Editing Collet (section)

==== Watchmaker  collets ====
[[Watchmaking]] at [[Waltham, Massachusetts]] led to the invention of collets. Watchmakers' lathes all take collets which are sized by their external thread. The most popular size is 8&nbsp;mm which came in several variations but all 8&nbsp;mm collets are interchangeable. Lorch, a German Lathe maker, started with 6&nbsp;mm collets and the first Boleys used a 6.5&nbsp;mm collet. 6&nbsp;mm collets will fit into a 6.5&nbsp;mm lathe but it is a poor practice. Another popular size is the 10&nbsp;mm collet used by Clement and Levin. For work holding, collets are sized in 0.1&nbsp;mm increments with the number on the face being the diameter in tenths of a millimetre. Thus a 5 is a 0.5&nbsp;mm collet.

Watchmaker collets come in additional configurations. There are step collets which step inward to hold gear wheels by the outer perimeter. These typically were made in sets of five to accommodate a range of different size gear wheels. These, like straight rod-holding collets, close on the outer taper. Ring collets also come in sets of five and hold work from inside a hole. They open as they are tightened by an outside taper against the outer taper of the lathe headstock.

Watch collets also include taper adapters and wax or cement chucks. These collets take an insert, usually brass, to which small parts are cemented, usually with shellac.

The book ''The Modern Watchmaker's Lathe and How to Use it''<ref>''The Modern Watchmaker's Lathe and How to use it'' by Archie Perkins. {{ISBN|0-918845-23-8}}</ref> contains tables of makers and sizes; note that it refers to basic collets as ''split wire chucks''.