Vintage Lathe Collet Identification - Help Needed

I've got a set of vintage lathe collets that I recently purchased from an elderly gentleman who said that they belonged to his grandfather. They're old. Really old. They don't have any identification markings on them other than the size stamped into the top of the heads. The largest is stamped 135, and this appears to stand for 13.5 mm. They measure approximately 0.629" in outside diameter at the shank, and about 0.867" in diameter at the head. The overall length is about 4.425". The thread pitch looks like it is 20 threads per inch. When I attempted to match it to a metric thread the closest that I could find was 1.25 threads/mm, but I could tell that it was off slightly. The outside diameter of the threaded end is very close to 9/16", and the diameter at the thread root is 0.540". I'd like to find out who manufactured these collets, and ultimately what lathes they would have been used on. Can anyone provide any insight. I've looked at a lot of collet dimensions for American lathes and can't seem to find any that match these dimensions. Could these be European? I know that 0.629" is pretty close to 16 mm. Any insight?

Maui

Nothing in the 1918 Hardinge catalog with a .629" body. The long skinny shape is probably early, wherever it was made. Larry

I thought that they might be 16 mm Lorch collets - they certainly have that long skinny look. But I don't know what thread the 16 mm Lorch collets used. Does anybody here know?

they look like lorch collets to me. but Im not 100% sure on threads either.

After an extended search it appears that these collets were used on the earliest Deckel/ Alexander SO grinders. This is an excerpt taken from Tony's website,


SO and SOE
Intended original to compliment the Deckel range of pantograph engravers and die sinkers, the long-lived SO is known as a "single-lip type" and, due to its success, has been widely cloned with many examples (of varying quality) now made in China. In the UK the best-known copy was by Alexander, who produced a version to the same very high standard of the original (as well as a simplified version intended mainly for sharpening the D-bit cutters of the firm's well-known engraving machines).
Able to mount a grinding wheel 4" in diameter by 2" wide with a 25/32" bore, the Deckel/Alexander SO was fitted with a 3-phase, 0.25 hp, 2800 rpm motor with the wheel running at around 5000 r.p.m. The cutter to be sharpened was secured in, on early models, an unknown type of collet with a 16 mm shank that had a maximum capacity of 1/2" (12 mm).

http://www.lathes.co.uk/deckel/page3.html

Maui

On my (suspected) 16mm lorch collets I measure 1.25 european pitch and 14.5mm diam on the threads. Deckel made nearly identical but with a 16mm diam on the threads. I don’t know the pitch of those. My collets are stamped with an F. The ones in this post arent. Therefore I think this person has found 16mm deckel collets.