I have seen self tapping screws used extensively: a. to affix thin aluminum name plates onto deliverable units. b. to assemble covers to sheet-metal chassis. In both cases, no flat washers were used. As a matter of fact, in the second case, the screw is supposed to bite into both the metal bodies to achieve valid grounding - in RF applications. Regards, Lakshmi -----Original Message----- From: Crepeau, Phil [mailto:[log in to unmask]] Sent: Thursday, December 04, 2003 8:03 PM To: [log in to unmask] Subject: Re: [TN] Taptite and washers hi, ipc 610 covers all fasteners in the sense that you use whatever the drawing tells you to use. about the only thing it's specific about is that a flat washer needs to be against the laminate that is exposed to a rotating surface on the fastener to prevent the laminate from being damaged. i imagine that the minimum no. of threads that extend beyond the 'tapped' surface could still be used. phil -----Original Message----- From: Torben S. Taustrup [mailto:[log in to unmask]] Sent: Wednesday, December 03, 2003 1:28 AM To: [log in to unmask] Subject: [TN] Taptite and washers Our company has adapted the IPC-A-610C standard. We often use self tapping screws like taptites when mounting PCB's in boxes. In the above mentioned standard this type of screws are not mentioned - only screws with "regular" thread. When using these one or two washers are mandaory depending on the material. My question is, does the IPC standard include self tapping screws? Is it necessary to use washers in connection with self tapping screws? The automobile industry uses a variety of self tapping screws and in most instances no washer is used - and this seems to work fine. Regards Torben Taustrup ---------------------------------------------------------------------------- Torben Taustrup - [log in to unmask] PTA, Technical Assistant / Radio Mechanic Vestas Wind Systems A/S Paludan-Müllers Vej 82, 8200 Århus N Tlf: +45 97 30 40 31 Telefax: +45 97 30 40 01 ---------------------------------------------------------------------------- --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------