Thanks to all that responded to my question.  I have listed all the responses
and will summarize.

Fabricators for the most part drill all holes at first drill tenting
nonplated holes.

One response stated that 2 files is prefered because of producability analysis software.
This is how this all got started by the way.

Others are OK with 1 file as long as the drills are well marked as plated or nonplated.

My conclusion is that 1 clearly defined drill file is what is expected from most fabricators.
If the producability analysis software needs two files it can be seperated easily enough.

-John

Begin included messages

     Since the effort is made to drill as many of the holes in the
     primary drill operation as possible, we prefer that the drill
     be sent as one file to reduce the number of steps in the
     CAM operation. Non-plated holes are only drilled in a
     secondary operation if they cannot be tented in the imaging
     plating operation.
     Don Bloye
     PC World


one is fine as long as you use a seperate tool for pth and npth.
I edit the mfg file to signify npth holes.
Ed Current


Just a word of warning, there have been several TechNet  e mails about this 
first drill approach being dangerous if an alternative to electroless copper 
system is in use and any circuitry does not have a clearance around the 
nonplated hole as the alternatives do leave the hole with a unremoved 
conductive layer that can result in leakage.  Reportedly it is not like the 
electroless where you can remove all the plating.
Edwards, Ted A



     Outputting plate through and non-plate through drills in separate 
     files will work the best for most fabricators.  The main reason is 
     that most fabricators are using producability analysis software.  This 
     software applies different "rules" for analyzing the different hole 
     types with regard to spacing, clearances, etc....  It will also save 
     the input people time in not having to individually differentiate the 
     hole types and it eliminates the possibility of input errors.  The 
     fabricators will then generally combine the two files so all holes are 
     put in during primary drill.
     Hope this helps,
     Scott Baller


The problem of conductive material remaining in the non pth holes on direct 
plate systems does not exist for carbon because all conductivity is eliminated 
in the dry film stripper after plating. As long as the holes can be tented both 
sides they can be drilled with the pth holes. Palladium systems would be the 
same as electroless copper and the palladium layer would be removed in the 
etching process.
Paul Gould



On a related note, many design texts suggest using unplated .125 
tooling holes on every design, but our lead designer here wants 
to try to make ALL HOLES PLATED on our designs because he heard 
that it saves processing steps. When I asked a board vendor about 
it, he said it USED to be true that more steps were needed for 
designs with unplated holes, but not anymore. 
There are designs where I need unplated holes, no matter how much 
more difficult it is for the fab house, but other designs could 
go either way (no tooling holes on hand-assembled boards, for 
example). Does it really make a difference to the fabricators?
Also, I have never heard of sending two drill files... do people 
really do that?
confused by too many opinions and no facts...		Jack
Jack Olson


Makes no difference as long as they are clearly marked.  I have more
problems with people not senting drill maps or drill tool sizes and
counts than seperating pth and npth..We(fabricators) will drill them
primary if at all possible and only use a secound operation in extreme
situations..it is more costly and just a pain...

Doug Jeffery

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