Homebrew PCBs

In a message dated 5/18/2003 9:32:17 AM Central Standard Time, 
stefan_trethan@... writes:

> any new and nice ideas are very welcome. 
> 
> 
> have all of you professional pcb drill presses or how do you drill your 
> boards? (maybe homebuilt ones and a picture of them???)
> 
> regrinding drill bits (for pcb) should be possible with a small diamond 
> wheel?  is this true / is this possible &good for one who can regrind a 
> normal drill bit so that it works again? 

Stephan:  

To your first question:  WOW, you would be talking close to $100,000 (U.S.!) 
for a "professional PCB drill press", I think!  At least the one CNC 4-quill 
job I saw in operation at a local PCB shop.  Now, if you mean just a manual 
drill-press one could use to MANUALLY drill a prototype board, I have never 
seen one with an adequate-quality quill.  The quill-bearings would have to be 
at least ABEC-7 for that!  I bought ONE such bearing to rebuild a tiny 400 
Hz/3-Ø motor I used to MAKE a PCB-drill, and WOW, talk about PRICEY!  The 
precision and concentricity of a quill must be MIND-BOGGLINGLY close to give 
ANY life at all to PCB-drills!  And the "attack" and feed-rate must be 
properly set, as well.  

Yes, PCB drills ARE re-sharpened with small diamond wheels, but again, you 
are talking about some very fine drill-bit tipping equipment, NOT just the 
diamond-wheel!  The results you can get from manually touching a tip to a 
diamond-wheel on a small "grinder motor" will vary so wildly you will wonder 
if any "sharpening" is taking place, at all!  

Now, the frustration of the first ¶ above inspired ME to brew my OWN "PCB 
Drill", and control that with a now-LONG-discontinued CBM "PET" computer (see 
photo).  But I did that in '84!  Were I to do another (or rebuild that one, 
when it finally fails, which may be soon!  Argh!), I would design the 
"electronics" to work with a "PC", as those can be had now for less than the 
postage necessary to GET them delivered to the door!  

So look at the photo:   <A HREF="http://photos.groups.yahoo.com/group/cad_cam_edm_dro/vwp?.dir=/Home-brew+CNC+lathe&.src=gr&.dnm=PET-Controlled+X-Y+PCB-Drill.jpg&.view=t&.done=http%3a//photos.groups.yahoo.com/group/cad_cam_edm_dro/lst%3f%26.dir=/Home-brew%2bCNC%2blathe%26.src=gr%26.view=t">PET-Controlled X-Y PCB-Drill</A> 


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