Re: Leadscrews, PCB router experiment

Hi Jon,

Carbide drills like these:

http://www.thinktink.com/cgi-bin/carbide.cgi?page=imperial&step=10&start=88

It's the Think and tinker URL. They have a $50 minimum, so I'll need to
get the ME bits too!

I bought some surplus PCB drills at Haltek when they were still there.
How do I know if they're carbide or not?

Alan KM6VV


Jon Elson wrote:

>
> 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