What is the tightest tolerance that can be held on a non-plated hole relative to the fine pitch artwork pattern on one of the external layers, this could be a dimension od around an inch to 5 inches approximately I am trying to locate a hole within +/-.0015" of a artwork pad that is sized .006"x.098" , this is connector pattern of around 300 to 400 pads at a pitch of .31mm Which method of drilling would work best for this, primary drill operation or a secondary drill after the outer layer has been etched? The pcbs are both rigid and rigid flex polyimide class 3 designs. Thanks in advance, Mike --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------