Re: How to you make a 1/8" collet on a 1/4" shaft

I think the simple answer is to put the whole collet thing on the end
of your spindle.

drill and ream for the 1/8 shaft
thread the OD for some fine thread
put a taper on the end of the shaft of 45 degrees or so.

Make a nut with the same thread and also put a matching taper in the
nut.

slit the shaft well into the threads.

when you put the nut on, your nut will compress the taper locking in
your engraver bit.


another idea is to take a 1/2 dia block and ream it to be a press fit
on the shaft and make a collet end much like a router. these can be
pretty simple to do, but you need access to a lathe.

I made a few collets for my trim router and they came out pretty
nice. the drills did not spin in any material (yet) so I'm happy
with the do-it yourself collets.

Dave









--- In CAD_CAM_EDM_DRO@yahoogroups.com, "deansala" <adsala@p...>
wrote:

> Hi everyone,
> I have not used this list in a while but when I did, I always got
> great answers. I have a situation. My mill needs a faster motor.

So

> I rigged up a Dewalt Laminate trimmer motor to the top of my
> drawbar. I connected a 1/4 in shaft to the motor which runs down

the

> drawbar hole(about 16" long). On the lower end (turret end) I
> installed a part that houses two high speed bearings in which the
> shaft runs through. Now sticking out the very bottom of the piece

is

> a 1/4" high speed shaft about 1-1/2" long which needs colleting.
>
> The whole idea is so that I can CNC engrave using high speed

engraver

> bits. I need to some how attach an 1/8" engraver bit to the 1/4"
> shaft. What I need (I think) is piece that has a 1/4 female collet
> on one end and an 1/8 female collet on the other. It can not be

more

> that a couple of inches long. I have tried boring 1/4" and 1/8"
> holes in some round stock and use set screws to attach to the shaft
> and mount engraver bit. I works ok but it's very hard to get it

all

> true at 30,000 rpms!
>
> Any thoughts or better yet can someone make me the part I seek?
> Dean