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ER40 collet chuck on 21" swing Colchester lathe

Overland

Cast Iron
Joined
Nov 19, 2017
I have a 21" x 80" Colchester / Harrison lathe with a 12" chuck.
It's a very large chuck for small diameter work, and high speeds with that chuck makes it hard to concentrate !

So I'm thinking a simple inexpensive option for small work might be an ER40 manual collet chuck.
I was thinking I could turn something that would fit in the the spindle nose, 0.750" per foot, and attach an ER40 chuck to that. The spindle through bore is 3.5". Or perhaps turn the ER40 form on the adapter, and buy a nut.
I believe this taper is considered self-locking, however I'm thinking a draw bar would be a good idea for safety.
Am I being overly cautious ?
Thanks
Bob
 

rblalexander

Aluminum
Joined
Oct 28, 2015
Absolutely use some kind of drawbar. What spindle mount does the machine have?

Sent from my SM-G973F using Tapatalk
 

lucky7

Stainless
Joined
Sep 6, 2008
Location
Canada
If it were me, I’d either have a second smaller lathe for collet work, or a 3J or Pratt Burnerd Multisize (Crawford) set on your bigger lathe. Don’t care for ER on lathe work. I found a good condition Burnerd set for my D1-6 Colchester Triumph 2000, so assume you could get one for a D1-8 or bigger Colchester.

With common hand wheel collet closers on your D1- whatever it is with your size lathe spindle adaptor you don’t need a drawbar which may be an advantage if your headstock is wide.

L7

On edit: found on ebay several Burnerd EC 25 on D1-8 chucks. Up to 2.5” capacity.
 

HappyWyo

Aluminum
Joined
Nov 30, 2019
We have full sets of collets of most types and use them occasionally. However we use our range of Chuck's much more often. We run our American lathes mostly and have from 8" to 32" Chuck's. We run 8" mostly for the same reason you are giving, but change them to 12" regularly. If you go from 12" to collet I think you will be disappointed unless tiny is all you turn.
 

Overland

Cast Iron
Joined
Nov 19, 2017
My spindle nose is D1-11. Pretty big.
I'm fine normally with the 12" chuck, unless I get into small stuff. That's why I was thinking I could use my mill ER40 collects, when I need them.
Not looking for high performance, speed or whatever, just something more appropriate for small stuff at high speed, rather than a 12" chuck.
One other thought I had was a small chuck, but a D1-11 back plate is still about 12" diameter.
Key point is that if I pursue this idea, I should include a drawbar, or tube.
Thanks,
Bob
 

CalG

Diamond
Joined
Dec 30, 2008
Location
Vt USA
My spindle nose is D1-11. Pretty big.
I'm fine normally with the 12" chuck, unless I get into small stuff. That's why I was thinking I could use my mill ER40 collects, when I need them.
Not looking for high performance, speed or whatever, just something more appropriate for small stuff at high speed, rather than a 12" chuck.
One other thought I had was a small chuck, but a D1-11 back plate is still about 12" diameter.
Key point is that if I pursue this idea, I should include a drawbar, or tube.
Thanks,
Bob


ER collets are retained by a nut on the front. No draw bar is needed.

How you might mount the collet nose is up to you. I would use a lathe back plate. It could be a very handy item.IMG_20220126_220943403.jpgIMG_20220126_221016210.jpgIMG_20220126_221040090.jpg

Pics of what I whipped up for the LZ330 Threaded spindle nose (much smaller than your machine) . Also , an ER50 version.

I use the rubberflex collet setup on the L1 spindle nose lathe. That works well at high spindle speeds. (High being 1200 rpm ;-)
 

HappyWyo

Aluminum
Joined
Nov 30, 2019
My spindle nose is D1-11. Pretty big.
I'm fine normally with the 12" chuck, unless I get into small stuff. That's why I was thinking I could use my mill ER40 collects, when I need them.
Not looking for high performance, speed or whatever, just something more appropriate for small stuff at high speed, rather than a 12" chuck.
One other thought I had was a small chuck, but a D1-11 back plate is still about 12" diameter.
Key point is that if I pursue this idea, I should include a drawbar, or tube.
Thanks,
Bob

Ok, I was just thinking about having to put that Chuck on everytime you couldn't use a collet. I know that gets old fast. You need to have a strong back.
 

thermite

Diamond
Joined
Sep 21, 2011
Location
Sol, Terra
Key point is that if I pursue this idea, I should include a drawbar, or tube.

That's wise.

There is another way.

Buy one of those big-ass D1-11 plates.

Put your Machinashitist mojo to work and build a D1-3, D1-4 or common as-dirt SB/Logan and-not-only threaded teat (2 1/4-8, is it?) onto that plate.

One D1-11 plate. Plus "superstructure".

Now you can hunt-up all manner of smaller lathe workholding used-but good or brand-new. Multisize, Rubberflex, 5C, 2J, 2, 4, 6, jaw chucks 4".. and up...

Not just "very slow to swap the goods in"... ER.

Save yer money and try ER on the simple first.

I have one that is a "plate mount" that I can center-up in a 4J chuck.
Or use with a rotab on the mill.

Others I have are on 40-taper, MT tails, and straight tails.

I have ER for just about EVERY spindle under roof.
Solves odd problems, yes. But even so, ER is my LAST RESORT.
"Slow" gave me the motivation to do better. Lots of flavours of "better".

Did I fail to mention ER is slow what with wanting use of a torque wrench (OK.. few bother, but is IS in the spec..) ?

:)

Well,.. ER, TG ,SK, were not meant for competing with a lever or power collet or powered chuck and bar-feed rig handling STOCK..

TOOL holding, and best pre-set off-machine then stuffing a CNC changer's magazine, whole bunch of 'em at a go, or in a "live tool" head, rather.
 
Last edited:

CalG

Diamond
Joined
Dec 30, 2008
Location
Vt USA
Thanks for the good input guys.
Bob

Bob

Not to draw out this idea , but I am having a difficult time visualizing just how one would use a draw tube for ER collets in the way that the C series collets (5C, 3C) are "pulled in" . Whether lever, air, or handwheel actuated.

There are spindle nose front mounted lever actuated collect closers for some collet systems, but that is not what you are speaking of.

I guess in my limited imagination, I don't see how a through the spindle tube puller can benefit an ER collet closing system. Have you ever seen an example? Has anyone?
 

thermite

Diamond
Joined
Sep 21, 2011
Location
Sol, Terra
Bob

Not to draw out this idea , but I am having a difficult time visualizing just how one would use a draw tube for ER collets in the way that the C series collets (5C, 3C) are "pulled in" . Whether lever, air, or handwheel actuated.

It isn't for collet opening or closing operation at all, Cal.

It has been seen prudent as a drawbar keeping the entire master collet from coming OUT of the spindle! Same as my 40-taper fit the mill's drawbar and my MT ERs have threaded MT, not tanged MT.

Opening and closing for stock or tool grip still requires use of a spanner on the hex or castellated NUT at the very nose.

This is why ER is SLOW compared to spring collets such as the (x)C or (x)J series.

We like to have them for ALL spindles as "problem solvers" - holding straight-shank goods we have nothing ELSE that fits and GRIPS as well, at low TIR for example.

I have easily a dozen ER "master" collet HOLDERS (ER 40 and ER 20) on all manner of tails.. plus plate, hex block, and square block.. but only ONE set of good collets, each, of ER 40 and ER 20.

Because I have a LOT of OTHER collet systems (and Weldon-style side locks..) I would usually RATHER use, too.

Also TG-100.. because "Tight Grip" means exactly what it says it means.

Can you spell "tool whore"?

I cannot. Too damned busy hunting more tools....

:D
 

CalG

Diamond
Joined
Dec 30, 2008
Location
Vt USA
Got IT!

Spindle nose taper to ER-40 (X 5MT) adapter draw bolt. Wouldn't be right without one!

I would just use the spindle work depth stop rod, slightly modified to suit the adapter. (supposing a fella had one ;-)

A fella would need something very similar to send down the spindle bore to knock the adapter out anyway.

Personally, on a lathe, I would not consider a collet system that wasn't through bore to be a waste of time and steel.
 

Overland

Cast Iron
Joined
Nov 19, 2017

CalG

Diamond
Joined
Dec 30, 2008
Location
Vt USA
Kind of, Kenton.
The spindle bore is 3.5", with a 0.750 / foot taper in the nose.
My thoughts were a tapered plug, with a through hole of at least 1", and an ER40 collect chuck on "the business end".
I would need to have a tube threaded into this plug, to act as a draw bar, and hold the plug in the taper.
I could use a collet chuck like this one, attached to the plug.
HHIP 3901-5036 ER-40 Collet Chuck, 100 mm Diameter x 42 mm Height: Amazon.com: Industrial & Scientific

That part from amazon is much the same as the unit shown in the pics I had attached in an earlier post.
A "better" execution would be to have an "Adjust-tru" type detail. Nothing being perfect.

Go for a through hole if you are going to do anything. Thank me later ;-)
 

Overland

Cast Iron
Joined
Nov 19, 2017
I found a nice German 135 mm dia 3 jaw chuck I'm going to mount on the "plug", with a tubular drawbar to hold it in place.
A piece of 5-1/2" 1018, 6" long is $80 from my local steel guy. Bet someone's got a piece lying around, lol.
Bob
 

thermite

Diamond
Joined
Sep 21, 2011
Location
Sol, Terra
I found a nice German 135 mm dia 3 jaw chuck I'm going to mount on the "plug", with a tubular drawbar to hold it in place.
A piece of 5-1/2" 1018, 6" long is $80 from my local steel guy. Bet someone's got a piece lying around, lol.
Bob

Two, actually. But in 8620. And a tad more costly.

Slugs to make 3-step PolyVee belt 'cone' pulleys to replace the too-DAMNED-small pitch diameter for legacy Vee belts on my Burke #4 mini-mill.

Did I NEED 8620 'Ordnance Steel' for that?

No.

I'm just congenitally prejudiced!

Dark cutting oil transfusion into my bloodstream, Watertown Arsenal, going like the very hammers of Hell 24 X 6 building the deadly engines of war, 1951

:D
 








 
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