At 08:03 PM 5/11/2005 -0500, you wrote:
>If I understand you correctly, you will need to edit the drill rack file
>(.drl) to list only the sizes you want to be drilled.  When you run the CAM
>processor, it will complain of a missing drill size, so you need to specify a
>drill tolerance so that it will find a close enough drill from what's
>available.  In the example you listed, a -1% should be enough.
>
>When you get the gerber outputs, examine them carefully to ensure the 
>affected
>holes/pads are acceptable in terms of size, annular ring, etc.  Also, the
>.dri file will report the substituted drills.
>
>Yes, the central position will be the same, but the diameter will be
>different.
>
>BTW, I would think that you would specify a tolerance *above* any missing
>drills, so the components will fit, unless you've verified otherwise.
>
>Cheers,
>-Neil.

Don't know about Eagle, but in general, I've had no trouble manually editing
Excellon drill files for prototypes to use standard drill racks. They don't
seem to care if two tools are the same. Of course I check it very carefully
afterwards, and before sending it off. In particular, run a DRC
on your minimum annular ring design rule to make sure you're not violating
it due to making the drill size too large.


Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
Inexpensive test equipment & parts http://search.ebay.com/_W0QQsassZspeff




-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist