How much hand pressure is 4nm?
Steve(UK)
full arm leverage?
4nm hand tightness is the rather unhelpful advice given in my Thule roof bar
fitting instructions. I don't have a torque wrench, but even if I did I
don't see how I could apply it the tightening of irregular shaped plastic
knobs. These have to be turned to tighten the feet against the car roof (if
you have the Thule "Rapid System" bars you'll understand, I hope)
--
Steve(UK)
pc...@REMOVETHECAPShotmail.com
Malcolm Stewart
geddit?) is pulled downwards by earth's gravity.
(There is a more scientific explanation, but this is the one I remember.)
So 4nm is 4 apples at a radius of 1m, or say about 13 apples at about 1 foot.
So hang a bag of 13 apples on the end of a 12" ruler and that will give you some
idea.
--
M Stewart
Milton Keynes, UK
Steve(UK) <pc...@hotmail.com> wrote in message
news:aaev8h$42k$1...@news5.svr.pol.co.uk...
Guy King
in <aaev8h$42k$1...@news5.svr.pol.co.uk>said....
.
> Is 4nm just a light twist of the wrist or more like gripping hard, using
> full arm leverage?
Well, it's the weight of about four apples on the end of a 1 meter lever!
--
Skipweasel...
Remember, there were people on the Titanic who waved away the sweet trolley.
Guy King
heady air of the shed and in <aaevu7$ttg$1...@news6.svr.pol.co.uk>said....
.
> So 4nm is 4 apples at a radius of 1m,
Bugger, the rays, the rays!
Duncan Wood
"Steve(UK)" <pc...@hotmail.com> wrote in message
news:aaev8h$42k$1...@news5.svr.pol.co.uk...
boo...@hotmail.com
<malcolm...@megalith.freeserve.co.uk> wrote:
>A newton is about the same force as that which an apple (sic; Newton, Apple -
>geddit?) is pulled downwards by earth's gravity.
>(There is a more scientific explanation, but this is the one I remember.)
>
>So 4nm is 4 apples at a radius of 1m, or say about 13 apples at about 1 foot.
>So hang a bag of 13 apples on the end of a 12" ruler and that will give you some
>idea.
>
>--
From my days studying physics 1 Newton is equal to 100 grammes, so
400 grammes force on the end of a 1 metre bar will give you 4nm of
torque at the other end of the bar.
So say about 1.4 kilos of force on a normal sized socked
wrench......not very tight really.
Rachel hall
"Duncan Wood" <free...@dmx512.co.uk> wrote in message
news:aaf27t$vdq$1...@news6.svr.pol.co.uk...
Barry Smith
"Malcolm Stewart" <malcolm...@megalith.freeserve.co.uk> wrote:
> A newton is about the same force as that which an apple (sic; Newton, Apple -
> geddit?) is pulled downwards by earth's gravity.
> (There is a more scientific explanation, but this is the one I remember.)
>
> So 4nm is 4 apples at a radius of 1m, or say about 13 apples at about 1 foot.
> So hang a bag of 13 apples on the end of a 12" ruler and that will give you some
> idea.
I never did get the hang of newtons. Although newtons are a force
rather than a weight, does the above mean that you're taking the
average apple to be 1 / 9.81 of 1kg ? or am I getting confused (again) ?
Barry
--
The internet has had no effect on my life wwwhatsoever.com
Dave Plowman
Barry Smith <b...@g4iat.demon.invalid> wrote:
> I never did get the hang of newtons. Although newtons are a force
> rather than a weight, does the above mean that you're taking the
> average apple to be 1 / 9.81 of 1kg ? or am I getting confused (again) ?
Me neither. But to convert to lbs/ft that most (well, old buggers anyway)
will relate to simply multiply by 0.738.
--
* I'm not a complete idiot, some parts are missing *
Dave Plowman dave....@argonet.co.uk London SW 12
RIP Acorn
Dave Plowman
It works out at about 3 lb/ft. 20 lb/ft is achievable by most with a
large screwdriver.
--
* If you lived in your car, you'd be home by now *
Steve(UK)
This reinforces my feeling that the Thule instructions are pretty unhelpful:
"tighten by hand" can span a wide range of forces. I initially tightened the
aforementioned knobs as much as I could until my grip slipped believing that
roofbars need to be sucured as tightly as possible. This slightly bent the
little plates that hook down under the top of the doors and latch into the
Ford screw holes provided for their own roof racks. No problem until I
removed the bars and then came to re-attach them. Due to the bending, the
angle of the pins that insert into the screw holes had altered so they would
gradually slip out as I tightened the feet. I have now bought a new "fitting
kit" and will try again using much less force. Thule, by the way, were
unhelpful when I e-mailed them --- just an auto responder.
--
Steve(UK)
pc...@REMOVETHECAPShotmail.com
"Dave Plowman" <dave....@argonet.co.uk> wrote in message
news:4b2e301f89...@argonet.co.uk...
Steve(UK)
the car is a Ford Escort 96N 5dr hatchback, and the Thule fitting kit is
number 1004 in their rapid fit range.
Dave Baker
>From: Dave Plowman dave....@argonet.co.uk
>Date: 28/04/02 10:22 GMT Daylight Time
>Message-id: <4b2e301f89...@argonet.co.uk>
>
>In article <aaev8h$42k$1...@news5.svr.pol.co.uk>,
> Steve\(UK\) <pc...@hotmail.com> wrote:
>> Is 4nm just a light twist of the wrist or more like gripping hard, using
>> full arm leverage?
>
>> 4nm hand tightness is the rather unhelpful advice given in my Thule roof
>> bar fitting instructions. I don't have a torque wrench, but even if I
>> did I don't see how I could apply it the tightening of irregular shaped
>> plastic knobs. These have to be turned to tighten the feet against the
>> car roof (if you have the Thule "Rapid System" bars you'll understand, I
>> hope)
>
> It works out at about 3 lb/ft. 20 lb/ft is achievable by most with a
>large screwdriver.
I think you've been at the bursar's Dried Frog Pills again Dave. 20 ft/lbs is a
fair pull on a socket bar or a 13mm spanner and way above what anyone would
manage with a screwdriver. If you doubt me then get a torque wrench, set it to
20 ft/lbs, put a big socket or an impact screwdriver handle on the square drive
and see how far you get trying to make it click. 20ft/lbs is what the rocker
arm nuts on a CVH are done up to and if you think you could do them up (or get
old ones back off again) with a 13mm socket on a screwdriver handle then you're
kidding yourself by about a factor of 4 or 5 I'm afraid.
In the interests of science I just did a little experiment with a socket drive
screwdriver (1" diameter handle) connected at right angles via a small socket
to a 9" long square drive tommy bar. With the other end of the tommy bar
resting on a set of bathroom scales I worked out the torque I could achieve at
the screwdriver handle. White knuckle territory was only 3lbs on the scales i.e
3 x 9/12 = 2.25 ft/lbs.
To simulate a bigger screwdriver handle I put a large socket (42mm o/d) on the
tommy bar and gripped that. That's a nice o/d for a man's hand although the
socket was a bit short to really grip properly. I could hit just over 5lbs on
the scales like that so about 4 ft/lbs. I'm sure that with a properly designed
handle to grip I could go a fair bit over that to 6 or 7 ft/lbs maybe but
nothing like 20.
My little 1/4" drive socket set has a T drive handle with a 4" long arm on it
and I always reckon that 5 ft/lbs is firm hand pressure on that without going
mad. It's about right for sump bolts on CVHs and Pintos and other stuff with
cork gaskets. Alternatively it's what you get with a really short spanner like
a 1/4" or 6mm one with reasonable hand pressure.
So what the OP is after achieving (3 ft/lbs) is a damn good twist on a big
screwdriver or reasonable pressure on a small tommy bar.
Dave Baker
Puma Race Engines (www.pumaracing.co.uk)
Dave Plowman
Dave Baker <pumar...@aol.com> wrote:
> > It works out at about 3 lb/ft. 20 lb/ft is achievable by most with a
> >large screwdriver.
> I think you've been at the bursar's Dried Frog Pills again Dave. 20
> ft/lbs is a fair pull on a socket bar or a 13mm spanner and way above
> what anyone would manage with a screwdriver. If you doubt me then get a
> torque wrench, set it to 20 ft/lbs, put a big socket or an impact
> screwdriver handle on the square drive and see how far you get trying to
> make it click. 20ft/lbs is what the rocker arm nuts on a CVH are done up
> to and if you think you could do them up (or get old ones back off
> again) with a 13mm socket on a screwdriver handle then you're kidding
> yourself by about a factor of 4 or 5 I'm afraid.
I've got a torque screwdriver which goes up to 20 ft/lbs. I've never used
this setting - but assumed it was possible. So I'll bow as usual to your
superior experience. ;-)
--
* Always borrow money from pessimists - they don't expect it back *
Dave Baker
>Message-id: <4b2e3f1562...@argonet.co.uk>
>
>In article <20020428070050...@mb-cd.aol.com>,
> Dave Baker <pumar...@aol.com> wrote:
>> > It works out at about 3 lb/ft. 20 lb/ft is achievable by most with a
>> >large screwdriver.
>
>> I think you've been at the bursar's Dried Frog Pills again Dave. 20
>> ft/lbs is a fair pull on a socket bar or a 13mm spanner and way above
>> what anyone would manage with a screwdriver. If you doubt me then get a
>> torque wrench, set it to 20 ft/lbs, put a big socket or an impact
>> screwdriver handle on the square drive and see how far you get trying to
>> make it click. 20ft/lbs is what the rocker arm nuts on a CVH are done up
>> to and if you think you could do them up (or get old ones back off
>> again) with a 13mm socket on a screwdriver handle then you're kidding
>> yourself by about a factor of 4 or 5 I'm afraid.
>
> I've got a torque screwdriver which goes up to 20 ft/lbs. I've never used
>this setting - but assumed it was possible. So I'll bow as usual to your
>superior experience. ;-)
It has got me thinking a bit though which only goes to show that there is never
a shortage of things to fritter away ones mental energy on. It's a bit
disappointing to twist away as hard as you can on a screwdriver handle and see
the dial on the bathroom scales hardly move. It makes more sense if you slice
the numbers a different way though.
The screwdriver handle in my first test was 1" in diameter so 0.5" radius. That
means to achieve a torque of 20 ft/lbs on it I'd have to generate 24 x 20 or
480 lbs shear force between the skin of my hand and the handle. I'm wondering
how much force it takes to peel the skin off the palm of your hand but I reckon
if you superglued your palm to a wall and tried to hang off it with another two
blokes hanging on your legs it wouldn't be a happy outcome.
Even the 2.25 ft/lbs I managed on that handle was a force of 54 lbs at the rim.
That was enough to start to bruise my palm on the ridges on the handle. The
3.75 ft/lbs I managed on the bigger (42mm o/d) handle turns out to be almost
exactly the same shear force now I work it out. Using a socket bar or spanner
gives you A) lots of leverage and B) the skin on your hand is operating in
compression rather than shear which is immensely more pleasant.
I know how much force it takes to peel the skin off your foot though because I
once tried to play a game of squash barefoot after forgetting to take my
trainers. The first drop shot my opponent played in a front corner made me run
and then stop dead when I reached it. As I slammed my front foot down to play
the shot the skin on the sole of it certainly stopped dead against the wooden
floor but sadly the rest of the foot with me attached to it kept moving. As I
slid into the court wall leaving a trail of blood and skin on the floor behind
me I decided that shoes have more to commend them than perhaps we immediately
realise.
The largest diameter my hand at least (not very big hands) can comfortably grip
is about 3". Applying the 54 lbs I generated on the smaller handle means I
suspect an upper limit for the torque I could comfortably generate in twist on
an optimally sized handle is about 7 ft/lbs.
Maybe an adult male silverback gorilla could use the full range of your torque
screwdriver but I reckon the only way you or I would manage it would be to
drill a hole in the handle and stick a tommy bar through it :)
Guy King
in <aagk2m$2vj$1...@news8.svr.pol.co.uk>said....
.
> "tighten by hand" can span a wide range of forces.
I just bust an Ikea garlic crusher. When I took it back they looked at
me (6'2", 20 stone) and said "You've been using hand pressure, haven't
you?"
Barry Smith
Dave Plowman <dave....@argonet.co.uk> wrote:
> In article <9c9b042...@g4iat.demon.co.uk>,
> Barry Smith <b...@g4iat.demon.invalid> wrote:
> > I never did get the hang of newtons. Although newtons are a force
> > rather than a weight, does the above mean that you're taking the
> > average apple to be 1 / 9.81 of 1kg ? or am I getting confused (again) ?
>
> Me neither. But to convert to lbs/ft that most (well, old buggers anyway)
> will relate to simply multiply by 0.738.
That's handy to know. Thanks.
Malc
> Me neither. But to convert to lbs/ft that most (well, old buggers anyway)
> will relate to simply multiply by 0.738.
Who are you calling a bugger
Malc
Steve Leech
the limit with aluminium and steel box sections and I've also found that the
little steel hook plates supplied do bend easily if they are overtightened.
I have since had a new set made by my local engineering firm who made them
from stainless steel before I had them powder coated to protect the
paintwork. I can now tighten them to maximum hand pressure on the the end
knobs without them bending and stopping the doors from closing.
"Dave Baker" <pumar...@aol.com> wrote in message
news:20020428111647...@mb-ms.aol.com...
Dave Plowman
Malc <malXX...@blueyonder.co.uk> wrote:
> > Me neither. But to convert to lbs/ft that most (well, old buggers
> > anyway) will relate to simply multiply by 0.738.
> Who are you calling a bugger
If the cap fits...
--
*I finally got my head together, now my body is falling apart.