That's about 400 times the DIYer must manually centre a punch or bit. 400 tedious chances to screw up.
Maybe better first invest the time to make a one-shot incremental drilling jig for the purpose?
That could just be using cheater sticks (what you might know as setup blocks) - 1/4" spacing is it? Drill the centre, then shim with things of consistent thickness to proceed from there.
Or better use a pin or two. I do this of course cutting rows of box joints on a tablesaw. Otherwise I'd be squinting at a line for every cut! I've used alignment pins for drilling copper blocks too, though not in making drilled channels.
For your block the pin must point down, like a second drill bit. One could use some cut-offs from the copper, plus a few scraps of paper, to raise a clamped metal strap (perhaps another piece from the same material) with a pin hole through it. This hole would be 1/4" from the drill centre, and the same diameter as the bit. Now, once the first hole is drilled, it may be aligned under the pin hole, secured with a pin, and new holes drilled at repeatable distance. The maximum error between two holes is the runout or pin slop times two - far less than doing anything manually. Drill a few, and two pins are possible.
|