Chin rest Drill size?
What is the drill size for chin rest mount?
And do i drill it in a angle?
Depends on the screw diameter.
There's no standardization for those parts. Screw diameter, thread pitch, spacing between the legs, varies. The best way to proceed is to drill test holes in some scrap wood of similar hardness to your chinrest, then screw the parts in to see how it goes. You don't want it too loose of course, but you don't want it too tight either, so you don't split the wood.
@mark so would i have to drill it in a angle?
I'd say no. You want the holes perpendicular to the surface your drilling into. But you have the parts in hand, and should be able to judge that better than I can.
I agree with Mark. Take a scrap of hardwood (ash or maple) and test it out first.
Ideally you should determine which thread is on the hardware and cut a matching thread in the wood with a tap. If you use the clamp parts to make the thread in the wood you will be pressing the thread into the wood fibers instead of cutting and there is a greater risk of splitting the wood.
Bo, I disagree. The threads are shallow enough and the wood flexible enough that the threaded metal parts can safely form their own threads in the wood, with the caveat that the hole isn't too small in the first place. I doubt that any manufacturer of these accessories precuts the threads with a tap.
If by chance the holes are slightly over size, an emergency solution is to coat the threaded portions of the clamp parts with an adhesive such as a binary epoxide resin (that is, two parts need to be mixed together), insert the threaded portions into the holes and wait for the resin to harden. When doing this take good care that the threaded portions are at precisely the right angle relative to the wood, and don't let them move until the resin has hardened, otherwise the chinrest will never fit properly.