Re: [CAD_CAM_EDM_DRO] Re: Leadscrews, PCB router experiment

Alan Marconett KM6VV wrote:

> Hi Bob,
>
> I haven't done ANY yet! I bought an engraver 'V' bit, and I'm hoping to
> use that. I like the idea of using a starter hole; that would be
> "spotted" with the 'V' bit? I would be drilling the holes with the same
> setup, not as a separate operation (just change the bits).

I use solid carbide drill bits specifically made for PCB drilling. They
really
don't like anthing that tries to make them bend. So, there is some risk
in putting centering holes in the copper. The carbide drills really won't
follow them anyway, bit it could cause the drill to bend slightly as it goes
through the copper, and then put more side stress on the drill bit as it
continues through the material. If your machine is highly repeatable,
then this won't matter. But, the solid cabide drills will drill the hole
right
where the spindle is, so you don't NEED a centering hole.

The HSS drill bits are awful, and you are lucky to get 100 holes per bit
with them.

Jon