Homebrew PCBs

LOL!  

I can just picture me standing in front of a grinder today (with my 
bad eyesight) trying to hand grind a point on a .035" carbide drill 
bit :-)  I can barely grind the .250" drill bits anymore :-(

The more I think about it though, I am going to pick up either a 
soft-green wheel or a diamond wheel.  I plan on giving the isolation 
milling a try when I get the little machine done (sometime during 
the next century).  I suppose someone makes bits for isolation 
milling but I have not seen any in the grab-bags of bits I have been 
buying.

So, in the spirit of doing everything else, why not make an attempt 
at grinding tiny bits to drive myself crazy ;-)

Chris



--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@...> wrote:
>
> On Tue, 25 Jul 2006 21:53:31 +0200, lcdpublishing  
> <lcdpublishing@...> wrote:
> 
> > Yeah, I should keep the broken ones, if for nothing else, to sell
> > for scrap value.  I don't have any means of repointing or even
> > grinding carbide here.  I do have enough grinders I suppose that 
I
> > could put a soft wheel or a diamond wheel on somthing though.  I
> > guess I better start saving them!
> 
> 
> When i was at school we made scribe tips out of them broken ones. 
Still  
> have mine somewhere, it will work as a glass cutter ;-)
> 
> There were PCB drills with a soft shank where they could cut a 
thread for  
> screw-in tip replacement. But at some point they made them solid 
carbide.
> 
> I keep them all, but have yet to find a good use (lacking a 
diamond wheel  
> too).
> 
> However, if you break one by chance with a short section of drill 
spiral  
> remaining they can be used to drill or enlage holes in populated 
boards  
> "freehand" where a normal length drill would break. I wish they'd 
make  
> them with only 2mm or 3mm of thin end. They'd never break! Conrad  
> Electronics from germany used to sell spear shaped bits like that, 
not  
> sure if they still do.
> It might be possible to grind them shorter, but maybe it is too 
tricky to  
> do by hand (although i'm usually fairly good at drill grinding)
> 
> Anyway, with the pivoting drill press i managed to make some quite 
dull  
> before breaking them.
> 
> St
>