
a rise.

If I've made a mistake, I'm curious what it is.

BTW, I tried for a bit to measure the drops using a dial indicator
clamped to my saw table. It's devilishly hard. Too many degrees of
freedom, and it requires constantly fiddling with the bike to seek the
top of the top tube. Pinching a vertical meter stick to the side of the
top tube seems the most reliable way to get at least a sense of the
vertical motion.

--
- Frank Krygowski

[Tom Kunich]

I'm wondering why Frank would attempt to measure over or under or neutral steering through a 360 degree circle. Why LOGIC would dictate that neutral steering should be the same through 360 degrees simple observation would show you that the rear 180 degrees of the circle must contend with rake and trail. That would cause a rise of the top tube in the back side of the circle. Even the front 180 degrees is somewhat effected by this, you never use more than the front 90 degrees if you are going over 10 mph.

[Frank Krygowski]

The full rotation of the handlebars in my analysis was used only to
define the geometry - that is, the circular path of the tire-to-road
contact patch. Obviously, only a portion of that circular path is used
while riding the bike. That's why I did no computations for steering
angles greater than 45 degrees.

The fact that the tire contact patch travels in a slanted circle means
the bike frame must begin to drop any time the steering is moved away
from center.

If you see a mistake in my geometry, please point it out, preferably
using mathematics.

Again, my analysis is for a tire of zero width. If you want to take the
analysis further, that might be an item to address. I suspect the
effect, if any, is negligible for common tire sizes.

--
- Frank Krygowski

[Andre Jute]

On Monday, March 7, 2022 at 4:38:03 PM UTC, Frank Krygowski wrote:
>
>If you see a mistake in my geometry, please point it out, preferably
using mathematics.
>

Frank-boy, you have a bloody cheek trying to set the rules of converse when you beg us for help with something that is beyond your brainpower and education.

>
> Again, my analysis is for a tire of zero width. If you want to take the
> analysis further, that might be an item to address. I suspect the
> effect, if any, is negligible for common tire sizes.
>

Sure thing, Franki-boy, we all saw you try to pass off a round knife-edge as a wheel. We were just wondering whether you're monumentally slack or without the slightest shred of imagination. See, a bicycle tyre is rounded, which makes for a domed shape when you take a section of the tyre at the contact patch centre, and so the distance from the contact patch to the hub centre varies as the bike leans over in a corner, with a number of consequential effects. It is possible in these circumstances to arrange the dynamic effect of the static geometry so that Andrew Muzi's holy grail of zero rise or fall is achieved at the headset and it seems to me that it is commonly approached, it being another matter whether bike designers even know about it when they slap together some tried and true angles.These effects can possibly be further fine-tuned to zero rise and fall by the obverse of the linkage geometry used in automobiles to keep the wheel upright* but I think that is way beyond your demonstrated capabilities, or rather demonstrated lack of capability.** The math, and piccies for wannabe hotrodders like you, is in my book DESIGNING AND BUILDING SPECIAL CARS. Go look it up, sport.
>
Andre Jute
* In fact, a close approximation of a bicycle which didn't change the wheelbase length with each movement up and down, was possible with a bicycle fork designed by a French auto racer for MTB bikes. It's possible this dual wishbone bicycle fork was called "Cobra" -- one of my googlebugs will be here shortly with the designer's and the fork's names. About twenty years ago I searched for an NOS fork of this design but the only one for sale was ten grand, a bit rich for even my blood. More recently, the same design appeared on the front suspension of the Honda Goldwing.
** For those with greater analytical brainpower than Franki-boy, I suspect that zero rise or fall when the handlebars are turned is a symptom of a genuinely neutral-handling bike, which as I explained before can break unpredictably between over- and under-steer and is therefore undesirable for any but the top rank of professional bike racers. If you want to see neutral handling two-wheelers, watch MotoGP, in which the riders control the characteristics of roadholding and handling by shifting their own bodyweight around in an extreme manner requiring a great deal of skill, knowledge and bravery. Weight transfer is another name for rise or fall and, to state the obvious, the designer and the cyclist both want it under their own control rather than accept the pitiless physics of hardwiring an error into the frame and the fork.

[Tom Kunich]

Frank is particularly stupid inasmuch as Andrew explained a simple test and I repeated it of no rise or fall of the top tube at the head tube when the handlebars are turned limit to limit. We both used a 4' bubble level and they are, I'm afraid, of vastly superior accuracy than Frank's approximations of his own false reality. That he could think that neutral steering means 360 degrees means that he hasn't a grasp of rake and trail. This means that neutral geometry could only be maintained through 180 degrees.

One of the projects I completed had 12 directions of motion. I designed the unit to use stepping motors which meant that for accuracy they had to have no gear play beyond tight limits. Now why would I have had to have to explain to supposed trained mechanical engineers what gear play means? Why for the same reason that I ended up being project engineer on so many projects - because it is not a degree that makes an engineer but a quest for knowledge. The ability to think a problem out to its end. These sorts of mechanical engineers go into aerospace firms that will pay them vast sums of money that Frank believes should be given freely to him. Those who I was unfortunate to have working with or for me, either were simply beginning to catch on or like Frank would never make the grade.

[Andre Jute]

I saw you guys trying to help Franki-boy and thought I'd better do my bit to show willing. But it is probably wasted time. Krygowski just isn't capable of the subtleties that remain to be explained in bicycle geometry.
>
As an aside, I continue to be amazed by the fact that automobile suspension geometry is so much better understood than bicycle geometry. There's hope of a better future of course, for instance from those scholars in Cologne pushing bikes to each across a hall on a campus in Cologne, and speculating and making prototypes to test bicycle stability, and other academic efforts from people who don't need to earn a commercial income.
>
Andre Jute
I salute a cycling tomorrow.
>
PS. I have a bike application of stepper motors, or possibly just one reversible stepper motor, sitting on the axle of a Shimano Nexus hub and actually changing the gears on my Trek Smover, which is a full service full auto Di2 bike. It's an amazingly small thing, totally enclosed in plastic only a couple of inches to a side and about three-quarters of an inch thick.
>

[Tom Kunich]

I'm of the opinion that rear axle 8 speeds with electical shifting would be good commuters but couldn't be constructed to have the gear range and strength of the normal manual derailleur. While electronic shifting such as Di2 works better than manual for less messing about, manual is certainly good enough and requires less messing with.

[Lou Holtman]

On Wednesday, March 9, 2022 at 5:06:00 PM UTC+1, Tom Kunich .

>
> One of the projects I completed had 12 directions of motion.

12 direction of motion? I don't understand. I know translation in X,Y and Z and rotation Rx, Ry and Rz. I can position and orientate an object in a 3 D space using these 6 degrees of freedom. What did I miss?

lou

[Frank Krygowski]

On 3/9/2022 11:05 AM, Tom Kunich wrote:
>
> Frank is particularly stupid inasmuch as Andrew explained a simple test and I repeated it of no rise or fall of the top tube at the head tube when the handlebars are turned limit to limit. We both used a 4' bubble level and they are, I'm afraid, of vastly superior accuracy than Frank's approximations of his own false reality. That he could think that neutral steering means 360 degrees means that he hasn't a grasp of rake and trail. This means that neutral geometry could only be maintained through 180 degrees.

Well, that was completely devoid of facts!

I computed drops of less than a millimeter at a ten degree steering
angle - specifically, 0.6mm for the Raleigh Roadster. It was less for
other frame geometries, but it was always a drop. The trigonometry
wasn't terribly difficult.

As _you_, Tom, can easily show by trigonometry (right?) a 0.6 mm drop at
the end of a four foot level causes the angle of the level to change by
0.03 degrees.

Do you think you can detect an angle of 3/100 degree by reading a level?

My main point was a conventional bike does not _rise_ when the steering
is turned. At least for the case of a vertical bike and negligible tire
width, it must fall. It falls microscopically for small steering angles
and more as the steering angle increases, but it does not rise. And my
simple measurements (more sensitive than yours, BTW) confirm that.

If there's something I'm missing in the geometry or trigonometry, spell
it out. And skip the insults.

--
- Frank Krygowski

[Jeff Liebermann]

12 degrees of freedom would be a Stewart platform, which is used in
flight simulators:
<https://en.wikipedia.org/wiki/Stewart_platform>
It's really only 6 degrees of freedom but Grübler's forumula declares
it to be 12. The additional 6 degrees are the rotation of the legs,
which have no effect on the motion of the platform.

"Everything About the Degrees of Freedom of a Robot"
<https://www.mecharithm.com/degrees-of-freedom-of-a-robot/>
(near the bottom of web page).

Drivel: Degrees of Motion is band:
<https://www.discogs.com/artist/7294-Degrees-Of-Motion>

[Jeff Liebermann]

On Wed, 09 Mar 2022 10:38:05 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

I forgot to mumble about the 7th degree of freedom, which is to mount
a 6 axis robot on rails or suspend from a gantry:
<https://www.linearmotiontips.com/what-is-a-7th-axis-also-known-as-an-rtu-and-when-is-it-used/>

Also, the 3 rotational axis are commonly called yaw, pitch, and roll.

[Lou Holtman]

On Wednesday, March 9, 2022 at 7:38:14 PM UTC+1, jeff.li...@gmail.com wrote:
> On Wed, 9 Mar 2022 09:34:26 -0800 (PST), Lou Holtman
> <lou.h...@gmail.com> wrote:
>
> >On Wednesday, March 9, 2022 at 5:06:00 PM UTC+1, Tom Kunich .
> >>
> >> One of the projects I completed had 12 directions of motion.
>
> >12 direction of motion? I don't understand. I know translation in X,Y and Z and rotation Rx, Ry and Rz. I can position and orientate an object in a 3 D space using these 6 degrees of freedom. What did I miss?
> >lou
> 12 degrees of freedom would be a Stewart platform, which is used in
> flight simulators:
> <https://en.wikipedia.org/wiki/Stewart_platform>
> It's really only 6 degrees of freedom but Grübler's forumula declares
> it to be 12. The additional 6 degrees are the rotation of the legs,
> which have no effect on the motion of the platform.

Pff… That is a weird definition.

Lou

[Lou Holtman]

On Wednesday, March 9, 2022 at 7:43:18 PM UTC+1, jeff.li...@gmail.com wrote:

>
> Also, the 3 rotational axis are commonly called yaw, pitch, and roll.

Not in my line of work.


Lou

[AMuzi]

I cannot compose the formulae so I'll trust you on that.

How did you allow for the net rake diminishing as the wheel
turns while simultaneously changing the head angle? Too
complex for me.

[AMuzi]

On 3/9/2022 1:01 PM, Lou Holtman wrote:
> On Wednesday, March 9, 2022 at 7:38:14 PM UTC+1, jeff.li...@gmail.com wrote:
>> On Wed, 9 Mar 2022 09:34:26 -0800 (PST), Lou Holtman
>> <lou.h...@gmail.com> wrote:
>>
>>> On Wednesday, March 9, 2022 at 5:06:00 PM UTC+1, Tom Kunich .
>>>>
>>>> One of the projects I completed had 12 directions of motion.
>>
>>> 12 direction of motion? I don't understand. I know translation in X,Y and Z and rotation Rx, Ry and Rz. I can position and orientate an object in a 3 D space using these 6 degrees of freedom. What did I miss?
>>> lou
>> 12 degrees of freedom would be a Stewart platform, which is used in
>> flight simulators:
>> <https://en.wikipedia.org/wiki/Stewart_platform>

>> It's really only 6 degrees of freedom but Grübler's forumula declares

>> it to be 12. The additional 6 degrees are the rotation of the legs,
>> which have no effect on the motion of the platform.
>

> Pff… That is a weird definition.
>
> Lou
>
+1

For subtractive machining the tools are now called "5-axis".
I learned X, Y Z axis in machining. I think it's the sales
department more than logicians who describe the ability to
cut double compound curves such as a nuclear submarine
'silent' propeller as "5-axis" machining.

(I'm told this will all be 3D printed at some date hence.)

[Lou Holtman]

We have a couple 5 axis machining tools in our workshop at work; translation in x, y and z direction and rotation around two axis. It is a joy to watch them at work and I can design more complex parts ;-) that can be made in house within a couple of days. 3D printing and rapid prototyping is also amazing. Complex plastic parts available overnight right from my 3D CAD application. I work 41 years now at the company and the progress is amazing during that period. I will be kicked out next year. Hmmm….

Lou

[Tom Kunich]

X, Y, Z and rotation. Y motion occurs in two different areas moving sample plates back and forth into different areas. Another plane of motion is heating another cooling Picking up platelet sample nozzles and ejecting them etc. etc. etc. Frank seems to think only in 3 dimensions and not actual activities of motor drives. Picking up primer in on platelet, moving it over and depositing an exact amount into the actual samples, moving the table to move the platelet from one table onto another that places the samples in a thermocycler, moving the main table over to the nozzle container and ejecting only the number of nozzles that have been used. The first company I did this for it was all written in assembly language and at another company I did a far more complex firmware in C and it took up less memory and used a far faster microprocessor. These were all considered planes of motion because they all had to occur with perfect timing and perfect volume exchanges. You can trust the blood you get from a blood bank because of my work. The first example of the Pro/Pette https://www.ebay.com/itm/163276237068?hash=item260405a90c:g:yBYAAOxy7AxSK3wI was the one that two PhD's said could not be accomplished with less than TWO IBM supercomputers. The Pro/pette was a bit smaller than that.

[Frank Krygowski]

It wasn't necessary for the analysis. All I had to do was determine the
path of the tire-to-ground contact point.

BTW, I later found in _Bicycle Technology_ by Van der Plas & Baird,
~p.138, the authors give a name to the radius of the circle I described.
Interestingly, they say it's the "effective trail" or "Stability Index."

They claim this is the quantity that I referred to weeks ago when I
mentioned its graph in DeLong's _Guide to Bicycles and Bicycling_. (I
haven't confirmed that.) Their book reprints DeLong's graph, and his
graph of "handling qualities" vs. trail.


--
- Frank Krygowski

[Frank Krygowski]

I agree, this stuff is great fun to watch, especially (for me) the
machining.

I first saw 3d printing at a place I worked in 1990. Photosensitive
plastic resin was hit with a laser beam, with each layer then lowered a
few thousandths of an inch and the process repeated. The part took many
hours, then needed to be "baked" in a UV oven to fully harden. It was
expensive and slow, but it allowed faster prototypes of complex
electrical connectors.

Now both CNC and 3D printing are done by home hobbyists. (I'm still
feeding my lathe cutting tool by hand most of the time.)


--
- Frank Krygowski

[Jeff Liebermann]

Not a problem. In robotics and machining, the rotational axes are a,
b, and c. In maritime, aircraft and satellite, they're roll, pitch,
and yaw.
<https://en.wikipedia.org/wiki/Ship_motions>
<https://en.wikipedia.org/wiki/Aircraft_principal_axes>
There are also those who favor the Greek letters, alpha, beta, and
gamma:
<https://i.stack.imgur.com/2b9B5.png>
<http://lavalle.pl/vr/node77.html>

[Lou Holtman]

‘We’ define a X, Y and Z axis and then translation and rotation is also defined. Everyone knows what you mean.

Lou

[Andre Jute]

And in the theatre, as of today when I made it up, roll, pitch and yaw will be incredulity, death spiral and fan. But we'll continue with the well-established stage right and stage left.-- AJ

[Jeff Liebermann]

On Wed, 9 Mar 2022 22:37:00 -0800 (PST), Lou Holtman

<lou.h...@gmail.com> wrote:

>On Thursday, March 10, 2022 at 1:39:47 AM UTC+1, jeff.li...@gmail.com wrote:
>> On Wed, 9 Mar 2022 11:03:40 -0800 (PST), Lou Holtman
>> <lou.h...@gmail.com> wrote:
>>
>> >On Wednesday, March 9, 2022 at 7:43:18 PM UTC+1, jeff.li...@gmail.com wrote:
>> >> Also, the 3 rotational axis are commonly called yaw, pitch, and roll.
>>
>> >Not in my line of work.
>> >Lou
>> Not a problem. In robotics and machining, the rotational axes are a,
>> b, and c. In maritime, aircraft and satellite, they're roll, pitch,
>> and yaw.
>> <https://en.wikipedia.org/wiki/Ship_motions>
>> <https://en.wikipedia.org/wiki/Aircraft_principal_axes>
>> There are also those who favor the Greek letters, alpha, beta, and
>> gamma:
>> <https://i.stack.imgur.com/2b9B5.png>
>> <http://lavalle.pl/vr/node77.html>

>‘We’ define a X, Y and Z axis and then translation and rotation is also defined. Everyone knows what you mean.
>Lou

We beg to differ, somewhat. X, Y, and Z locate a position or linear
movement in space. Roll, pitch, and yaw define a rotational movement
in space. You cannot have movement without first locating the object
that moves. Therefore, as you indicate, X, Y, and Z must be specified
before A, B, and C. As I vaguely recall, G code use A, B, and C.

Whether one uses roll pitch yaw, A B C, or Alpha Beta Gamma are
religious issues similar to the direction of current flow, where those
in electronics use Ben Franklin's convention of "hole" flow (plus ->
minus), while most other disciplines use electron flow (minus ->
plus).

Some of my background is marine radio, where vessel roll, pitch, and
yaw are the common terms.

[Tom Kunich]

On Thursday, March 10, 2022 at 1:22:39 AM UTC-8, Andre Jute wrote:
> On Thursday, March 10, 2022 at 12:39:47 AM UTC, jeff.li...@gmail.com wrote:
> > On Wed, 9 Mar 2022 11:03:40 -0800 (PST), Lou Holtman
> > <lou.h...@gmail.com> wrote:
> >
> > >On Wednesday, March 9, 2022 at 7:43:18 PM UTC+1, jeff.li...@gmail.com wrote:
> > >> Also, the 3 rotational axis are commonly called yaw, pitch, and roll.
> >
> > >Not in my line of work.
> > >Lou
> > Not a problem. In robotics and machining, the rotational axes are a,
> > b, and c. In maritime, aircraft and satellite, they're roll, pitch,
> > and yaw.
> > <https://en.wikipedia.org/wiki/Ship_motions>
> > <https://en.wikipedia.org/wiki/Aircraft_principal_axes>
> > There are also those who favor the Greek letters, alpha, beta, and
> > gamma:
> > <https://i.stack.imgur.com/2b9B5.png>
> > <http://lavalle.pl/vr/node77.html>
> >

> And in the theatre, as of today when I made it up, roll, pitch and yaw will be incredulity, death spiral and fan. But we'll continue with the well-established stage right and stage left.-- AJ

The people here who have done nothing with their lives are comedic is response to people who have.

Now that Pfizer has been forced to release papers concerning their vaccine. Of less that 50,000 investigated cases there were about 160,000 physical abnormal responses to it. Now some of these were no doubt abnormal injection site pain. But there were 100,000 concerning musculature and neurological responses that could be permanent disabilities both physical and mental and 1,223 people died of this specific vaccine in only 48,000 investigations! This is FAR above (greater than or equal to 2%) the acceptable limits for vaccines.

What this tells me is that those who know medicine PRACTICE medicine and those who don't go into civil service to garner large salaries despite their incompetence. This information was supposed to be public information and it took a group of THOUSANDS of doctors to sue under the Freedom of Information Act to get it release before 2097! What we are seeing is that Frank's favorite belief that we should have socialized medicine means that we should have socialized incompetent medicine. This suggests to me that Frank has a personal reason to want to void the 2nd Amendment.

This has become not a debate about a questionable illness that appears to have been developed under US taxpayer money, but a level of attempting to hide how badly mRNA vaccines actually are. They are stiff today trying to force your children to take a fake vaccine that could be responsible for the death of your children. And who is pressing these sorts of things? The PRESIDENT! This is clear and present grounds for impeachment.

[Tom Kunich]

I don't know how you can understand what he means when HE doesn't know what he means. For every motion requiring a different motor, that is an additional axis of motion. Rather than accept that he wants to foolishly talk about X,Y and Z axis as if that had any bearing. He is a stupid person who makes stupid statements. He has never worked in the industry and wants to only argue endlessly which does nothing more than show his own college trained ignorance.

[Frank Krygowski]

On 3/10/2022 12:27 PM, Tom Kunich wrote:
>
> What this tells me is that those who know medicine PRACTICE medicine and those who don't go into civil service to garner large salaries despite their incompetence. This information was supposed to be public information and it took a group of THOUSANDS of doctors to sue under the Freedom of Information Act to get it release before 2097! What we are seeing is that Frank's favorite belief that we should have socialized medicine means that we should have socialized incompetent medicine. ...

Typical Kunich nonsense!

We just returned from a visit to our Primary Care Physician, who's
actually a friend of mine. Later this week we'll have a visit from an
out-of-state physician relative who trained and worked with this
physician. Both these men have decades of experience PRACTICING medicine
- in contrast to a certain unemployed Californian who seldom kept a job
for over two years.

Today's visit was "Masks required." Both of these physicians are quite
certain that COVID is real and serious. And both have ranted about the
inefficiencies and failings of America's health care system compared to
those of other countries. All of that is in contrast to that certain
Californian's theories and rants.

BTW, one of their main complaints about the U.S. system is the
near-absolute power given to flunkies working for insurance companies.
Our PCP has been repeatedly outraged that tests or medications he
competently prescribes get challenged or denied, in an effort to reduce
insurance company expenses.

Granted, those roadblocks happened only a few times for my wife and me.
Luckily, the insurance package provided to retired professors really is
excellent. There are benefits to being competent in a good job for
longer than two years.


--
- Frank Krygowski

[Jeff Liebermann]

On Thu, 10 Mar 2022 09:33:20 -0800 (PST), Tom Kunich
<cycl...@gmail.com> wrote:

>On Wednesday, March 9, 2022 at 10:37:03 PM UTC-8, Lou Holtman wrote:
>> On Thursday, March 10, 2022 at 1:39:47 AM UTC+1, jeff.li...@gmail.com wrote:
>> > On Wed, 9 Mar 2022 11:03:40 -0800 (PST), Lou Holtman
>> > <lou.h...@gmail.com> wrote:
>> >
>> > >On Wednesday, March 9, 2022 at 7:43:18 PM UTC+1, jeff.li...@gmail.com wrote:
>> > >> Also, the 3 rotational axis are commonly called yaw, pitch, and roll.
>> >
>> > >Not in my line of work.
>> > >Lou
>> > Not a problem. In robotics and machining, the rotational axes are a,
>> > b, and c. In maritime, aircraft and satellite, they're roll, pitch,
>> > and yaw.
>> > <https://en.wikipedia.org/wiki/Ship_motions>
>> > <https://en.wikipedia.org/wiki/Aircraft_principal_axes>
>> > There are also those who favor the Greek letters, alpha, beta, and
>> > gamma:
>> > <https://i.stack.imgur.com/2b9B5.png>
>> > <http://lavalle.pl/vr/node77.html>

>> ‘We’ define a X, Y and Z axis and then translation and rotation is also defined. Everyone knows what you mean.

>I don't know how you can understand what he means when HE doesn't know what he means. For every motion requiring a different motor, that is an additional axis of motion. Rather than accept that he wants to foolishly talk about X,Y and Z axis as if that had any bearing. He is a stupid person who makes stupid statements. He has never worked in the industry and wants to only argue endlessly which does nothing more than show his own college trained ignorance.

Lou Holman's question to YOU was:

> On Wednesday, March 9, 2022 at 5:06:00 PM UTC+1, Tom Kunich .
>> One of the projects I completed had 12 directions of motion.

> 12 direction of motion? I don't understand. I know translation
> in X,Y and Z and rotation Rx, Ry and Rz. I can position and
> orientate an object in a 3 D space using these 6 degrees of
> freedom. What did I miss?
>
> lou

I provided my answer, which you seem to regard as "foolishly talk
about X, Y and Z axis". No problem. You're entitled to your opinion.

So, could you please answer his question about how you implemented 12
degrees of freedom into a blood sample handling device? After all,
the question was addressed to you, not me. Did your project have 12
motors? If so, how were they arranged and how did you program their
motion which presumably involving Euler Angles, which are the basis of
robotic motion control:
<https://robodk.com/blog/robot-euler-angles/>
<https://en.wikipedia.org/wiki/Euler_angles>
More:
<https://www.google.com/search?q=euler+angles+robotics>

If it makes you feel any better, I had great difficulty learning how
the coordinate systems and coordinate translation/rotation worked in
CNC machining. I can't claim to be even minimally functional at CNC
or robotics programming. At best, I understand the basic principles
and some of the fundamentals. However, since the project you
completed used all 12 directions of motion (commonly known as degrees
of freedom), you should be able to properly explain how it works.

Marginally related drivel on a 3 axis CNC mill conversion:
<http://www.learnbydestroying.com/jeffl/pics/CNC-conversion/index.html>
<http://www.learnbydestroying.com/jeffl/CNC%20Conversion%20Project/CNC.html>
The vertical mill is a Shizuoka ST-N. KRS servos and drivers. Newker
990(?) controller. It would have been 4 axis, except the owner sold
the rotary indexer. Three of us worked on it over a period of 1.5
years, including a spindle rebuild. The most difficult part was
decoding the manual, which was a rather bad English translation of the
original Chinese. It's been cutting metal (and making a profit) for
the past 5 years.

[AMuzi]

Chinese? Shizuoka is (was?) a Japanese precision tool maker
in Tokyo.

[John B.]

I really find all this discussion about Covid rather silly. The actual
Statistics show that in Thailand, where I read, in yesterday's news,
that 97% of all Thais wear masks the incident of Covid deaths is 335/1
million population while in the U.S., where I read (right here) that
masks are unnecessary the Covid death rate is some 2963/1m. That is
about 9 times more in the non-mask country.
--
Cheers,

John B.

[Jeff Liebermann]

Shizuoka ST-N. SHIZUOKA MACHINE TOOL CO., LTD. Made in Shizuoka,
Japan during late 1970's or early 1980's vintage. The company is very
much alive, but does not want to support their older products:
<http://www.shizuokatekko.co.jp>
(Use Chrome browser and the Google Translate extension to translate
the web pages into English). Very good quality mill. However, the
overall quality was ruined by the original Bandit controller, which
was difficult to program, and would blow up electronics randomly.
Fortunately, we found the one person on the planet who still supports
the Bandit controller. With his help, the Bandit was kept alive until
we decided that it was time for a servo, driver, and controller
transplant. In the end, we replaced almost everything except the
basic Shizuoka mill, the Bandit i/o system, and the power and
switching electronics.

I found some old (2016) pre-CNC photos that I made in case we had to
resurrect something:
<http://www.learnbydestroying.com/jeffl/Shizuoka-Mill/>

As I recall, the total cost of the CNC conversion, including
rebuilding the spindle, was about $2000. Of course, there was
considerable barter and the labor of those involved was essentially
free.

[AMuzi]

Thanks! That's a nice looking machine and your photo skills
are excellent.

[Frank Krygowski]

We could have used you about ten years before I retired. Besides some
small sized educational mills, our NC lab used an ancient Bridgeport NC
mill, running programs on paper tape. Our electronic tech guys had more
and more trouble keeping the electronics working (sorry, I don't know
what the specific problems were), and Bridgeport was no help. I remember
being told "The only guy left at Bridgeport who still understood that
just retired."

It worked out OK, though. The difficulties ultimately let us convince
the administration we needed a brand new Haas mill, plus software to aid
in programming it.


--
- Frank Krygowski

[AMuzi]

South Bend keeps serial number records from 1906 so spares
and maintenance for our 1939 lathe were no problem at all.

[Jeff Liebermann]

On Thu, 10 Mar 2022 21:35:00 -0500, Frank Krygowski
<frkr...@sbcglobal.net> wrote:

>We could have used you about ten years before I retired. Besides some
>small sized educational mills, our NC lab used an ancient Bridgeport NC
>mill, running programs on paper tape.

The owners original shop, started in about 1977, was also running on
paper tape using a Model 33ASR Teletype. I made it fairly clear that
once everything had been "modernized" to RS-232, I wanted the 33ASR
machine. Instead, someone sent it to the metal scrap dealer. Grrrr.

The current shop has a Bridgeport vertical mill (background right):
<http://www.learnbydestroying.com/jeffl/pics/CNC-conversion/CNC-conversion-01-001.jpg>

Before it can be used for CNC, the table and saddle feed screws need
to be replaced with precision ball screws and bearings. Note the
prices:
<https://www.icai-online.com/ballscrews/>
However, if I were buying a kit, it would be from Rockford Ball Screw:
<https://rockfordballscrew.com/ballscrews/bridgeport-kits/>

>Our electronic tech guys had more
>and more trouble keeping the electronics working (sorry, I don't know
>what the specific problems were), and Bridgeport was no help. I remember
>being told "The only guy left at Bridgeport who still understood that
>just retired."

That might be the case 10 years ago, but today, there are still
thousands of Bridgeport mills (and clones) still in service. Finding
mechanics who know the machinery is becoming difficult, but not
impossible. Or, you could just buy the cookbook and Learn by
Destroying(tm):
<https://www.amazon.com/s?i=stripbooks&rh=p_27%3AILION+Industrial+Services+LLC>

>It worked out OK, though. The difficulties ultimately let us convince
>the administration we needed a brand new Haas mill, plus software to aid
>in programming it.

If the school has the money, that's usually the best way. It's
difficult for students to learn on a machine that doesn't work.
However, when I went to skool (1960's), the situation was different.
The only machines we could get were donated. You can easily guess
which machines the schools received. I think I spent more time doing
maintenance on those machines that cutting metal. However, times have
changed. Most schools became tired of fixing donated hardware.
Therefore, donated machines now require the inclusion of a service
contract. I'm undecided which was better... having a working machine
to learn on, or learning how the machine works by first fixing it.

[Jeff Liebermann]

On Thu, 10 Mar 2022 21:09:10 -0600, AMuzi <a...@yellowjersey.org> wrote:
>South Bend keeps serial number records from 1906 so spares
>and maintenance for our 1939 lathe were no problem at all.

My father's lingerie factory had an old South Bend lathe. One of my
auto repair shop customers and the college Rose Float construction lab
also had one. I don't recall the age or model numbers. I became
rather adept at lacing (splicing) flat leather drive belts with
Clipper Hooks:
<https://www.flexco.com/EN/Product-Systems/Mechanical-Belt-Fastening-Systems/Clipper-Wire-Hook-Fastening-System.htm>

3rd party SBL docs:
<https://www.amazon.com/Basic-Maintenance-Vintage-South-Lathe/dp/1671537610>
<https://www.amazon.com/Guide-Renovating-South-Lathe-Model/dp/1482364883>

[John B.]

On Thu, 10 Mar 2022 21:46:19 -0800, Jeff Liebermann <je...@cruzio.com>
wrote:

Why fiddle with the paper tape? Just run the machine.

The school I went to had both a fully equipped wood working shop and a
machine shop and actually made stuff for sale. The wood shop made the
forms, then had a local foundry make the castings and the machine shop
finished the machines. We made wood planers, bench grinders and I saw
the castings for a band saw although I don't remember that we ever
finished one.

I have no idea of the finances but certainly sales of machinery must
have helped to finance things.

I don't remember much about the wood working guy other then he had
been there since my father was in school but the Machine shop guy used
to talk about "going in the shop" when he was 12 years old. No
advances schooling, teacher's collage, or... Just 50 years of
experience (:-)
--
Cheers,

John B.

[ritzann...@gmail.com]

On Friday, March 11, 2022 at 12:17:09 AM UTC-6, jeff.li...@gmail.com wrote:
> On Thu, 10 Mar 2022 21:09:10 -0600, AMuzi <a...@yellowjersey.org> wrote:
> >South Bend keeps serial number records from 1906 so spares
> >and maintenance for our 1939 lathe were no problem at all.
> My father's lingerie factory had an old South Bend lathe.

Why would a lingerie factory have a metal working lathe? To make parts for the sewing machines?

[AMuzi]

On 3/11/2022 12:17 AM, Jeff Liebermann wrote:
> On Thu, 10 Mar 2022 21:09:10 -0600, AMuzi <a...@yellowjersey.org> wrote:
>> South Bend keeps serial number records from 1906 so spares
>> and maintenance for our 1939 lathe were no problem at all.
>
> My father's lingerie factory had an old South Bend lathe. One of my
> auto repair shop customers and the college Rose Float construction lab
> also had one. I don't recall the age or model numbers. I became
> rather adept at lacing (splicing) flat leather drive belts with
> Clipper Hooks:
> <https://www.flexco.com/EN/Product-Systems/Mechanical-Belt-Fastening-Systems/Clipper-Wire-Hook-Fastening-System.htm>
>
> 3rd party SBL docs:
> <https://www.amazon.com/Basic-Maintenance-Vintage-South-Lathe/dp/1671537610>
> <https://www.amazon.com/Guide-Renovating-South-Lathe-Model/dp/1482364883>
>

Yes, I was taught my an old machinist; it isn't all that
difficult.

[Jeff Liebermann]

On Fri, 11 Mar 2022 00:27:13 -0800 (PST), "russell...@yahoo.com"
<ritzann...@gmail.com> wrote:

>On Friday, March 11, 2022 at 12:17:09 AM UTC-6, jeff.li...@gmail.com wrote:
>> On Thu, 10 Mar 2022 21:09:10 -0600, AMuzi <a...@yellowjersey.org> wrote:
>> >South Bend keeps serial number records from 1906 so spares
>> >and maintenance for our 1939 lathe were no problem at all.
>> My father's lingerie factory had an old South Bend lathe.

>Why would a lingerie factory have a metal working lathe? To make parts for the sewing machines?

Yes, but not always parts. This is from before multi-purpose sewing
machines and computah driven automation became the standard. If a
garment needed to be sewn in some exotic manner, a purpose built
"attachment" was designed and built to do the job. The attachments
often needed to be driven by the sewing machine, usually in the form
of a drive shaft, gears and cams, which was where the lathe was
useful.

At the time (1950's and 60's), domestic US industrial sewing machines
were too expensive. Japan was recovering from WWII and shipping
marginal products made from available scrap. That left Europe, which
had rapidly recovered and were shipping precision machines at
tolerable prices (Pfaff, Rimoldi, Bernina, etc). Standardized parts
and overnight shipping were years in the future. So, we made many of
our own repair parts, usually with a hand file and drill press, but
sometimes using the lathe.

Incidentally, moving fragile nylon net through mechanical mechanisms
without drag, bunching or tearing is a real art requiring everything
to be polished and smooth. Today, such mechanisms would be made on a
mill. 60 years ago, they were made from soldered nickel-silver sheet
metal. Today, it's commonly used for making jewelry:
<https://www.google.com/search?q=nickel+silver+sheet+metal>
I learned to solder sheet metal before I learned to solder wires.

[Frank Krygowski]

Similar to my friction shifters! :-)

--
- Frank Krygowski

[Frank Krygowski]

On 3/11/2022 1:26 AM, John B. wrote:
>
>
> Why fiddle with the paper tape? Just run the machine.

The purpose of the course was to teach Numerical Control programming. In
those days, it was done manually by M codes and G codes.

Of course, if you're making just one fairly simple part, you'd just run
the machine. If you're making millions of a part, you would try to find
ways to automate the process from start to finish. But for production
runs of relatively small size, automatically controlled machine tools
are very valuable, and someone has to know how to program them.


--
- Frank Krygowski

[Frank Krygowski]

The mechanical bits were never a problem. In fact, if you can find a way
to buy one, old machines used only in education can be great values.
Compared to machines used in industry, they typically have very low
hours. Mechanically, the bearings, screws, motors etc. are usually very
good. We just had problems with electronics going bad.

My robotics lab had two fairly small GE (or Nachi) robots. They probably
accumulated less than 75 hours per year, so the only mechanical
maintenance was a few shots of grease. But after they were about 15
years old, they began "forgetting" student programs stored in them. I
had to carefully back up programs after each session. The electronics
repair guys blamed bad capacitors.

>
>> It worked out OK, though. The difficulties ultimately let us convince
>> the administration we needed a brand new Haas mill, plus software to aid
>> in programming it.
>
> If the school has the money, that's usually the best way. It's
> difficult for students to learn on a machine that doesn't work.
> However, when I went to skool (1960's), the situation was different.
> The only machines we could get were donated. You can easily guess
> which machines the schools received.

Yep. Because of work I did for one company, they donated an Adept robot
to our lab. We tried for several years to keep it running, then finally
gave up.


--
- Frank Krygowski

[AMuzi]

+1
To make one, such as building submarines at Groton, you want
a skilled machinist. To make some, tape or basic CNC works
fine, such as small run USA bike parts. Those are often
better made in large quantities by thixoform or forging. To
make things by the millions there are several other
technologies from fully automatic subtractive machining to
heading, sintering, etc.

[John B.]

Yes. I didn't go into details but experience was - say 15 or 20 years
- that most "machine shops" as opposed to Manufacturing Facilities are
making one part, or repairing one part. In fact years ago I had this
same discussion with a chap that ran a 2 machine CNC shop. He made, or
perhaps finished machined, some sort of shaft used in Jet engines. We
finally agreed that no, where your order is, say two or three weeks
work on items that are all exactly the same that a CNC machine was
best while the repair of a 6 foot long shaft in a commercial air
conditioner unit might be cheaper to be done manually.

But I did work with a chap that had two very early "self controlled"
lathes, called "screw machines" which were controlled by metal cams