spinning the bit fast enough

Ah, yes, I’d forgotten about that. I drill the board with the Sherline’s 10k rpm head, which is too slow by at least a factor of two. Fine-pitch milling would be even worse. I just feed the drill too slowly into the holes, suck up the swarf with the shopvac, and it all works out fine for my simple needs.

I have a dead shopvac that should become a cyclone separator, but that’s far down on the to-do list.

The EMC2/LinuxCNC mailing list routinely features long discussions about which affordable 60k rpm spindles have the fewest warts…

the silver layer is much thinner than the skin depth

Except in high-end audio gear, where anything is possible…

unless you use solder with a few % of silver in it

I’d been using 4% silver, but recently gave up and went back to ordinary 60-40 lead solder. I should try the silver solder again with the Hakko iron, as the failing Weller might have been contributing to the soldering problems.

as the joint has been already made by then…..

And the pictures have been taken!

I’m finding the same sorts of problems you’re talking about wrt getting the board flat and level enough for milling. I’m using a shopvac with a cyclone separator and 2micron filter to catch fiberglass debris, and that’s working well, but getting a flat board (and spinning the bit fast enough to get a good cut surface) is time-consuming.