Homebrew PCBs

I 100% agree that it is not cost-effective to grind my own bits but I like
to know to be able to do it in an emergency while waiting for bits to
arrive.

Bertho

 

From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of Les Newell
Sent: Monday, March 11, 2013 08:19
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] PCB Milling bits

 

  

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?
>
> 





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