Low speeds - any disadvantages?
Dave H.
but...
About to arrange a trip to the next town to look at a medium-sized lathe
(English, geared head 6.5/13" x 40", 20" into gap although the spindle
bore's too small for e.g. fork stanchions, has a non-working suds pump and
tank etc.) and may consider it if it's in reasonable shape, one concern is
the speed range - 8 speeds from 30 - 750 RPM - and whether the low top speed
is going to cause problems? The only issue I can think of (other than slow
removal of material when cutting!) is that may be a bit slow for
small-diameter work in work-hardening materials, but as this would be my
first lathe since college over 30 years ago any hints and tips would be
appreciated!
Another concern is that the quadrant lever and clutch knob for the sliding
and cross power feeds (ooh, luxury....) appear to be missing - I've a fair
idea how they (should) work and aptitude enough to rebuild car and 'bike
gearboxes, so is this going to be a serious can of worms should there be
problems with 'em? They were manufactured into the 70's and fairly popular
(if a bit pricey new...) and had spares support into the 90's so there may
be spares still around... Famous Last Words?
As manufactured it's Imperial, and bikes seem to all be Metric these days -
apart from threading (which may need a 127 gear or similar made if it has
gone missing over the last 50 years), am I making a rod for my own back by
not going for a Metric lathe? I have a bunch of Metric (and Imperial)
measuring tools and can probably remember 40 thou = 1 mm...
I should be able to see/hear it running so can check for noisiness and slop
in the bearings, head, QC 'box etc., and I'll be able to check the ways and
see what tooling's with it, anything else that I should be checking? Apart
from how much trouble I'm going to get from SWMBO, of course...
Thanks in advance,
Dave H.
--
(The engineer formerly known as Homeless)
"Rules are for the obedience of fools, and the guidance of wise men" -
Douglas Bader
Bob Minchin
Bit too slow for carbide tooling on small diameters but fine for HSS
Is it a three phase machine? if so you could run it on an inverter and
run it up to double the speed without much risk. Keep any eye on top
speed for the big chucks etc and see if the bearings/gearbox warms up
too much.
Start remembering that 1mm = 39.37 thou as you home in on final diameters.
These slightly bigger machines tend to be cheap as some home users are
(wrongly) put off by them.
Unless it has been abused then it should be fine.
Good luck
Bob
Mark Rand
<hopefuldave_does...@hotmail.com> wrote:
> any hints and tips would be
>appreciated!
>
Might be easier if you could tell us what lathe it is (make/model). Then
people may be able to offer suggestions of weak or strong points from personal
experience.
Regards
Mark Rand
RTFM
Dave H.
"Mark Rand" wrote...
>
> Might be easier if you could tell us what lathe it is (make/model). Then
> people may be able to offer suggestions of weak or strong points from
> personal
> experience.
>
Good Idea...
It's a post-war (WW2, not the Great War!) Milnes 13", popping out to look at
it in a few mins... NOT buying it while I'm there, need to see if it'll fit
in the shed first!
Thanks,
Dudley Simons
One small detail - how much do they want for it and how much will it
cost you to move it?
Dave H.
"Dudley wrote...
> One small detail - how much do they want for it and how much will it cost
> you to move it?
They'll deliver at cost (having big wagon and being all of 8 miles
away...) - and a reserve of �200 on it, which ain't bad if it's all there
and working! Just off to see if it is.... And whether it'll fit in the shed
:)
Don Foreman
<hopefuldave_does...@hotmail.com> wrote:
My lathe has speeds up to 1000 RPM in "low range" and up to 2000 in
high range -- but the high range doesn't work (RPC too small to start
it) and I've not missed it in over 10 years of use. I very rarely
use the 1000 rpm setting.
basilisk
"Dave H." <hopefuldave_does...@hotmail.com> wrote in message
news:Jmdcn.36646$En7....@newsfe07.ams2...
to increase
the motor sheave size or even drive the motor with a vfd.
I'm not familiar with this particular lathe but one other concern might be
the minimum
feed speed, some of the older slow lathes wouldn't feed less than .010",
(even much more in big machines) , it may be tedious to do fine finish work.
YMMV, and for the price it would still be a good deal.
basilisk
Karl Townsend
> My lathe has speeds up to 1000 RPM in "low range" and up to 2000 in
> high range -- but the high range doesn't work (RPC too small to start
> it) and I've not missed it in over 10 years of use. I very rarely
> use the 1000 rpm setting.
Don, I'm surprised. For the small parts with perfect finish that you make,
I'd frequently be up to the top 4000 rpm on my 10EE or 4500 rpm on my CHNC.
I stayed at lower rpm for years till "the kid" taught me to "run that
machine". He was used to having 10K at his disposal.
Karl
Peter Neill
<hopefuldave_does...@hotmail.com> wrote:
When I had a Myford ML7 - top speed of 640 rpm - I still managed to
use carbide and turn small parts. A number of 1mm x 5 long silver
steel pins and a 4mm 316 shaft were no problem, although the final
finish was with a bit of emery.
At the time I used a DCMT tool from Greenwood with IIRC Sandvik
GC1025 grade inserts, with a 0.2mm nose radius. Very versatile tool
which then became my almost universal choice for anything on the
Myford.
Even now on my Colchester Bantam I rarely go above 1000rpm (next and
top speed is 1600) and use carbide for everything except form tools.
Robert Swinney
"My lathe has speeds up to 1000 RPM in "low range" and up to 2000 in
high range -- but the high range doesn't work (RPC too small to start
it) and I've not missed it in over 10 years of use. I very rarely
use the 1000 rpm setting."
Jeeze, Don. Sorry! My 2 HP lathe goes to 2000 rpm, but like you, I rarely ever use the higher
speeds. My RPC starts it with no problem, however. You want me to refer you to some good articles
on proper RPCs? (:>) . . . or however you make the "grin" symbol .
Bob Swinney
Dave H.
"basilisk" wrote...
>
>>
> The slow speed will be of a concern with small parts, but it may be
> possible to increase
> the motor sheave size or even drive the motor with a vfd.
>
> I'm not familiar with this particular lathe but one other concern might be
> the minimum
> feed speed, some of the older slow lathes wouldn't feed less than .010",
> (even much more in big machines) , it may be tedious to do fine finish
> work.
> YMMV, and for the price it would still be a good deal.
>
On investigation of the plate on the machine, the sliding (carriage?) feeds
run from 2 thou/rev upwards, the surfacing (cross-slide?) from 0.7 thou (but
see below) - I assume this should be OK for most purposes, can't imagine
having tools with much less of a tip radius!
I like the VFD idea, although it's fitted with what looks to be a 2HP 240v
motor - I guess that could be driven with a single-phase VFD if such a thing
exists?
I went to take a look this evening, the ways look to be in pretty good order
and there weren't any really offensive noises - the head and QC gears all
looked pretty good (no chipped/missing teeth, not particularly worn) - the
spindle bearings *might* be a little sloppy, but it appears to have taper
rollers there so it could be just a matter of getting the preload right?
Certainly when the clutch was disengaged it took a fair few seconds to spin
back down from 120 rpm or so (with a hefty 10" 3-jaw chuck on it), so not
on the tight side :o) It looks like as a minimum the 127 tooth gear's there,
along with 3-jaw, faceplate, tailstock chucks and centres, plus an
assortment of tools/bits, holders and the thread-dial: There is a problem
with the feed selection lever / clutch though, but it looks like all the
bits are there to work with, and the steadies have disappeared in to the
same black hole as the handbook and the 4-jaw chuck...
It's a bit bigger than I was expecting - New Shed time, perhaps
It's starting to look like I may have to buy a *big* bunch of roses (and a
bigger bottle of bubbly) for Sunday, and promise SWMBO that her trike will
be one of the first projects... Aaaaarghhh.
Thanks for the input,
Jon Elson
> Not strictly model engineering (motorbike engineering and supercharging!),
> but...
>
> About to arrange a trip to the next town to look at a medium-sized lathe
> (English, geared head 6.5/13" x 40", 20" into gap although the spindle
> bore's too small for e.g. fork stanchions, has a non-working suds pump and
> tank etc.) and may consider it if it's in reasonable shape, one concern is
> the speed range - 8 speeds from 30 - 750 RPM - and whether the low top speed
> is going to cause problems?
massive limitation, but many times for smaller work you might want more.
It may be possible to run this machine well above rated speed with a VFD
on the motor. Depending on the bearings, lube system and such, you may
be able to do this safely, or not.
The only issue I can think of (other than slow
> removal of material when cutting!) is that may be a bit slow for
> small-diameter work in work-hardening materials, but as this would be my
> first lathe since college over 30 years ago any hints and tips would be
> appreciated!
>
> Another concern is that the quadrant lever and clutch knob for the sliding
> and cross power feeds (ooh, luxury....) appear to be missing - I've a fair
> idea how they (should) work and aptitude enough to rebuild car and 'bike
> gearboxes, so is this going to be a serious can of worms should there be
> problems with 'em? They were manufactured into the 70's and fairly popular
> (if a bit pricey new...) and had spares support into the 90's so there may
> be spares still around... Famous Last Words?
or, missing, as in, this lathe never had any power feeds other than the
main carriage threading feed?
>
> As manufactured it's Imperial, and bikes seem to all be Metric these days -
> apart from threading (which may need a 127 gear or similar made if it has
> gone missing over the last 50 years), am I making a rod for my own back by
> not going for a Metric lathe? I have a bunch of Metric (and Imperial)
> measuring tools and can probably remember 40 thou = 1 mm...
>
for every threading pass will drive you round the bend! The transposing
gears get you proper feeds, but with an imperial leadscrew, you cannot
disengage the leadscrew between passes.
Jon
Peter Fairbrother
> If you are going to be doing a lot of metric threads, having to back up
> for every threading pass will drive you round the bend!
I usually do that as standard practice.
You have to withdraw the cutter anyway, and running for a second or so
in reverse is not significantly harder than winding the carriage handle
- and then you don't have to bother with the thread dial indicator at all :)
-- Peter Fairbrother
Bob Minchin
suitable.
Bob
Chillybilly
Harrison 11" top speed 800 with a pulley mod ,can get down as low as
about 1.5mm dia in most stuff but it can be frustrating at times ,so
go pick up one of thise micro lathes from Arc euro ,strip it sort it
and it will be nicely under the bench ready for that carb jet or silly
size pin that will inevitibly be required.
I have no connection with arc euro .
As to metric /imperial question i have an imperial mill and a metric
lathe so i just have to be careful somtimes ,reckon its quite good to
be able to do stuff in either size ,certainly the way they trained us
when i did my time ,enjoy your big iron !!
DoN. Nichols
> Not strictly model engineering (motorbike engineering and supercharging!),
> but...
>
> About to arrange a trip to the next town to look at a medium-sized lathe
> (English, geared head 6.5/13" x 40", 20" into gap although the spindle
> bore's too small for e.g. fork stanchions, has a non-working suds pump and
> tank etc.) and may consider it if it's in reasonable shape, one concern is
> the speed range - 8 speeds from 30 - 750 RPM - and whether the low top speed
> is going to cause problems? The only issue I can think of (other than slow
> removal of material when cutting!) is that may be a bit slow for
> small-diameter work in work-hardening materials, but as this would be my
> first lathe since college over 30 years ago any hints and tips would be
> appreciated!
Hmm ... for really small-diameter work (as long as you don't
need to thread with it) maybe a small lathe like a Taig/Peatol or a
Sherline in addition to the more serious sized one which you are
contemplating. Granted, that top speed is going to be a trial on your
patience. I'm surprised that you don't get up to about 1600 RPM on a
12" or 13" swing.
> Another concern is that the quadrant lever and clutch knob for the sliding
> and cross power feeds (ooh, luxury....) appear to be missing - I've a fair
> idea how they (should) work and aptitude enough to rebuild car and 'bike
> gearboxes, so is this going to be a serious can of worms should there be
> problems with 'em? They were manufactured into the 70's and fairly popular
> (if a bit pricey new...) and had spares support into the 90's so there may
> be spares still around... Famous Last Words?
It depends on how much is missing, and what the design is. If
you know the maker, you can check it out on <http://www.lathes.co.uk>
and perhaps get an idea just how they work on that particular machine.
If it just the star shaped nuts like South Bend uses, and nothing from
under them is missing you probably can do fairly well. If you have to
make a stack of clutch plates, it may be a bit more tricky.
> As manufactured it's Imperial, and bikes seem to all be Metric these days -
> apart from threading (which may need a 127 gear or similar made if it has
> gone missing over the last 50 years), am I making a rod for my own back by
> not going for a Metric lathe? I have a bunch of Metric (and Imperial)
> measuring tools and can probably remember 40 thou = 1 mm...
Hmm ... actually, 39.37.... (repeating out after some decimal
places). The easier one for me to remember is the totally precise
25.4mm/inch. Calculate using that, and you are there. It is totally
precise because of a standards definition back in the 1950s IIRC.
And for real convenience, check out the digital calipers and
micrometers. You can switch between systems at the press of a button,
including converting an already made measurement.
As for the metric threading, even with the 127 tooth gear, you
have to remember that the half-nuts have to be kept engaged until you
have the thread completed, and you need to run the lathe backwards to
get to the starting position for the next pass. If you disengage the
half nuts, you will almost certainly wind up cutting along a different
path each pass.
> I should be able to see/hear it running so can check for noisiness and slop
> in the bearings, head, QC 'box etc., and I'll be able to check the ways and
> see what tooling's with it, anything else that I should be checking? Apart
> from how much trouble I'm going to get from SWMBO, of course...
Sounds like you have a pretty good handle on it.
Good Luck,
DoN.
--
Email: <dnic...@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
Martin H. Eastburn
More power in low gear and lower power in high.
Power - really torque or the ability to cut without a stall.
Large diameter requires lower speeds - it is surface speed not rpm
that determine rpm and cutter and material.
Martin
DoN. Nichols
>
>>
>> Might be easier if you could tell us what lathe it is (make/model). Then
>> people may be able to offer suggestions of weak or strong points from
>> personal
>> experience.
>>
>
> Good Idea...
>
> It's a post-war (WW2, not the Great War!) Milnes 13", popping out to look at
> it in a few mins... NOT buying it while I'm there, need to see if it'll fit
> in the shed first!
O.K. That looks like an intersting machine, based on the
description in <http://www.lathes.co.uk>. And it looks as though the
spindle bore (1-5/8") is large enough so you could adapt a 5C collet
closer to it.
Aha! Hardened bed too. Probably in pretty good shape then,
unless it has been used for toolpost grinding without sufficient protection.
DoN. Nichols
>>
>>>
>> The slow speed will be of a concern with small parts, but it may be
>> possible to increase
>> the motor sheave size or even drive the motor with a vfd.
>>
>> I'm not familiar with this particular lathe but one other concern might be
>> the minimum
>> feed speed, some of the older slow lathes wouldn't feed less than .010",
>> (even much more in big machines) , it may be tedious to do fine finish
>> work.
>> YMMV, and for the price it would still be a good deal.
>>
>
> On investigation of the plate on the machine, the sliding (carriage?) feeds
> run from 2 thou/rev upwards, the surfacing (cross-slide?) from 0.7 thou (but
> see below) - I assume this should be OK for most purposes, can't imagine
> having tools with much less of a tip radius!
O.K. My 12x24" Clausing will produce even finer feeds -- but I
don't think that I've ever used them. :-)
> I like the VFD idea, although it's fitted with what looks to be a 2HP 240v
> motor - I guess that could be driven with a single-phase VFD if such a thing
> exists?
I'm afraid not. Single-phase motors are quite frequency
sensitive, because the value of the starting capacitor has to be tuned
to the line (mains) frequency and the inductance of the motor windings.
And a single-phase motor typically has a centrifugal switch which will
re-engage the start capacitor when the speed drops below a certain
point.
What are the odds of finding a three-phase motor which will fit
it?
> I went to take a look this evening, the ways look to be in pretty good order
> and there weren't any really offensive noises - the head and QC gears all
> looked pretty good (no chipped/missing teeth, not particularly worn) - the
> spindle bearings *might* be a little sloppy, but it appears to have taper
> rollers there so it could be just a matter of getting the preload right?
> Certainly when the clutch was disengaged it took a fair few seconds to spin
> back down from 120 rpm or so (with a hefty 10" 3-jaw chuck on it), so not
> on the tight side :o) It looks like as a minimum the 127 tooth gear's there,
> along with 3-jaw, faceplate, tailstock chucks and centres, plus an
> assortment of tools/bits, holders and the thread-dial: There is a problem
> with the feed selection lever / clutch though, but it looks like all the
> bits are there to work with, and the steadies have disappeared in to the
> same black hole as the handbook and the 4-jaw chuck...
All in all, it sounds like a nice deal.
> It's a bit bigger than I was expecting - New Shed time, perhaps
It is worth it. :-)
> It's starting to look like I may have to buy a *big* bunch of roses (and a
> bigger bottle of bubbly) for Sunday, and promise SWMBO that her trike will
> be one of the first projects... Aaaaarghhh.
Very much so.
Good luck,
Ned Simmons
<hopefuldave_does...@hotmail.com> wrote:
> - the
>spindle bearings *might* be a little sloppy, but it appears to have taper
>rollers there so it could be just a matter of getting the preload right?
What makes you think the bearings are sloppy? If they're not making
nasty noises at top speed they're most likely OK. The preload is
controlled by precision spacers and almost certainly not adjustable.
--
Ned Simmons
Don Foreman
I use what I have. I'm not in a hurry, production is not an issue. I
could get up to 2K RPM just by finding a 10HP idler, but I've not been
motivated to do it.
Don Foreman
No articles needed, Bob. The lathe is 3 HP in "low range", 5HP in
"high range". The 5 HP idler works fine in low range but can't wind
up the lathe in high range before the circuit breaker in the lathe
pops.
How you could help: rather than articles, send me a 10 HP idler and
someone to move the hundreds of lb of raw stock and rack that's in
front of the present idler, intall the new idler (next to the old
one), check it all out and put everything back.
Don Foreman
wrote:
That doesn't bother me a bit, Jon. I often back up even when cutting
inch threads. The threads I cut are usually short, often fine, and
it's as easy to change speeds (gear head lathe) as it is to hit the
right spot on the threading dial. I cut slow so I can stop in time,
back up fast. I've found it works best for me to do it once slowly
rather than thrice quickly get it right third try, since I very seldom
make more than two or three of anything.
Carbide cutters work best at higher speeds, HSS works well at lower
speeds. HSS can take a keener edge than most carbide. I can take
finish cuts of tenths with HSS that produce fuzz or dust rather than
chips. Carbide won't do that, at least not for me. I don't understand
a preference for carbide in a home shop where production isn't an
issue. It's useful when working with hard or abrasive materials, but
for ally, brass, bronze, delrin, nylon, mild steel and some stainless
I much prefer HSS. I often run it dry or with just a few drops of
cutting fluid, still get good surface finish with sharp,
carefully-ground bits.
I have never made anything thatcouldn't be made on a 9 or 10 inch
Logan or South Bend or even a Myford Super 7, but what I have is a
15x50 import clone of a gearhead Colchester or Clausing that belonged
to Mary's dad. Her mom wanted me to have it when he passed because
she thought I might appreciate and respect it as he did. She was
right. The difference in rigidity between it and the smaller lathes is
huge and I like that a lot. Chatter? What's that? I could probably
love a Monarch 10EE or Hardinge a lot, but I'm not in shop-building
mode and I'm quite content with what I have.
I'm retired now, but these attitudes were formed when my shop time was
as limited as that of most guys with a full-time job and a family.
Shop time was relaxation, a respite from the competitive race and
daily grind of bidness. Production efficiency has never been an
objective in my shop. On my time, having fun is job 1.
Dave Baker
"Dave H." <hopefuldave_does...@hotmail.com> wrote in message
news:Jmdcn.36646$En7....@newsfe07.ams2...
> but...
>
> About to arrange a trip to the next town to look at a medium-sized lathe
> (English, geared head 6.5/13" x 40", 20" into gap although the spindle
> bore's too small for e.g. fork stanchions, has a non-working suds pump and
> tank etc.) and may consider it if it's in reasonable shape, one concern is
> the speed range - 8 speeds from 30 - 750 RPM - and whether the low top
> speed is going to cause problems? The only issue I can think of (other
> than slow removal of material when cutting!) is that may be a bit slow for
> small-diameter work in work-hardening materials, but as this would be my
> first lathe since college over 30 years ago any hints and tips would be
> appreciated!
My Student has a top speed of 1200 I think it is but because I run it off a
phase converter it's not too happy at starting up on the highest speeds. 900
is ok but I actually rarely run it at more than 650 and don't find that to
be any sort of restriction. In high volume production you want the optimum
speed for maximum metal removal but for odd jobs and home shop work most
things will cut just as happily at lower speeds with sharp tooling for the
sake of a few more seconds per job.
I always find the key is the right tooling. I use razor edged non ferrous
carbide tips even for ferrous work because they cut better on small
machines. Maybe for the occasional roughing job I'll use an actual ferrous
tip but you can't get any sort of finish with them.
If the lathe is suitable otherwise I wouldn't give the top speed a second
thought.
--
Dave Baker
Robert Swinney
"Don Foreman" <dfor...@NOSPAMgoldengate.net> wrote in message
news:m8j4n59q2rfo1fvav...@4ax.com...
Robert Swinney
"No articles needed, Bob. The lathe is 3 HP in "low range", 5HP in
"high range". The 5 HP idler works fine in low range but can't wind
up the lathe in high range before the circuit breaker in the lathe
pops.
How you could help: rather than articles, send me a 10 HP idler and
someone to move the hundreds of lb of raw stock and rack that's in
front of the present idler, intall the new idler (next to the old
one), check it all out and put everything back."
Point well taken, Don. Hey! I still plan on coming up to see you when the Delta Queen gets running
again. At that time I will be happy to help you move all the raw stock, rack and etc. that's in
front of your idler. In the mean time, your under powered idler's performance could possibly be
improved by the judcious addition of some capacitors. Remember all the discussions re. idler, load
motor, and interconnections comprising a network?
Resp,
Bob Swinney
Bob Engelhardt
lathes with modest high speeds and who don't feel it's a problem.
I have a 10 x 24 Jet with a max speed of 2200 rpm +-. I have a
controller for it that takes the FPM desired and the diam, and drives
the VFD to give the right speed. I often find the the controller wants
the spindle to go faster than 2200. In ordinary circumstances, e.g.,
mild steel & 1/2" diam. Such that I was considering re-pulleying it to
get higher speeds (if the spindle bearings would be OK with it).
My assumption has been that the FPM is not just a matter of efficiency
(i.e., production speed), but of surface finish. That too low FPM will
produce a worse finish than a higher "right" value. Am I wrong? Is FPM
just a max value to keep production up without destroying the tool?
As always I'm sure that the vast collective knowledge here will have the
answer,
Bob
Don Foreman
I've found that carbide produces a better finish at higher speeds, but
I get good finish with HSS at any speed. Last week I made a pin with
0.100" dia running at 640 RPM, this to repair a toy for the little boy
next door.
Don Foreman
When you get here, let's just enjoy the day. Winter is shop season.
Karl Townsend
> When you get here, let's just enjoy the day. Winter is shop season.
Man, I must have things all messed up. I think winter is fishin' season.
Shop days are rainy days or too hot days or any day I need something.
Karl