Diamond burrs are for cutting Glass (window glass) not epoxy glass.
These bits will not work well at all on anything else. There is a
guy on Ebay that sells boxes of drill bits for PCBs - that might be
a better start for you - however, don't try to drill holes without a
drill press. Carbide drill bits are very brittle and will break
quickly if drilling by hand.
Chriss
--- In
Homebrew_PCBs@yahoogroups.com, "soffee83" <soffee83@y...>
wrote:
>
> Hi again!
>
> I recently received a ridiculous quantity of some suspiciously
> inexpensive 0.9mm diamond burrs I won on eBay.
>
> http://tinyurl.com/cncw6
>
> I don't have any serious board drilling on the agenda, but I tried
a
> bunch of test holes and it doesn't look too promising-
>
> On the first couple holes the bit feels as if it's "burning" it's
way
> through the PCB with some unfamiliar looking debris being tossed
out
> of the cut. I actually had to remove and examine the bit with a
> magnifying glass to see if it had anything that looked like
cutters. I
> tried another with the same result. They had to feed extremely
slow
> due to the "not so clean" cut and I actually broke two tips by not
> giving them the time to "burn" through. They also leave a nasty
raised
> lip around the entry and exit holes, which would imply that
they're
> pushing rather than cutting their way through.
>
> I had used a Dremel diamond burr for a long time, but eventually
> dulled it on something or chipped it's cutters. I got another one
not
> long ago and did something stupid in a hurry (side to side
pressure),
> which broke the ball off. IIRC- They cut quite nicely, however,
they
> were around 2.5mm, which wasn't too good for smaller stuff, plus I
> think they were 5 or 6 bucks a pop.
>
> Does anyone else here use dental burrs for their drill work. If
so,
> how quick and clean of a cut are you usually getting?
>
> That seller had about 650 profile hits, all positive, and states
that
> the bits are all top quality, just with no names. Some of the
feedback
> even praised the quality of them. (??)
>
> Regardless of what ends up happening with these, I was sort of in
a
> pinch. I don't like the idea of buying one or two non-standard
micro
> small bits locally and the 5 pack of mini Dremel drill bits (in a
> glass tube) is no longer around here.
>
> How are the rest of you guys stocking up, and from where?
>
> -Thanks Again!
> George
>