daimlersteve wrote: ↑Tue Oct 08, 2019 9:51 am Anyone --- Thread ?

As well as UNC and UNF the Unified thread system also specifies UNS (special) threads for use where the other sizes are not acceptable. The finest standard pitch for a 3/4" UNS is 27 tpi. If your thread is definitely 28 tpi then it could be from the Unified constant pitch series. These threads, specified as UN, are based on pitches 4, 6, 8, 12, 16, 20, 28, and 32 tpi and apply to a range of diameters, including 3/4". These are used in applications where the design considerations exclude the other series.

By the 1950's the Unified series fasteners were in almost exclusive use in the motor and other industries, so a probable match for your thread would be 3/4"-28 UN. As for all Unified threads the flank angle is 60°.

beauty, thanks Nick .

Took the sample along to my local machinist. No problem , close enough to 0.9 mm pitch . He'll thread up a 100 mm piece of brass at each end and i'll machine up the rest .
cheers, Steve

Can anyone post some pics of a disassembled unit please.
Many thanks George

These units are sometimes called door snubbers.
I am struggling to find any second hand female parts.
Has anyone got any pics or drawings so that I can try and make a couple?

Is John Cary still kicking in Boston ? he had a lot of such parts.
Steve

John Carey is in Ipswitch.
He is still going.
(978) 356-4745

Yep, good man .

Do you happen to have an email for the gentleman?

Feathers wrote: ↑Thu Oct 24, 2019 2:32 pm John Carey is in Ipswitch.
He is still going.
(978) 356-4745

He doesnt do email as i recall