Re: Unkown collet type, where does it fit on?
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I have eight or ten similar collets to those in “Silverrs” photo. Mine came from the E. Howard Clock factory, in Waltham, MA at that time. When I worked there in the early fifties they were still used in the repair department to hold and bore one off gear blanks or finished gears being mounted to clock arbors. I do not remember the shank diameters of mine, but I know they have a 1/2” diameter 24 tpi thread for the draw bar. Mine are comparable to the 3C collets I use in my 9” South Bend.
The collets I have were of three metals. The smaller ones are from steel, a couple are brass, and I guess were special order from the tool room, and the largest appear to be made from cast iron. Most of the ones in the picture close against the taper in the throat of the spindle collet adapter as would an ordinary wire collet. The larger ones that have a taper going out to the rim use a special adapter with a corresponding taper screwed to the nose of the lathe spindle.
Nelson is right in his observation that they are “Watchmaker’s” collets. In that trade they are called “Wheel chucks.” I have a set for my 8 MM watch lathe, and I know they were also made for 10 MM lathes: I have a friend who lets me borrow his set when I need them.
They look like watch makers collets.
On Sunday, September 24, 2017, 1:48:15 PM EDT, silverrs@... [SOUTHBENDLATHE] <SOUTHBENDLATHE@...> wrote:
I found 24 collets. Th mesurements are 20.8mm 25G/inch thread.