Homebrew PCBs

Thanks, I'll give that a try. My personal experience suggests more a matter of not getting the board really on center than of it wandering off while drilling, but perhaps it is a combination of the two. I know that my equipment could be improved -- I am using a drill press with only 3200 rpm top speed, and there is some runout in the spindle -- and I suspect switching to carbide drill bits would help, IF I used them with a better and faster spindle. The biggest surprise for me is that I am getting usable results, for the most part, in spite of not really having the right equipment on hand.

--- In Homebrew_PCBs@yahoogroups.com, Bruce Parham <obparham@...> wrote:
>
> 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
>