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 *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************