Jack, Check out IPC-2222 9.1.4 (published Feb. 1998) It basicly states that nonfuntional lands should be included on internal layers for all plated through holes -.... but greater than 10 layers, or where electrical requirements don't permit, it is okay to remove some of them.... (my interpretation). I also recently took a class where they talked about leaving them, but I can't remember what the reasoning was -but we did make the change. Lynn Isaacson Medtronic Physio Control ################################################################ 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################