Homebrew PCBs

awakephd wrote:
> In my relatively limited experience, one of the key factors is how precisely you can drill. My most recent board has .045 diameter via pads, drilled with a .6mm drill (0.024"). Even though I managed to get the registration between the top and bottom more or less perfect as far as the toner transfer and etch, I discovered that it was easy to drill the holes at an angle, at least using HSS drill bits. The drill is so small that it bends very easily; you can be off-center just a bit; the bit goes in right (because of the little etched dimple created by my software), but it comes out in the wrong place.
>
> Obviously, I need to work on my drilling, both equipment and technique!
>
>   
The trick is to not try to drill the whole thing in one pass; the tip 
gets loaded and will wander off course.
Take a few 'pecks' with each only going 5-10 mils deeper while backing 
the bit completely out between
each peck and don't feed in too fast.

This is the technique used on NC machines to drill really fine (6 mil) 
holes through 60 mil boards.

Bruce