What size hole to drill for certain size pins?

[Natlek]

BTW- if any maker needs help in getting the holes line up with round, stag ,taperd tang or jigged materials I can tell you how to do that as well and always have the holes line up, just let me know.

I use same way as you to drill hole in scale , works perfect any time .Last two years super glue is my best friend/assistant for many task For uneven scale I use same way , except I clamp blade at ricasso with two flat piece of steel ..................basically , handle is floating when I drill holes in scale .....

 

[AVigil]

I clamp blade at ricasso with two flat piece of steel ..................basically , handle is floating when I drill holes in scale

Absolutely !

I made a jig and it is invaluable for doing that. I do a lot of tapered tangs and it makes it very easy to get those holes lined up perfectly.

 

[navman]

When I first started doing tapered tangs I tried using shim stock to get aligned pin holes. after two failures (trashing what would have been very nice handle material) I finally built a jig to hold the blade parallel using aluminum plate/block, two long shouldered bolts, wing nuts and the cut off screws with swivel feet from two cheapo HF C-clamps. I super glue the scale to the tang, drill all holes in the material (already have holes drilled in the tang before tapering), reverse, super glue the other scale and follow the holes in the first scale. Works well for me.

 

[Stacy E. Apelt - Bladesmith]

We are all (myself included) getting a bit far afield of the OP request.

Just a reminder that the OP is merely putting new scales on some old knives. He didn't sound like he wanted to build fixtures and drilling jigs. His initial request was what size holes to drill in the wood.