They were mainly for watches as were other miniture threads. Other uses were instrumentation. Whitworth goes down to 10 thou OD. Waltham and Thury also have threads in that range. Heck, I bet the taps break when you look at them! lol Alan Stepney http://www.alanstepney.info Model Engineering & steam engine information pages ----- Original Message ----- From: "Bede McCormack" <bede@xxxxxxx> To: <modeleng@xxxxxxxxxxxxx> Sent: Friday, December 22, 2006 7:29 AM Subject: [modeleng] Re: BA/ME Thread Query Recent searches for thread types turned up a list of BA threads that went all the way to 25BA with a tpi count of several hundred if I remember correctly (can't find the list again of course!). Surely this must be a theoretical fastener, unless nanotechnology has found a use for it? I imagine even the most cross-eyed watchmaker would be hard put to thread that one... But just out of curiosity, is anyone aware of a use for such a miniscule screw? Bede McCormack Brooklyn On Dec 20, 2006, at 2:41 PM, peter.chadwick@xxxxxxxxxxx wrote: > It seems to be the season for finding strange threads. I went to use an > Italian made variable capacitor this afternoon. No nut for the > mounting > thread. Investigate, and the damn thing is 11mm diameter, 1mm pitch!!! > That's not in any table I've found................. > > Gave up. Spent 2 hours in turning etc to make a new bush, threaded > 3/8-32tpi and suitably bored to make a seating for the ball bearings. A > very moot point whether or not making a small enough boring tool to > cut an > inside thread to fit would have been quicker. With my standard of > workmanship - most unlikely! > > Peter Chadwick > Swindon > > MODEL ENGINEERING DISCUSSION LIST. > > To UNSUBSCRIBE from this list, send a blank email to, > modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the > subject line. > MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line. -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.15.25/593 - Release Date: 19/12/2006 13:17 MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.