Can the item in which the screw is to be inserted give any clues? Do you know where and when it was made? Are there any other fasteners on it that can be removed and measured?

Have you considered M1.4 x 0.3 as a long shot? With something that small, you should ask how he has arrived at those dimensions (e.g. thread gauge and loupe for pitch, micrometer for major dia.) and use the answer to assess which of the two offers opportunity for error or confusion.

Dell

According to the incredible thread list produced by Andy Pugh :-

No 12 Progress is 1.2 mm Ø by 0.3 mm pitch.

Not a thread series I knew of or have encountered but a quick Google this link which includes a tabulation of sizes :- **LINK**

https://www.sizes.com/tools/thread_progress.htm

"A thread series used in watchmaking in Switzerland, 19ᵗʰ – 20ᵗʰ centuries. According to de Carle, “the most popular modern Swiss screw thread.” As is obvious from the table below, the size number is the diameter in tenths of a millimeter. Thread angle, 50 degrees; depth of thread, 0.8 pitch. Depth of rounding, 0.093 × pitch; radius, 0.0732 × pitch.

The company sold ready-made screws, and issued a screw plate as a means of checking sizes. Much of the use of the series occurred when makers found it convenient to thread their own screws using the screwplate as a die."

Clearly legit but possibly old enough to be obsolete and, presumably, screws may be unobtanium off the shelf.

Clive

Edited By Clive Foster on 23/09/2022 20:12:27

Should also add, Lowenherz Ø1.4 has a pitch of 0.3mm.

Martin C

Edited By Martin Connelly on 23/09/2022 20:46:40

Hi alI,

hope that I'm not jijacking this thread, forgive me if I am. I need to know what threads are in the various bushes on a Stuart Turner 504 boiler. I'm not sure if the modern Stuart version has the same threads as the older ST one, perhaps someone could enlighten me?

Best regards

TerryD