Re: PCB drill working

[mjmahon@aol.com (Michael J. Mahon)]

Hilary M. Turner replied:

>   An easier was attach a micro switch with an adjustable length up the side
>of the drill so you can adjust the depth to which the drill will drill to.
>Use
>a scrap piece of whatever you what to drill and make several cuts to achieve
>the right depth . K.I.S.S.
>Hilarious
>
>"Michael J. Mahon" wrote:
>
>> Rich J.replied:
>>
>> >"Mark Cummings" <NOTfigjams@primus.com.au> wrote in message
>> >news:<3b1b8703@news.iprimus.com.au>...
>> >> For that to work you will have to sit the PCB up off the cutting table a
>> >bit
>> >> using some kind of spacer, to allow for the tapered end of the drill
>bit,
>> >> otherwise your holes will not be complete.
>> >
>> >Yes, that is a good point.  A spacer the thickness of the distance
>> >from the tip of the bit to where the taper ends.  I may add some sort
>> >of microswitch or encoder to get drill depth feedback from the plotter.
>>
>> Or, even simpler, without a spacer, note the time from "drill start" to
>> "first contact", then add a small fudge factor (like 10%) to clear the
>> hole.  Now that I think about it, if the variation in drilling time is due
>> to board thickness rather than board hardness, then the fudge amount
>> should be a fixed add-on, rather than a percentage, since it's determined
>> by the bit geometry, not the board thickness.
>>
>> -michael

It just "shows to go you"--I always think that a software fix is simpler!  ;-)
But I do like removing the need for a metallic underlay.  Of course,
_something's_ going to have to go on top of the plotter bed, unless it's
going to get drilled to oblivion!

-michael

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