You can easily resharpen HSS bits, even the very small ones. Don't fuss about the correct geometry, almost anything will melt through FR4. You can just touch them against a dremel wheel or grinder at what you imagine might be the correct angle and you are good to go for another couple dozen holes. I didn't even take them out of the drill to sharpen, gives you something to hold onto.
As for carbide, they do work great in a fast running drill in a precision stand. There are several ways to make a stand using a pivoting arm or flexures. Highly recommended if you make a lot of PCBs because of the clean holes they cut.
BigClive (.com and youtube) uses carbide drills handheld, but then he has hands the size of manhole covers, and is a scot....
ST
On Sun, Feb 14, 2016 at 7:59 PM, bobledoux@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
While I can find resharpened carbide bits, those cheap, bench drill presses tend to have too much runout. They also run too slow for carbide. As a result carbide bits tend to break.
I prefer to use high speed steel bits. They don't break. They do wear quickly, but I can finish a typical board with just one bit. My preferred size is 1/32 (.032) inch as these tend to cost less than numbered bits. Places like Enco sell these at 65 cents a piece in lots of a dozen plus postage, of course.
Looking for a local, and lower cost supply, I looked to Harbor Freight. They sell a 30 piece drill bit set for $3.99. The set is metric sized, but very useful. Converted to inches the set includes five each of .020, .024, ,031; three size .039; and two each of .047, .059, .071, .079, .093 and 118.
For circuit board work, the 18 bits less than .040 size are a bargain at 22 cents each.
In keeping with the K7QO experimental mindset, I'll buy some tomorrow and report back.
bob-N7SUR