Help Identifying these collets

[rls1160]

Hi everyone,
Included in a bunch of tooling I received when purchasing a tool makers shop equipment is a box of collets that are Marked D-S and D5. I am posting pics of each.

Both collets look to have 13/16" internal threads.
The machined base on both collets measure 1.262" of an inch in diameter.

The outside diameter of the tapered split ends of both collets measure approximately 1.693"

The D-S collet length is 3.055"
The D5 collet length is 3.062"
So basically the same length.

I have a Logan 12" model 2557V screw lathe that uses 5C collets.

I have a Series 1 Bridgeport mill that has R8 collets.

What machine would use either one of these collets?

 

[L Vanice]

One collet is marked D-S and the other is marked DS, so they fit the same device and were likely made by different companies. Is there an internal thread?

Larry

 

[boslab]

Looks like the collet set I got with my Harrison lathe, the draw tube is internally threaded and the nose has a peg to stop them spinning, oddly I never use the thing as the collets are imperial, bar stock is metric and I’m lazy!, besides I like messing with a four jaw, you get quite quick at it,
Mark

 

[rls1160]

One collet is marked D-S and the other is marked DS, so they fit the same device and were likely made by different companies. Is there an internal thread?

Larry

Yes Larry the collets have internal threads that look to be 13/16" i have not checked thread pitch.

 

[rls1160]

Internal threads

 

[L Vanice]

Draw-in collets with internal threads, like the common Bridgeport R8, are usually restricted to milling machines and are meant to hold end mills and other mill tooling. The reason is that lathe collets are more useful if they can hold a long piece of stock, so threaded lathe collets have external threads to allow long stock to fit inside a tubular draw bar.

Another possibility is a cutter grinder or grinding fixture. The .323 inch collet will hold a 7/16 tap shank. The .968 inch collet is not a tap shank size or an even number of millimeters.

Larry