A variation of the dead length collet is the Crawford Multibore collet. This sys- tem has collets made of segments held together by springs. The collets are of vari- able diameter and have quite a large closure range. They are more likely to be found on a larger commercial lathe, although you can get collets for smaller machines.
 
Watchmaker’s collets can be used in most lathes by making an adaptor for the headstock and a drawbar (or tube). Watchmaker’s collets are very accurate and can go down to very small sizes, but they have limited use in most workshops. You can get a special watchmaker’s spindle for the Emco Unimat lathe and there is also a version of the Cowells lathe, the CW90, that takes watchmaker’s collets. For most of the work carried out on the lathe, you will find that an ER holder that
mounts onto a chuck backplate is most useful.