All, I luckely found some calculations for determining pin deflection, hole diameter, pin length, hold (yes HOLD) diameter, etc. for Testing Fine pitch devices (.010", .012") and BGAs. Is anyone familiar with these formulas? HSmin = SD + PT (tanO) 0 = sin-1 (Pd/Pl) HSmin = (SD + PT)(PD/PL) LEGEND HSmin - min hold diameter SD - shaft diameter PT - plating thickness 0 - angle of deflection PD - pin deflection PL - pin length Can I use these formulas to determine if testability is feasible, for a very high dense assembly {4 - 600 I/O BGAs with 30 - .020" pitch devices (160-pin nominal) in a 9 x 7 form factor}. I feel I am missing several pieces to the overall formula picture. Can someone advise where I can obtain the rest of the equation. John Gulley ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################