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Dunc
04-28-2009, 10:23 PM
I bought several (look like LMS #1948) at a used tool sale.

Most collets I have seen in my very limited hsm experience have a nose cap or closer. These do not. They are threaded for a 3/8-16 drawbar.

Does the nose cap contribute to the force holding the end-mill/work in position? Or, is it intended only to facilitate loosening the collet's grip?

Are these suited for a small lathe (headstock is MT3) to hold work and in a minimill (same MT3 spindle) to hold end mills? Is the drawbar - without a nose cap - adequate to hold the work or cutter against machining forces?

I see no reference to a closer in the LMS catalog. Is this the intended use?

Any other tips/thoughts/cautions welcomed.

EDIT: Oops! My apology to the moderator and members.
I managed to post this one twice. Thanks to everyone who responded (to both threads).

danlb
04-28-2009, 11:28 PM
The mt3 collets are slit along most of the length and hold tools quite securely. The draw-bar pulls it into the bore, causing it to grip uniformly.

They work well in both mill and lathe. They are highly concentric.

They should be used with shanks of the same size as the collet. A 3/4 inch drill will work perfectly in a 3/4 inch collet, but a 23/32 might not.

Dan

Astronowanabe
04-29-2009, 12:29 AM
I bought several (look like LMS #1948) at a used tool sale.

Most collets I have seen in my very limited hsm experience have a nose cap or closer. These do not. They are threaded for a 3/8-16 drawbar.

Does the nose cap contribute to the force holding the end-mill/work in position? Or, is it intended only to facilitate loosening the collet's grip?

Are these suited for a small lathe (headstock is MT3) to hold work and in a minimill (same MT3 spindle) to hold end mills? Is the drawbar - without a nose cap - adequate to hold the work or cutter against machining forces?

I see no reference to a closer in the LMS catalog. Is this the intended use?

Any other tips/thoughts/cautions welcomed.


collets with a draw bar limit the length the piece they are holding can be
inside the collet.
so in a sense they are (at least) tool holding collets since something like the shank of an end mill is pretty short. the "nose cap" on other collet types does the same job as the drawbar without getting in the way so you can feed longer stock through the collet.

These collets (I just got a set as well) can be used for holding short work and tools but may not be what you would use for machining parts off of long stock in a production environment.

Andrew_D
04-29-2009, 08:30 AM
I have a set of the LMS MT3 collets to use in my mini-lathe and mini-mill, both with MT3 spindles. They work quite well, but you may hear that an ER-style collet is better for tool-holding since it is slit from both ends and therefore clamps better to the tool. I've used both. I tend to use the ER-style unless I need more headroom in the mill, then I switch to the MT3 collets.

Remember that with a drawbar, you can't pass long stock back through the headstock of the lathe.

Andrew

ptjw7uk
04-29-2009, 02:04 PM
Some draw bars are tubes so small diameters can pass down the centre.
The myford morse collets are front working so rod can also pass through them although of small diameter.

Peter

Teenage_Machinist
04-29-2009, 09:34 PM
Meant for holding tools, really. Not so much work. mainly for the MT3 Mini Mill.

3C are more common for work holding, I think.