Homebrew PCBs

Jan,
    The Dremel only costs $59 verses your $400 solution. Please
note this is the Homebrew PCB conference. Cost is everything! It
may be possible to find a surplus dentist drill. I find the Dremel
tool does a great job! I sell the boards I make with mine.


                                         John





--- In Homebrew_PCBs@y..., JanRwl@A... wrote:
> In a message dated 26-May-02 06:09:15 Central Daylight Time, 
> john@k... writes:
> 
> 
> > The problem with Mechanical Etching is the epoxy in the board. 
> 
> Correction, if I dare:  The "epoxy" is merely easy-to-cut "plastic 
stuff"!  
> It is the GLASS FIBER impregnated in the "epoxy" which eats up 
cutting-edges! 
>  
> 
> I suspect the main reason alternatives of pointed "engraving" bits 
is 
> considered here is that such a TINY portion of tool is "in the 
work" at any 
> instant, it therefore has to TURN at such a tremendous speed to 
have any 
> suitable "surface-speed" to work, at all, whereas the CIRCUMFERENCE 
of even a 
> 1/8" dia. bit would have much more surface-speed, even at slower 
RPM.  That's 
> why a modern dental hand-piece turns those tiny "burrs" (mill-
bits!) at 
> 100,000-300,000 RPM and more!).  Tip:  Dentists typically throw-out 
used 
> burrs, even if only "package opened, but not actually used".  Next 
time you 
> have 3 grams of amalgam put in  your face, ask the dentist if you 
can HAVE 
> "your" used burrs (you HAVE paid for them, after all!).  These will 
> (usually?) have 0.0625" dia. shanks, yes, even those built-in and 
USED-in the 
> rest of the world, I think!  So, you will have to use the correct 
collet, 
> etc.  But those can probably do "mechanical PCB etching" very well, 
if turned 
> at least 30,000 rpm or more.  Think AIR-MOTORS!!!  Whew, even if 
the "main 
> spindle-bearing" were dual-race angular contact ball-bearing, 
a "Dremel tool" 
> just isn't the kind of "quill motor" for a PCB drill!
> 
> 
> [Non-text portions of this message have been removed]