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Schutzhund
04-08-2006, 04:34 PM
How would one go about using collets in an MT4 lathe spindle for small part turning? Is this even possible? If so what do I need?

I have searched through books, catalogs and all over the web with no luck finding what I need.

Please excuse me if this is a stupid question with an easy answer, but I am totally lost on this subject.

I am *thinking* this could be done with a drawbar and some kind of collet adapter. How far off am I?

John Foster
04-08-2006, 04:50 PM
As I recall, the 13" South Bend, and others, used a 4C collet and an adapter with drawbar. Adapter easy to make, 4C collets are around. John

John Foster
04-08-2006, 04:55 PM
I tried to edit but must have missed a step. So, how do I do it?

In my opinion, the only stupid questions are the ones you don't ask. John

Second try; Schutz--- says click save. Trying iy now. Thanks.

And it works. As I said, the only stupid question is the one you don't ask. I asked and learned. John

big-dipper
04-08-2006, 05:04 PM
This shows a lever type collet closer.
http://tinyurl.com/jyd92
There are also handwheel types that are much simpler, cheaper, and adaptable to different machines. I found a used handwheel type collet closer manufactured by Royal Products to fit my 13" SBL. You'll have to look a bit to find one, but they are around.

vinito
04-08-2006, 05:09 PM
Yes it can be done.
The most convenient and frugal collet setup* is 5C. Since they are so common you can find them pretty cheap. However, Morse 4 is too small to work on 5C with a drawtube so you're stuck with finding a 5C collet chuck that fits your spindle.

4C collets are less common so harder to find, but will function in a Morse 4 spindle with a drawtube. The MT4 to 4C adapters are pretty rare, but it could be home-made fairly easily as long as you're comfortable turning tapers. If you ran across a bunch of collets sometime, that would be a pretty slick way to go, but the relative scarcity of 4C collets is a significant factor. You'd probably have to count on making both the nose adapter and drawtube yourself.

*actually a more frugal collet setup is some kind of ER collet arrangement. Due to their design each collet has a very wide range of sizes it will grip, so it only requires a handful of collets to cover a wide range of sizes. The biggest potential problem with it though is you'd have to make the thing from scratch (adapt an ER collet holder to mount to your lathe) since ER collet chucks that mount right to the lathe have, curiously, never been manufactured as far as I know. You could always just buy a regular ER collet holder and chuck it in a 3- or 4-jaw chuck easily.
Also, the Jacobs flex collet system works similarly, was built in many versions to mount right up to many lathe spindles, and can be found on eBay frequently for $350 or less. 11 collets holds any stock from 1/16" to 1-3/8" diameter.

One more factoid: ER and Jacobs flex-collets grip a wide range, but require that the stock be long enough to extend almost all the way through the collet to function correctly, and are only for round stock. 5C collets grip a very small range (+.000/-.003" or so) but they can hold very short parts, i.e. the head of small bolts for turning the threads. Also, 5C collets are made that fit square, hex, and maybe other shapes of stock. Consider this against your needs when deciding, or just get both :D

I have a Jacobs collet chuck on my MT4 lathe and I use it (and like it) a lot. I've used 5C collets on a few lathes with collet chucks, as well as lathes that had a 5C nose and I like them both a lot too. Just depends on what you're working on.

$.02

John Stevenson
04-08-2006, 05:24 PM
*actually a more frugal collet setup is some kind of ER collet arrangement. Due to their design each collet has a very wide range of sizes it will grip, so it only requires a handful of collets to cover a wide range of sizes. The biggest potential problem with it though is you'd have to make the thing from scratch (adapt an ER collet holder to mount to your lathe) since ER collet chucks that mount right to the lathe have, curiously, never been manufactured as far as I know.

See here, 4th item down.

http://www.arceurotrade.co.uk/en-gb/dept_205.html

Timleech
04-08-2006, 05:54 PM
See here, 4th item down.

http://www.arceurotrade.co.uk/en-gb/dept_205.html


Or even

http://www.arceurotrade.co.uk/en-gb/dept_216.html

well down the page, MT3/ER32 chuck & collets. I have an MT4 version, made by Bison IIRC. you might need a drawbar for security.

Tim

Schutzhund
04-08-2006, 06:05 PM
Wow! Thanks guys!

Venito, awesome post! Very informative. Thanks!

For those who may later stumble upon this post, I found a lot of information about collets here:

http://www.cox-internet.com/drspiff/machining/collets/Collets.htm#Morse%20Taper

And here:

http://shopswarf.orcon.net.nz/collet.html

And a "HOW TO" article on Using R8 Collets in a 4C Spindle

Bottom of this page:

http://72.14.203.104/search?q=cache:_kRBpt28YAkJ:www.homemetalshopclub. org/news/jul04/jul04.html+4C+collet&hl=en&gl=us&ct=clnk&cd=1

Schutzhund
04-08-2006, 06:14 PM
I tried to edit but must have missed a step. So, how do I do it?

In my opinion, the only stupid questions are the ones you don't ask. John
Did you click "Save" after editing your post?

lane
04-08-2006, 11:14 PM
Grand tool has all the 4-c collets any one could wont.

TGTool
04-09-2006, 12:44 AM
ER Collet adapters to threaded spindles are not that hard to make. I have made a number of them in connection with my business, mostly 1-1/2 - 8 for ER-32, but I've made other threads and ER-40 adapters. If you have more time than money you can do the whole thing. If you have more money, less time, or more trepidation about your machining skills buy the closing nut as a standard replacement from any of the industrial suppliers and only machine the body yourself.

I'll be at NAMES with both kits and finished collet adapters at the Tallgrass Tools table.

Jan M.

J Tiers
04-09-2006, 01:53 AM
That link from JS appears to be incompatible with Mozilla, so I couldn't see it.

But, most ER holders don't let you pass stock thru the collet (I understand some do).

IMO that is an unacceptable limitation. Even if you don't think so now.... you will later.

You can, however, pretty easily make your own accurate closer for any size collet you choose that will fit in the taper. Even a smaller one, like 3AT or 3C, etc. Not fitting a 5C is a pain, because 5C are the cheapest collets on earth, if you don't need consistently super accurate ones. But, you use whatcha got.

Because that 4MT is the spindle you have, it's easy as anything to set your compound to the correct angle, using a DTI. Then you are set to make any sort of spindle-mounted tooling you choose to.

I would turn the taper between centers first, then put in the spindle, bore for collet body, and turn the correct closer angle. Mark the relative position in teh spindle and whenever you put it back that same way, you should be almost perfectly accurate, as good as your turning is.

Making a drawtube is easy enough. I'd advise using a piece of pipe, with an attached piece (braze or solder) that is threaded, made of some decent steel. Pipe threads poorly for finer threads, IME. A simple handwheel, bushing for the spindle, and you are off and running, all you need are the collets.

Timleech
04-09-2006, 05:39 AM
That link from JS appears to be incompatible with Mozilla, so I couldn't see it.


I get a message with Firefox saying it has stalled, if I choose the 'continue' option it completes successfully.



But, most ER holders don't let you pass stock thru the collet (I understand some do).



That's where the chuck to which Sir John posted the link *ought* (I haven't seen one) to win out over the MT3 or MT4 chuck.

Tim

John Stevenson
04-09-2006, 05:56 AM
OK,
Crap aweful picture, just a screen grab but I'll dig one out later and take a pic.

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/ercolletchuck.jpg

With this type there is no limit to what goes thru the spindle except for the max collet size or spindle bore and no gaps in the range.

The collets also double up as work holding and tool holding, something that other collets don't do.

Ever seen an R8 in a lathe spindle nose or a 5C in a mill spindle holding a cutter ?

That little ER11 chuck is interesting, I'll also post a pic later of a mod I've done to one of these to make it more versatile.

JCHannum
04-09-2006, 09:35 AM
I also support the 5C collet over the ER for its intended application.

The ER collets are available in a wide range of sizes, but to cover the range of the 5C, one will need a set of ER16, and ER50. The cost of two new ETM sets is around $1200. Imports are available for about 2/3 of that price, but their quality and accuracy is questionable. Collet chucks are not available for most lathe spindles in these sizes, but let's guess that you might be able to cobble up something for $150 each and you are looking at $1500 to equip your lathe to use these.

If you have have any need to hold hex or square stock, thin stock or need an internal gripping collet, you will not be able to accomplish that with the ER collets. You will need a 5C setup to do these jobs.

The ER collets add another problem when working close to the headstock on small work in that there is that clunky nut in your way, versus the smooth nose of the 5C collet chuck.

You won't see many lathes using R8 collets, or many milling machines using 5C collets for the simple reason that one is for toolholding and the other for workholding. The same applies to ER versus 5C. The each have benefits for their application not provided by the other.

When the ER system reaches the age of the 5C system, some of these problems may be sorted out, although I doubt anything can be done for the clunkiness of the retention system, until that time, the 5C system will still be the system of choice for most of us.

John Stevenson
04-09-2006, 09:59 AM
When the ER system reaches the age of the 5C system, some of these problems may be sorted out, although I doubt anything can be done for the clunkiness of the retention system, until that time, the 5C system will still be the system of choice for most of us.
Jim,
With respect collets are like religion and politics you have a hard job converting anyone from a given path ;)

If you already have 5C's then it's an obvious choice but for someone starting out it's a decision they will have to make.
In my case the lathe that uses the ER collet chuck has a spindle bore equal to the largest ER32 so going up to an ER50 isn't an option and one set of collets will go from 2mm to 20mm or 3/32" to just over 3/4" with no gaps and this same set will fit the mill.

So if you reckon on a full set of 5C's in imperial and metric and the 8 or 10 mill collets a set of ER32's works out a lot cheaper.

The lathe I have this chuck on can't take 5C's only by using a free standing 5C chuck which would add a lot on in overhang and reduce my working length.

As I say it's personal opinion and I don't expect to convert anyone, only point out the choices.

vinito
04-09-2006, 10:33 AM
One more thing...
I'm not convinced that some collets are "for" workholding and some for tool holding. That implies they were designed with a bias toward one or the other. Collets are just designed to hold stuff. The concept for any one of them is extremely basic - squeeze a flexible thing so that it will grip something. They make 'em flexible via less than a half-dozen methods. Other than that they just come in different sizes & taper angle and some work better than others for holding the aforementioned stuff.

The fact that some are used for work holding and others for tool shanks has to simply be a product of marketing and luck, and maybe a bit of habitual thinking from we, the machinists.

The only feature that might bias one toward work holding is that it be hollow to allow rods to pass through. I guess I'm so used to my lathe's spindle bore keeping me from doing that so often anyways that I don't think of it as much as one usually does. It's certainly worth considering for a lathe chuck, and if a guy end up spending a good amount of money on one it should definitely allow stock to pass through. As for collets for holding tools, the hollow tube wouldn't matter so anything goes here. I have a mill that came from the factory designed and built for many years that uses both 5C and 4C collets for holding tools:

http://home.kc.rr.com/vinchenzo/shop_files/body_files/Hard%20V.jpg (http://home.kc.rr.com/vinchenzo/shop_files/body_files/Hard%20V.jpg)

The problem with this mill is finding affordable 5C mill arbors. Marketing... Where are they Mr. S. :confused:

Glad to see the ER lathe collet chuck is actually being produced by somebody. There's quite a few cool things on that site John.

J Tiers
04-09-2006, 11:20 AM
One more thing...
I'm not convinced that some collets are "for" workholding and some for tool holding. That implies they were designed with a bias toward one or the other. Collets are just designed to hold stuff.

The longer the grip length, the better they are for holding tooling.

The ER appear to have a very long grip length, the 5C seem to have a much shorter length.

Therefore it is ENTIRELY fair to call the 5C "workholding".

A collet with a longer length may be good for toolholding, but may have troubles holding a shorter workpiece, especially if instead of a "pivoting" action, it has a radial compression action. Obviously this is no matter if you have a long piece of stock.

With 5C at $5 per in "most likely acceptable" quality, and the ER at quite a bit more, there certainly is a choice, but for many it isn't a credible choice.

That may be so even though an ER holds any diameter over a range, INCLUDING non-stock sizes. That last is a good point, however. Even at 0.015 steps, there are sizes that are not advisable to grip with a 5C.

But, the price differential is large for that capability if it is not needed. And you are somewhat forced to buy a complete set, in that you buy a size, and it covers the range, for which you pay, whether you need it or not. If you need 4 or 5 specific sizes only, the higher price becomes silly to pay.

"Better" or "best" may simply not be an option for some/many. I do not subscribe to the idea that "if you can't get the very best, you should do without altogether".

The point on hex and square has not been addressed.

I assume that ER are also commonly available with hex or square bores...... otherwise this would have been brought up before. I DO wonder what incredible price they might have.......

John Stevenson
04-09-2006, 11:50 AM
One advantage of ER32 tool holding collets that's of particular use to us Europeans, could effect the US later, is you only need 4 common ones.
Standard Imperial milling cutter shank sizes are 1/4", 3/8", 1/2" and 5/8"
Standard metric milling cutter shank sizes are 6mm, 10mm, 12, and 16mm.

Four collets 6-7mm, 9-10mm, 12-13mm and 15-16mm will hold all 8 sizes.

TECHSHOP
04-09-2006, 03:01 PM
It looks like LOML may have not gotten the "better end" of the deal when she sold my lathes and tooling; the Rockwell was 4C, collected over the years, and the little Rivett was something completely different, I don't recall what (I think it had an "A" somewhere in the "type"), collets came with the lathe.

In the place I was going to work, but was partially destroyed in a fire had some Wadkin stuff (not able to salvage anything but the cast iron), it is all being replaced with some newer Euro machines. They have saved the toolling, but it doesn't fit their other machines or its replacement. I expect the "orphan" tooling to be autioned off, or sold to someone else locally. The guy that owns/runs the place is pretty sharp, so I don't expect any "bargins".

JCHannum
04-09-2006, 03:26 PM
The point on hex and square has not been addressed.

I assume that ER are also commonly available with hex or square bores...... otherwise this would have been brought up before. I DO wonder what incredible price they might have.......

I did mention hex and square collets as well as the ability to hold thin sections. I am not aware if they are available as yet. I also did not mention pot collets, and their advantage for holding odd shaped parts for production runs,nor the availability of lever collet closers that allow part changing on the fly. These are not available to the ER series either.

There is no one single work or tool holding system that will meet all situations. Some are better than others, while some have not yet reached their full potential. The ER system may well develop further, but it has a long way to go to offer all the features already available in the 5C system.

vdisney
04-09-2006, 05:01 PM
I too am a big fan of 5C collets. After springing for the cost of a Bison Tru-Set 5C chuck, collets are cheap. Now I have round, square and hex. All american made and none over five dollars.

J Tiers
04-09-2006, 10:53 PM
I did mention hex and square collets


yep, YOU did, but the proponents of ER as the one and only that we all must use..... THEY did not touch the point ...... :p ;) :D

vinito
04-10-2006, 12:13 AM
The longer the grip length, the better they are for holding tooling.

The ER appear to have a very long grip length, the 5C seem to have a much shorter length.

Therefore it is ENTIRELY fair to call the 5C "workholding".

I figured this would come up...
The longer the grip length, the better they are for holding tooling?
I'd say the longer the grip length, the better they are for holding whatever. This varies with the length and angle of the taper as well, i.e. shallower taper = tighter grip, everything else being equal. Of course this is also true when trying to release collets as well and a, say, Morse taper (drawbar type) takes more than you might like to remove it every 10 minutes. In walks compromise. The wealth of collet varieties is evidence of engineers believing their idea is better (whether for function or proprietorship), which just might be true for the application in front of him/her.

I'm not trying to be contrary. You are probably referring to the usual need to grip hard, polished tool shanks so they don't slip as opposed to the usual need to grip softer, rougher bar stock. In these cases it's true that an R8 or ER collet performs better than 5C, etc. Of course, you don't notice the difference until you pass the limits of the envelope, and they all have a limit. On my mill which was designed specifically to use 4C & 5C collets, you just have to learn it's limits and work accordingly. I haven't scored a collet yet (...in that mill), but I won't say it'll never happen.

I think we are all in agreement that no collet is a one-size-fits-all, or the best. Hopefully Schutzund and others are getting ideas & helpful info from all this. If nothing else, having to explain myself is reinforcing my beliefs on the issue :D
Never thunk I'd see myself debating collets ;)

vinito
04-10-2006, 12:21 AM
one more thing...
Just an example I remembered regarding engineers' better ideas.

I have a Titan tool holder that has a really short, hard taper. The collet grips so badly it's only good for centering the tool shank. It has a keyed thing inside to do the driving that has an I.D. thread to accept threaded end mills. I guess you can still get 'em, but what a PITA, and expensive. In my opinion it's a pretty screwy idea, but some group of guys thought it was a good solution for something.

OK, now I'm rambling.

John Stevenson
04-10-2006, 04:23 AM
yep, YOU did, but the proponents of ER as the one and only that we all must use..... THEY did not touch the point ...... :p ;) :D

First off I'm not saying ER's are the one and only, I'm just pointing out the advantages and leaving people to make their mind up.

As I have frequently said for anyone with a rake of 5C's it better to go this way.
For anyone just starting just be aware of the choice.

You can get square and hex in ER32's and 40's, not seen them in other sizes but not looked. They are expensive at the moment but this is all altering, I used to pay 10 UKP per collet at one time now they are down to 5UKP.
Because of the large gripping range or ER you can get away holding square and hex in ordinary round collets by the corners for the odd jobs.
I do one job where I have to make double threaded studs but with the hex in the middle. I hold the hex in the collet, turn down one end, thread, spin round and hold on the bit I've just threaded to do the other end all with the same collet.

I have another collet here that's been wire eroded to leave a keyhole shape to take a piece of extruded brass strip do the round bit of the keyhole shape can be turned to make a bearing surface so anything is possible.

Vinito,
Those threaded mills are called Clarkson's and were very popular here. Their main advantage is that the cutter can't walk out the chuck. The more force is put on the cutter the more it tightens itself up in the chuck

J Tiers
04-10-2006, 10:16 AM
Workholding vs toolholding? Grip length?

Just PURELY a matter of leverage...... Longer grip length means the TOOL or WORK is held more securely.

But, since WORK is often of different sizes, it is a compromise, and it makes sense to have workholding not REQUIRE a long gripped length, because it might not be available on the piece, for second operations, at least. No matter if you are gripping a 10' stick of stock.

A collet that REQUIRES a long grip can be disadvantgeous for workholding, therefore, but is probably superior for toolholding, if there will be any sort of side-load on it. Less walking out of the collet, less deflection.

As far as gripping hex or square by the points, I figured that would be mentioned. You DO risk rounding or smashing them, which is something that can't happen if the collet fits the shape.

And, sure, EDM can fix that. But the collets aren't commonly (if at all) available with the common stock shapes, possibly because they are intended for tools and not work stock holding.

JCHannum
04-10-2006, 11:11 AM
Jim,
With respect collets are like religion and politics you have a hard job converting anyone from a given path ;)

The situation is more political then religious. It is a little known fact that Algore invented collets, and Clinton was actively involved in research on several different methods of toolholding.

When the question of workholding was put to Kerry, he responded with "I have a plan for that. Mr. Bush is using the wrong collet in the wrong place at the wrong time."

So like anything else, the reason we do not have a single all encompassing collet sysem is Bush's fault.

Orrin
04-10-2006, 03:38 PM
I'm lucky enough to have large enough spindles on my lathes to accept a 5C adapter. What I like about having 5C collets is the ready availability of 5C spin indexes. I can take a piece out of the lathe, collet and all, and put it into the spin index; and, vice versa.

Regards,

Orrin

John Stevenson
04-10-2006, 04:18 PM
Then you need one of these ;) :D

http://homepage.ntlworld.com/stevenson.engineers/lsteve/hidden/ER%20spin%20indexer.jpg

Spin indexer that takes 5C and ER32 collets so you take your choice.

Schutzhund
04-16-2006, 07:38 PM
Adding this link for those who may stumble on this thread in the future.

Claw made an R8 collet chuck for his Grizzly G9972Z which has an MT4 spindle.

http://www.homeshopmachinist.net/bbs/showthread.php?t=18928

jdunmyer
04-16-2006, 09:25 PM
Before I got my BridgePort, I happened to see a collet set 'On Sale' from one of the suppliers. Knowing that I'd need collets, I ordered the outfit, consisting of an R8 shank/holder (uses a closer nut) and a set of collets that turned out to be RDO-35, according to the cox-internet.com site that someone so kindly provided. I was thinking of chopping off the R8 shank and attaching a 'backplate' so I could use the collets on the H.F. 7X10 lathe. The configuration would be like that ER lathe collet adaptor shown in this thread.

The basic plan would be to final-machine the backplate after attachment by spinning the assembly on a piece gripped in a collet and mounted between centers.

Any thoughts?

Spin Doctor
04-17-2006, 07:59 PM
The big problem with ER series collets for lathe work as I see it is the fact that all of the collet set-ups I have seen close from the front. This automatically precludes the ER from being as adaptable as the 5C series is in all of its versions. Of course one fault of the 5C is that as a draw in collet differing ODs will result in inconsistent work lengths when using a collet mounted stop unless using dead length collets (pricey). What I would prefer to see on the commercial adaptors for 5C collets that are out there is the use of Hardinge's 4 degree spindle nose so as to allow the use of the 5C's whole bag of tricks. Haven't we been here before??????????????????????????????????????