Randy, Been there, same problem with a .125" tooling hole plated through, but covered with soldermask over the annular grounding "doughnut" on the bottomside, which was .325" in diameter if I remember correctly. I fixed these in the following manner. I set up a frame clamp in a CNC router, a precision router. I used a cylindrical sanding block which was just a .325" diameter cylinder with a 6/32 (I think) center hole tapped and countersunk in the bottom of it. At the top of the cylinder on the side there was a set-screw that securely held a .250" shaft protruding out of the cylinder top, which was used to hold the cylinder in the router. I purchased emery pads for a Dremel tool (rough or medium) and secured them in the tapped and countersunk hole with a screw that when tightened was recessed below the surface of the bottom of the cylinder. I then was able to literally sand away the solder mask so the grounding doughnut was exposed. The drill needs to be an automatic mill or drill that can come down precisely the same Z-axis depth every time. The sander could do about 10-12 pwbs with 4 holes per board before the emery pad needed to be replaced. When finished we applied solder paste by adding the doughnut aperture to the bottom-side stencil. It took us two 8-hour shifts to get the boards ready for regular production, but we did not lose a single board. It took remarkably little pressure to obliterate the 5-mil thick solder mask. We just basically came down and touched each spot for a couple of seconds at the most. At that time nobody cared about whether or not the solder mask dust was hazardous, and I don't know if it is, but you probably would want to set up a vacuum blower to contain it. The part I do not know is your internal hole size. The retaining screw head and countersunken area must be smaller than that. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Randy Bock Sr. Sent: Thursday, November 10, 2005 1:53 PM To: [log in to unmask] Subject: [TN] Solder Mask Removal Hey y'all, We have several hundred boards that are supposed to have the solder mask removed for around a mounting hole on the back side of the board. The fab house missed. We are faced with a total remake if I cannot find some way to remove the solder mask relatively easy. Most are still fab boards, but I do have some that are assembled. Any ideas would be appreciated. The clear area has to be approx 1/2 " dia. (is for grounding) Randy Bock Sr. Quality Engineer Pitney Bowes AddressRight Printers (email) [log in to unmask] Newtown Building 2 203 270-4931 Ext 8-426-4931 In 203 270-4982 Fax --------------------------------------------------- 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- 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 847-615-7100 ext.2815 -----------------------------------------------------