3/4-16 thread for mounting 3 or 4 jaw chucks
The Chuck Adapter can be a very useful accessory for both the Lathe and the Mill. The chuck adapter can be used to hold the 3-jaw chuck on the milling attachment. This allows the lathe spindle to hold the cutting tool rather than the workpiece. The Adapter can also be used on the Micro Mill. It can hold the 3 or 4 jaw chuck on the table and allow the user to hold round stock very easily, rather than trying to hold the material in a vise. As you can see it can come in handy for special applications.