Homebrew PCBs

Just grinding a point then cutting off half the bit won't work as the 
cutter would have no clearance angle. You would get a really rough cut 
and quite likely snap the tip off the cutter. Grinding the flat is a 
pain as you need to remove a relatively large amount of material and you 
need to be quite accurate. This page gives some great info 
<http://www.antaresinc.net/FactAnatomy.html>. Note that you need a 
fairly fine diamond wheel to get a good enough finish. If you don't 
already have a wheel and a suitable grinder it is far cheaper to buy the 
cutters than make them.  Considering the price of new cutters on eBay it 
is not really worth the effort to make them in my opinion.

If you have a suitable diamond wheel it is worth resharpening cutters as 
they wear out quite quickly. My grinding fixture is really simple but 
works well. I have a mount that has a 1/8" hole bored in it. This is 
bolted to my tool and cutter grinder and supports the cutter. I then 
clamp a collet to the cutter. The collet has an arm sticking out of it 
which I use to rotate the cutter. I have a stop that locates on the arm 
and prevents me from rotating the cutter too far. The position of this 
stop controls the clearance angle.  Once set up it takes about a minute 
to sharpen  a cutter.

Les


On 09/03/2013 08:16, Boman33 wrote:
> Recently I remember an article about using broken PCB carbide drilling bits
> to make V tipped router bits.  Basically grind the desired angle and then
> grind off half the bit.  There was a careful procedure to allow accurate and
> good performance.
>
>   
>
> I have googled, hunted in the email lists, and my own computer without
> success.
>
> Any suggestions where I can find it?
>
>