There are several ways to attach threaded metal fasteners into wood fixtures. For example, inserts and t-nuts can be used to add a threaded connection to a jig. But often I prefer to drill and tap threads directly into the wood fixture. Many hardwoods can be drilled and tapped, however softwoods lack the necessary machinability and holding capacity. The best wood I have used for threading is Jatoba, (Brazilian Cherry). Jatoba is very dense, hard, fine grained, and threads extremely well. Oak and Padauk are fine also. I find these threaded wood fixtures hold a bolt extremely well.
Hardwood is a forgiving material to drill and tap. Use a 5/16” drill bit for 3/8” threads, 7/32” bit for 1/4 “. I don’t thread anything less than 1/2” thickness. Use a standard coarse tap to cut the screw threads.
Making threaded woodworking jigs, clamps, furniture handles and knobs from exotic hardwoods adds a beautiful touch to projects. Material is not cheap, but these parts are small so final cost is low.