Homebrew PCBs

I use a Dremel to do my drilling by hand.  What does everyone use for 
bits?  i found a nice Dremel brand engraver bit that drills fairly 
small holes well, but not as small as my vias.  

Also are you drilling before etching, after etching?  Do you etch the 
hole in the pads to guide the drill bit or not?  I seem to rip alot of 
pads off during the drilling itself on both sides >< .

On Sat, 29 Oct 2005 05:45:56 +0200, matt clement <buckeyes1997@...>  
wrote:

>
> Also are you drilling before etching, after etching?  Do you etch the
> hole in the pads to guide the drill bit or not?  I seem to rip alot of
> pads off during the drilling itself on both sides >< .


Your pads are too small. They are probably sized for throughhole plated  
boards, where the plating "rivets" them together. For homerew boards you  
need large pads. Make them oblong on stuff with tight spacing (i use  
1.6mx4mm for DIL ICs.). Now they will not rip off any more, and actually  
support a component as well.

I drill after etching, the drilling seems to rip off small pieces of toner  
around the hole. If you can drill before transfer (of any kind), like with  
a CNC, this is not an issue as the resist is put on after the hole is  
complete (that's what pro shops do).

I etch out the hole in the center, but smaller than the real thing (my  
software has a checkbox "guide holes only" when printing.


As for size, i use 0.8mm for most, also some 0.6 and 1.0 and 1.2 and 1.5mm.

ST

----- Original Message ----- 

From: "matt clement" <buckeyes1997@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, October 29, 2005 3:45 AM
Subject: [Homebrew_PCBs] Drill sizes for Dremel


>I use a Dremel to do my drilling by hand.  What does everyone use for
> bits?  i found a nice Dremel brand engraver bit that drills fairly
> small holes well, but not as small as my vias.
>
> Also are you drilling before etching, after etching?  Do you etch the
> hole in the pads to guide the drill bit or not?  I seem to rip alot of
> pads off during the drilling itself on both sides >< .

I drill after etching (boards are resist-coated) and have holes in the pads. 
I use 0.8 mm tungsten carbide drills and the highest possible drill speed 
(Minicraft drill and stand).

Leon
--
Leon Heller, G1HSM
leon.heller@...
http://www.geocities.com/leon_heller 

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matt clement wrote:

>I use a Dremel to do my drilling by hand.  What does everyone use for 
>bits?  i found a nice Dremel brand engraver bit that drills fairly 
>small holes well, but not as small as my vias.  
>
>  
>
 Leave a little space to one side of your vias, and you can just drill the board beside them and bend the wire over on them, after etching.  I rarely drill a hole on the pad for hand made vias etc, into the bare board works just as well.  Nothing says it has to be into the pad, as long as you make the connection..

Alan