What is a pin chuck?
A pin chuck is a tool used to hold very small diameter drill bits or similar materials that cannot be held by a normal drill chuck.
Normal drill chucks hold bits that have a shank diameter of between 10 - 13mm (⅜" - ½"), whereas pin chucks can hold bits ranging from 0mm - 2.5mm (0" - ⅛") in diameter.
Different-sized collets are inserted into the pin chuck, and vary in diameter to hold small drill bits.
What is a collet?
A collet is a circular device with jaws that forms a collar around an object. The collet is then tightened to hold the bit securely in place.
A collet is needed in a pin chuck to allow it to hold a number of different-sized tool bits.
Also, the collet encompasses the whole bit giving a more secure and stable bit compared with a 3-jaw drill chuck which only grips at 3 points.
Woodworking pin chucks
There are two products currently on the market called pin chucks. It is important not to get the two confused.
The other type of pin chuck is mainly used in woodworking. This chuck is a steel rod with a flat cut-out. A pin is placed on this flat and the whole assembly is inserted into a pre-drilled hole in the workpiece, twisted and locked into place.
The end of the pin chuck is then held in a collet or drill-type chuck to hold the piece of wood in a wood-turning lathe.