Small Collets, Snrink Fit, Etc

I'm looking for a tiny threaded collet. ER collets are fine, but you can't really use them to make long reach tooling. Shrink fit is an option I guess. My goal is to make my own mold making tool holders to use modest price proper geometry end mills in long reach applications to have greater rigidity than a long reach mill and better cost effectiveness than a tapered end mill to achieve that. I know. I know. It already exists in some types of tool holders,but I want to make something a little more universal to fit into tool holders I already have. Harvey tools makes an end mill extension, but their current version isn't tapered or designed quite right for what I want. I could buy them and maybe modify them, but they aren't cheap. Mostly I am just thinking out loud right now. I recently picked up a surface grinder, and I am making plans for making a cylinder grinding attachment for it. It would be ideal for finishing hardened tool holders like this.

Might actually use some of my grinder vises like they were intended. LOL. =======================================================

If you make extensions with integral collets by slitting them crosswise, the closer nut could have tapered pipe threads.

On 4/14/2020 5:49 PM, Jim Wilkins wrote: > "Bob La Londe" wrote in message news:r74v76$p01$ snipped-for-privacy@gioia.aioe.org... >

The idea is to have maximal support for smaller mills when deep machining. I would prefer in internal draw bar to an external closer nut I think. I did a search for "straight shank end mill extension" just a few minutes ago and found quite a number. Most use set screws. One that came up in image search showed a collet, but when I went to their website it they just showed a set screw type.

These would only be useful for pockets with a lot of draft angle or a feature of the floor of a pocket, but I just finished an open casting mold with pretty deep pockets and tool deflection affected finish quality with a lot of tool stick out. I had to slow the job down a lot.

On the other screen I am working on a rough model. With a 3/8 Ball mill for the angle I needed with clearance I could have just one inch of stick out and be upto to 5/8 shank. Of course I could just continue the taper as far back as I want to fit into the largest tool holders I have.

Once I have it dialed in to make them I could make ones with a little more slender profile for tiny mills and less available angle clearance too. Of course its all a trade off.

I recently engraved the bottom of some deep pockets with a company logo using a 1/16 ball nose end mill. A tool extension sized for this application would have allowed me to feed much faster than I had to run with the ER collet tool holder and the long reach end mill I had to use to do the job.

They will not be a magic cure all, but they would speed up many jobs and improve surface finish doing it.

On 4/14/2020 5:49 PM, Jim Wilkins wrote: .....

The idea is to have maximal support for smaller mills when deep machining. I would prefer in internal draw bar to an external closer nut I think. ==========================

single 1/4" or 5/16" collet costs $18.

#2 collets go up to 1/2", and you can buy a reamer for the female socket.

drilled one for a drawbar to make a sliding and rotating end mill grinding fixture.