First of all I stay with the "Class 3 Military" , internal .002, external .004.
What you need to know is, what size tool is my vendor using to achive
the called out finished hole size? 

For a plated through hole:
     MAX. ACCEPTABLE HOLE DIA. +.003" = (MAX TOOL SIZE)
     MIN. ACCEPTABLE HOLE DIA. +.008 = (MIN. TOOL SIZE)
EX:  PTH .028" +/- .003" (MAX. TOOL = .034") (MIN. TOOL = .033")

Now I  need a list of avable tool sizes from my vendor(s) and a find the
max. tool that they would/could use. (.033") and plug that into this
formula:

     Min. Pad = (AR + .005") x 2 + Drill Size

EX: .002" AR = (.002" + .005") x 2 + .033" = .047" PAD

Clear as mud?

Dan Lorinser
BFGoodrich Aerospace

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