In this video I build a set of large button lathe jaws. The design is quite popular and accessible, of which there are a few variations. I begin by marking the holes from the chuck by drawing through an individual jaw, and using a compass to draw two circles from the centre, marking where I will drill. I roughly cut the circle from MDF board, although birch play would be more durable.
The pillar drills throat was too shallow to fit the disc, so I have to do this by hand. I also countersink these holes and check that the original machine screws can fit through them. I screw the chuck onto the lathe, and true the circle to its turning axis. Turning MDF is very messy. I mark some increments, and lathe shallow indentations where I will screw the rubber feet onto the jaws.
I mark the corresponding segments of the jaws to those of the chuck, and cut the pieces out into quarters on the table saw. Each segment is screwed onto the individual jaws of the opened chuck. This really reminds me of the dinosaur in Jurassic Park that eat the fat hacker.
I place the chuck onto the lathe, and attach something to it, to test whether it holds and is centred.