Homebrew PCBs

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
>