Help ID this collet set

[kilohertz]

Last year my friend downsized his shop and sold me a mess of his tooling and such, and then moved away, and in there was this little box of collets which I am having a hard time figuring out how to use, or what they would be used for. Keep in mind I am a complete newbie so go easy on me. I know the plunger is for knocking out the collet out of the holder but what holds the collets in the holder (no internal threads) and no threads on the outside holder. What is the threaded ring for, it has internal threads, about 1.25" dia.

Any help would be greatly appreciated.

Thanks!

 

[benmychree]

I think that the threaded nut fits into the recess of the collet when the collets are compressed inwards, and the nut both tightens the collet into a tapered bore and also ejects it; the threaded nut undoubtedly screws onto a machine spindle. I wonder if the knurled part is used to collapse the collets to fit them into the nut.

 

[kilohertz]

Mmm, yes, I think you nailed it, makes perfect sense now that you have explained it. Now I need to figure out what spindle thread it is, and what the taper is, MT2, 3 etc.

I have both a Hercus 260 and Cincinnati Hydro shift.

Thank you!

 

[markba633csi]

I see Hs on them I wonder if that means Hardinge?