The 5C back
5C collets are a very popular size in the machine shop. Sometimes, however, you may not have the right size collet or you may need to hold a part that can only be held in a 4-jaw chuck. This chuck with a 5C back makes it possible to quickly change from a collet to a chuck without breaking down your setup or changing to a different machine. Simply remove the collet and insert this chuck into your 5C holder. When done, change back to collets just as easily. This back has the standard 5C taper, thread, and keyway. Because it is CNC machined from a single billet of steel, the back and body are concentric.
The compact 3.1″ four-jaw chuck can be fitted quickly in a 5C collet holder to do a job requiring the versatility of a chuck. Included is a P/N 3020 Sherline 5/32″ T-handled hex driver to adjust the reversible jaws.
NOTE: The 5C is a larger collet size that is used on full-size machines. This chuck was designed to work on full-size machines like we have in our shop. It was not designed to work with our Sherline lathes.
3.1″ Diameter 4-Jaw Independent Chuck
While collets are very accurate, each collet has a very small clamping range. You may not always have the size collet you need for a job. A four-jaw chuck can also be used to hold irregularly shaped parts. With the use of a dial indicator, parts can be centered with a great deal of accuracy. Four-jaw chucks can also be used to deliberately hold a part off-center.
The stepped jaws can be used to clamp either externally or internally, and the jaws are reversible. The 3.1″ (79 mm) 4-jaw chuck is designed to grip from 3/32″ (2 mm) up to 1.5″ (38 mm) diameter stock with the jaws in the normal position. For larger diameters, the jaws must be reversed and can grip up to 2.75″ (70 mm). The chuck has a .79″ (20 mm) through-hole.