Homebrew PCBs

In a message dated 6/13/2004 12:13:09 PM Central Standard Time, 
dg140@freenet.carleton.ca writes:
While drilling Many small holes in PCBS--or any plastic or plexiglass for that
matter--it seems that the bit will become coated with plastics. 

Charles:  No.  The material does NOT do this.  Of course, the bits must be 
clean and sharp at the outset, but a good sharp carbide bit will not accumulate 
either copper nor glass-epoxy, perhaps partly as the two are not MISCIBLE.

You should find a "local PCB house" and get invited to come see their 
Excellon (or whichever) CNC PCB-drill going at it!  It will blow you away!   And they 
can show you their NEW bit-inventory and the USED-BUT-STILL-USEABLE 
bit-inventory, and discuss with you whether they sharpen ("recondition") or just throw 
OUT the used bits (Some GOOD houses do BOTH!).

If you watch for goodies, you MIGHT discover, as I did, that they TRASH 
anything 4" and narrower.  I got enough FR-4 between 4.25" and 3.8" to last ME for 
a long, long time in my home-brew stuff, last time I visited the local 
"house"!  Of course, most of it is only ½-oz., but it's still good enough for 
tinkering!

Jan Rowland


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