What to do with some R8 collets?

[JSnover]

I have a set, rescued from an old Bridgeport that went down the road years ago. One of these days I was going to get a set of collet blocks or a spindexer, like we had in the shop for our 5C collets but they just don't make such a thing. As far as I know they don't make an adapter either, and I no longer have the equipment to make my own.
I understand that: reduced functionality and work-holding capability just makes it a no-go but it might have been handy for an occasional small job.
Is there any practical use for R8 collets without a machine to mount them in, or would I be better off just finding a new home for them?

[country gent]

Other than the extra range of the 5C collets making your own blocks or spindexer the only different is what collet you machined them for. On some smaller machines the R8s may be a benefit allowing for smaller tooling.

If there is a chance you might acquire a machine that uses them in the future that uses them I would wrap them in oil paper and store them.

I have a set up for sharpening end mills that uses bushings and 2 spindles, I have thought about boring the one spindle out for either an r8 or er 32 collets. It would save the spindle changes and make set up easier.

[John Taylor]

Problem with using an R8 in a spin jig is that you can't run long pieces. Most of the spin jigs I have seen and used use the C5 collets.

[Green Frog]

I have only limited experience with machining and even less with R8 collets... that only with other people's Bridgeport mills. If I had a set with no prospect of getting a Bridgeport or other similar sized mill, I think I would just sell or trade them for something I could use.

If you have the proper sized lathe, you might be able to turn up a collet sleeve to adapt them to it, but as has been stated, their lack of full bore (all the way through) limits their usefulness there to the occasional screw holding/making task which a 3 or 4 jaw chuck does about as well. Likewise, Collet Blocks or a Spindexer without a mill are of pretty limited usefulness.

Froggie

[405grain]

There's a reason that spindexer's use 5C collets and not R8. An R8 collet has female threads on it's stem, and is pulled into it's seat by the male threads on a draw bar. This means that pieces of longer stock cannot pass all the way through an R8 collet. The R8 collets were designed to be tool holders, not stock holders. A 5C collet has both male and female threads in it's stem. The 5C collet is pulled back into it's seat by the threads on the outside of the collet body and pieces of stock can pass through the collet. The internal threads in the 5C collet are so that you can install a collet stop and do production work on pre-cut pieces of stock. A 5C collet was designed as a stock holder, not a tool holder.
Without a milling machine to use them in your better off selling the R8 collets and then using the proceeds to purchase something useful. Or, keep the collets and buy a milling machine to go with them. (Doing that might sound impractical, maybe even condescending, But I have been stoopid enough to build a rifle just because I have a set of molds in that caliber, so "been there, done that")

[JSnover]

Yeah, I knew all of that, I was just wondering what options might be out there.
Since a mill probably will not appear in my garage I think I'll just clean these up and pass them along.
Thanks.