Here is a simple fixture for drilling tapered tang scales that I copied fom another.

[LARRYZ10]

Here is a simple fixture that I copied from Knife Maker David Sharp. I have seen similar ones from many makers but this one is easy and uses a machinist's "123 block" and some aluminum . The cap crews are 5/16ths by 18 thread 2.5 inches long and the drill for the tap is a letter F which I think is close to a 17/64 drill. I drilled the top plate with a 3/8 drill for easy turning of the cap screws with only your hands and not a wrench. Seems to work very well. I will cut a small piece of Lucite or G10 on a slant to slide under the bottom scale and support it for drilling. It is heavier than it looks so is very solid. Larry