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

Dave,

Ok colleting the shaft end is a pretty good idea but...and I have
thought of this..how in the heck can I guarantee that I can ream an
1/8" hole perfectly centered in a 1/4" shaft. I have have a pretty
rigid lathe and have center drills, of course, but I have found that
sometimes my holes can get off center. At 30,000 rpms, this might
produce vibes. Maybe you can suggest a lathe technique that will
guarantee centerness of my hole. I guess I can use the same idea when
threading the shaft as well. Probably not as critical but may lower
vibrations.

Thanks
Dean



--- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude"
<davemucha@j...> wrote:

> 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