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

Hi Dean,
why go with a collet? I had the same problem last year and decided why not
shrink fit the 1/8" engraver bit into a slightly undersized bored and reamed
hole in the end of the 1/4" shaft. You need a precise hole that has very
smooth walls maybe .001 less diameter that the bit shank. Heat the end of the
shaft and the hole will grow enough to slide the bit in, then remove the heat
and the shaft will shrink down tight on to the shank. It's perfectly balanced
for high speed operation. I think the commercial version uses inductive
heating, like a bearing heater.
I tried the Dremel stuff but found quality lacking. First was the jacobs
chuck version, terrible vibration. The collet nut version reduced most of the
vibration and I got higher speed but the collet and nut that I bought was end
faced on a slant. Maybe it can trued up by holding it against a mini grinder
while it's running, but you'd expect better out of the box.
Cheers,
Denis

On Wednesday 30 July 2003 11:28, you 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
>
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
>
> Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...,
> timg@... Moderator: pentam@... indigo_red@...
> [Moderators]
> URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:
> aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
> you have trouble. http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
> sister site to the CCED group, as many of the same members are there, for
> OT subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
> DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........ bill
> List Mom
> List Owner
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/