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+--- Thread: Smiths MA Speedo - fixing nut thread? (/showthread.php?tid=9491)
Smiths MA Speedo - fixing nut thread? - Chris KC - 28-07-2024
Self explanatory I hope - hoping to fit an MA speedo but one nut is missing - anyone know what thread it is?
M4 perhaps?
I've exhausted the odds & sods box and found nothing which will go on properly; Google likewise unhelpful.
RE: Smiths MA Speedo - fixing nut thread? - Robert Leigh - 28-07-2024
Looks like 4BA to me.
RE: Smiths MA Speedo - fixing nut thread? - Chris KC - 28-07-2024
Thanks Robert.
I did confirm that is isn't M4 - haven't any 4BA's to try but at least now I know what to look for - Google awaits...
RE: Smiths MA Speedo - fixing nut thread? - Chris KC - 05-08-2024
Just thought I'd leave the result here for anyone who comes looking later...
Ordered some 4BA brass terminal nuts which are beautiful - but too small.
Tried 5/32 BSW, about the right size but the pitch was wrong.
Got out an even bigger magnifying glass and my best eyes, and re-counted the threads - 3BA?
Arrived this morning and they fit!
The ones I bought are light aluminium and don't seem very robust or pretty.
I think I just might acquire a 3BA tap and run it through those lovely 4BA brass terminal nuts.
RE: Smiths MA Speedo - fixing nut thread? - Jeff Taylor - 05-08-2024
3BA Full Brass Nuts but not terminal nuts are available here:
https://www.ba-bolts.co.uk/brassnut.html
RE: Smiths MA Speedo - fixing nut thread? - Chris KC - 05-08-2024
Thanks Jeff but I rather like the knurly ones.
RE: Smiths MA Speedo - fixing nut thread? - Robert Leigh - 06-08-2024
Sorry I got the BA size wrong; I'm a bit rusty on BA having not used it since the sixties.
RE: Smiths MA Speedo - fixing nut thread? - Chris KC - 06-08-2024
No problem Robert, as always any help is appreciated.
I do better on the bigger threads but I struggle to count tpi these days when it's 30+!