Homebrew PCBs

In a message dated 11/30/2003 9:13:18 PM Central Standard Time, 
adam_j_bradley@... writes:
Any other issues that could be causing this?  I suppose the key is super 
sharp bits.  PS: I'm using a 20k RPM 'dremel' like tool and non-tc drill bits 
(yet).  Have yet to find a source for them in Australia.
Adam:  I don't know if the "Dremel" you have is ACTUALLY a Dremel, but the 
couple I have had do not have NEARLY precision bearings to properly drill fine 
holes in glass-epoxy for PC-boards!  I use ONLY carbide "PCB drill-bits", all 
with 1/8" (3.175 mm.) dia. shanks.  Few of these smaller than 3 mm drill-size 
would stand up for long with the junky bearings all the Dremel-like tools I 
have seen running things!  (I built my own "quill" using a 400 Hz precision motor 
and ABEC-7 bearings, with a 1/8" dia. collet).

Also, I drill FIRST (I built my own computer-controlled X-Y PCB-drill rig — I 
am still TRYING to figure out how to upload a photo of it in PHOTOS section 
of this group — for now, I will just e-mail YOU one, separately.   I once 
drilled "after etch", when I didn't have this rig built, but I ALWAYS used 
super-sharp (i.e., "fresh") drill-bits, never DULL ones.  HSS bits will go dull in 
glass-epoxy after two or three holes!  ONLY carbide will work for hundreds of 
holes, and THEN, only in proper equipment, NEVER in a "sloppy" Dremel!  

Sorry, Los Angeles is the closest I have ever been to Australia — oh, wait:  
Is Aquitlapilco, Mexico closer-yet?  So I can't help you with bits.  AND, I 
have bought all I need in boxes of 50, "on sale", when vendors offer them--- 
when a PC-firm resharpens to the point the bits are too short to go through seven 
layers (about 11 or 12 mm.), they are "done" with 'em, and they are offered 
reasonably in boxes of 50.  SAVE all the 1/8" dia. shanks when the delicate bit 
busts off, and re-grind as ENGRAVING bits!  JAMECO and JDR Microdevices are 
two firm-names in L.A., CA (or near there) that come to mind.

Lotsa luck!  Hopefully before I have played my last digerydoo recital, I will 
visit AUS, one day!

Regards!   Jan Rowland


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