I use the tapped wood method as well - it's the easiest and cheapest way of making custom jigs. especially when it comes to vacuum chucking. The first 4 chucks I made myself paid for the whole vacuum pump aand connections!
I have found boxwood to be the most reliable in terms of weather interference (i.e. movement), with maple useful if nothing else is available. I use an oval shaped log of solid boxwood and cut the thread into the end grain. That way I also have a naturally shaped handle that I can use to remove the chuck from the spindle, if necessary with the use of a boa.
So long as you true up the end of the log before starting to drill (so it sits true against the spindle stop), are reasonably accurate when you drill the hole, and use the tailstock for support when you are tapping the thread, it works! The benefit is that you screw the chuck 'base' onto your spindle and then true things up.
I mostly use boxwood as the 'nut' part, and then epoxy onto that whatever 'faceplate' part I want to make. The advantage of doing this is that even eccentric chucks can be made easily - about 40 minutes from start to finish, including coating the whole of the exterior with thin epoxy resin to make it air-tight when I want to use them with my vac chuck system. 24 hours later, you have a long-lasting chuck that cost next to nothing and is made to suit the job in hand.
