Hi there! I'm confused with this one... I've got these plywood squares that I had to drill a bunch of holes in. Despite using a low speed on my drill and adding masking tape (below) there's still pretty nasty tear out on nearly all holes. (EDIT: These are not through holes, this is for crochet square blocking boards. Metal rods which need to stay in place are put into the holes.)
And this is it after removing the masking tape.
What should I do? Thanks in advance!
Sharper drill bit. Play with higher speeds and lower feeds. As said, backer.
This is a little bit like drilling shelf pins holes, of which I've done a lot. The thing that ends up working best for me is a plunge router in a jig with a solid carbide down spiral bit. Those are not through holes, though.
I failed to clarify properly, but these are actually not through holes too. The router sounds like a good idea - these blocks are about 10cm x 10cm though, would you still be able to do it with your jig without the router tipping?
Either make the holes before cutting out the blocks or make the jig to hold the block.
My shelf pin jig makes holes about 4" apart about 2" from the edge of the board, so it wouldn't work for your application. You could certainly make a router jig for your needs though.
Mine is a small plunge router. There are a number of them on the market that should work. Make sure that you can get the bit you need before getting too invested in this idea.