Quoted from jibmums:I have a ball guide hole that I need to redrill on my Space Invaders playfield. I've already filled it with epoxy and drilled it once, thinking I was drilliing it straight in, only to find that the hole was at enough of an angle that I had to refill with epoxy and start over. How would go about making sure that my drill is held perpendicular to the playfield (which, I should add, is still otherwise fully populated and in the game)?
Maybe something like this: