Collets this and that.

[P B G]

First post here, but looking for guidance on what direction to go before I start spending the $$$.

I have a number of tools that lack collet assortments, my mill is a Gorton Taper - and I have a full set of their proprietary, but would like to make a Gorton to ER or similar adapter or simply mount a 1/2" straight shank ER into the collet when in use.

But I also have a few Lathes that I would like to begin using collets on. One is an Atlas/Craftman 109 - MT spindle with threaded nose. Also have a SB Model A which is ~the same thread on the hose and the same taper.

I'm debating making ER threaded adapter for the nose, also because I could get the same ER collet set to work with the shank on the mill, make an adapter concentric on both lathes.

Negative of this - is of course the reverse direction on the lathe can loosen the chuck. The positive is that there's some through capacity with no drawbar.

I could also buy MT 2 or MT 3 collets w/ a drawbar for the lathe. I could do an MT - ER collet with a drawbar.

I could buy and obtain 5C collet chuck.

Little machine shop the 3C nose adapter and collets (drawbar).

So I guess my main question to the masses here - knowing the size and capacity of these machines - which direction would you go? Also ER sizes - I think it would be nice to go larger on the Lathes to have capacity above the spindle bore for parts, but that may be somewhat obnoxious on the mill.
The 3C is lathe specific and probably more $$$ than it should be, 5C of course makes sense if I buy a larger/newer lathe.

So before I go nuts - what would you guys do?

 

[seanb]

Er 32 or er 40

Better flexibility for under and over size

Check out arc trade euro

In England they have some cool fixtures that take er

 

[Bob Korves]

MT and some other collet systems (like R8) do not allow work through the collet because of the solid drawbar in the middle. On a mill, no problem, but on a lathe it can be quite limiting to not be able to put longer work or stock through the collets and headstock. Collets like 5C use tubular drawbars that work and stock can protrude through.

 

[brino]

Hi @P B G,

First, Welcome to the group!

Next, Great question! It can be more than a little intimidating when you see the number of collet systems available.

Like you, I have different tapers in both the lathe and mill; my lathe has an MT-2 tailstock taper. My mill has a B&S #11 taper in both the horizontal and vertical spindles. Honestly, I'm not sure what my lathe headstock taper is(1937 Southbend 9A model 409B)....I thought it was MT-3, but I believe I read here that it's Southbend 3C which is very close to MT3 (except for the length, maybe?).

For both my old and new lathe I bought ER-32 collet chucks from Beall USA:
http://www.bealltool.com/products/turning/colletchuck.php

I wrote about them here:
http://www.hobby-machinist.com/threads/is-there-a-definitive-article-on-collets.36227/

I didn't like the MT3 for the lathe, since they are so small the draw bar was solid which mean you cannot put stock thru them, and that limits the length of what you can hold. With the Beall ER-32 chuck I can fit up to 3/4" stock right thru the headstock!

You do NOT have to buy one, several folks here have built their own, just buying the nut. If interested search the site for them, if you cannot find them send me a private message and I'll try to dig them up. (The nut is a little complex as it has an off-centre lip to push/pull the collets in the taper.)

For my mill, I always use the B&S#11 to MT-4 adaptor, and then use MT-4 collets in that with a solid draw-bar (all-thread).

-brino

 

[P B G]

Thanks so far guys.

The 3C is a small 5C so you can use a tubular draw bar, but they are more money and need an adapter, little machine shop has them but the cost is more or collet than 5C and the blocks etc aren't very available. MT3 I believe is the spindle taper on both.

Sounds like ER-32 is a popular size for these tools - I like that due to having the ability to use it for end mills and drill bits on the mill and then on the lathe for pass through.

Both my lathes are quite small through bore - the real reason I don't like the DIY spindle adapter er-32 is the threaded spindle and reversing - but then again 3c has a really small bore in the drawbar.

I also have a horizontal mill I thought was 5C but isn't... If it was it'd be 5C all the way but it might be a b&s.

It's a project so once I get the spindle bearing sorted I'll decided if it's worth figuring the taper.

 

[P B G]

MT and some other collet systems (like R8) do not allow work through the collet because of the solid drawbar in the middle. On a mill, no problem, but on a lathe it can be quite limiting to not be able to put longer work or stock through the collets and headstock. Collets like 5C use tubular drawbars that work and stock can protrude through.

So the mill I have has these three flat tapered spring collets - a proprietary thing, the largest available is 1/2" capacity.
My plan for that machine is an ER collet chuck, I'll probably end up with two, something like an ER 20 and an ER 32 or 40 (whichever ends up on the lathe)

The Tormach Tool system is a 3/4" R8 or MT collet - I can't do that capacity, so I want to do something similar by turning some steel rings which will have a clearance for the nose of the gorton collet, and then a ring to fit to the nose of the spindle - TTS sells a conversion ring which is epoxied onto 3/4" shanks - similar idea here but epoxy to the back of ER collet chuck on 1/2" shank.

Once I have that done I'll probably also turn a 1/2" to JT for a drill chuck.

For what MT3 to ER 32 collet chucks run on ebay maybe I should start there, get ER collets and then worry about turning my own spindle thread mounted ER chuck.