Homebrew PCBs

Can I conclude, from the lack of choices for 1/8" shank center drills or 
countersinks, that center drilling the itty-bitty PCB holes isn't popular 
practice? Too dumb a question to bother answering?

Hello,

It's not a dumb question; such small centerdrills and C/S's DO exist. 
But you are correct, for PCB work the hole is simply drilled in one 
pass with a single bit.

The small tooling (C/D's and C/S's) is for machining other materials.
micro100 is one source.

Ballendo 

--- In Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@s...> 
wrote:
>
> Can I conclude, from the lack of choices for 1/8" shank center 
drills or 
> countersinks, that center drilling the itty-bitty PCB holes isn't 
popular 
> practice? Too dumb a question to bother answering?
>

On Wed, 09 Nov 2005 09:46:11 +0100, Mike Young <mikewhy@...>  
wrote:

> Can I conclude, from the lack of choices for 1/8" shank center drills or
> countersinks, that center drilling the itty-bitty PCB holes isn't popular
> practice? Too dumb a question to bother answering?


nobody seems to do it, no.

With the carbide bits running at high RPM they will usually easily center  
the hole without any wandering. It isn't even preferrable to have a  
pre-drilled hole, as enlarging it puts much more stress on the drill  
(without limited feedrate that is), it tries to take out much larger  
pieces because it isn't held up by the center stuff. I've broken some when  
enlarging holes.

Sometimes when i need really large holes, like for mounting, i drill the  
center with like 1mm and then enlarge them on the big drill press.


Countersinking isn't really desireable either, but i have seen sinks with  
the right shank on ebay, made of carbide. A sharp carbide drill doesn't  
leave much burr and they surely weren't used to countersink component  
holes.

ST

--- In Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@s...> wrote:
>
> Can I conclude, from the lack of choices for 1/8" shank center drills 
or 
> countersinks, that center drilling the itty-bitty PCB holes isn't 
popular 
> practice? Too dumb a question to bother answering?
>

When printing the board you can add a cenre hole by making the 
component pad a donunt.  The slight raise in the copper makes it 
possible to centre the pcb drill when working without a drill press.  
Without the donut is is very hard to keep the bit on track.

Mike

mikegw20 wrote:

>--- In Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@s...> wrote:
>  
>
>>Can I conclude, from the lack of choices for 1/8" shank center drills 
>>    
>>
>When printing the board you can add a cenre hole by making the 
>component pad a donunt.  The slight raise in the copper makes it 
>possible to centre the pcb drill when working without a drill press.  
>Without the donut is is very hard to keep the bit on track.
>  
>

  Yep small holes in pads do wonders for doing it by hand.  Even leave a 
small ring where you just want a hole, and eat away the copper as you drill.

  Reason for no choices in drill bits by hand?  Likely only 1 in 1, 10, 
or 100 million holes is done by hand.  Everyone in the US uses dozens of 
items with hundreds of holes in PCBs each the percentage of people who 
ever even use one of these type bits by hand even once is near zero.  
Only money for these bits is in commercial use, and there it's 100% 
automated.  Near absolute zero need for what you're wanting..

  Plus I'm sure someone has some somewhere, finding and getting and not 
costing $20 each are all different stories though..  Look Asian, most 
PCBs are manufactured there..

Alan