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+--- Thread: 1/2 BSP on Austin 7? (/showthread.php?tid=6940)
1/2 BSP on Austin 7? - JonE - 06-12-2021
I bought a tap and on looking again at the Cornwall club threads list, can't now remember why I have it! Can someone enlighten me so I can add a note to it please.
RE: 1/2 BSP on Austin 7? - Ilmoro - 06-12-2021
Is it to modify a stripped gearbox drain plug thread?
RE: 1/2 BSP on Austin 7? - JonE - 06-12-2021
that's the forum thread I found too! But no, I dont think I'd have bothered... which is why I'm head scratching again.
RE: 1/2 BSP on Austin 7? - Howard Wright - 06-12-2021
Cancel that….. the king pin brass disc is 3/4” 20TPI
Hi Jon
Working from memory I have a feeling that the thread at the top of the king pin shaft that takes the brass closing disc is 1/2” BSP.
Do check with a thread gauge before you go tapping it. The tap should be an end tap rather than a taper tap too.
I also think the filler plug on a 31 back axle could be the same thread but I’m not sure.
Cheers
Howard
RE: 1/2 BSP on Austin 7? - JonE - 06-12-2021
I wonder if I had the same thinking as you, Howard i.e. I read something wrong and bought it.
Funnily enough, I have just been playing with the brass discs and wondering about their thread. I have little offcuts from my cross tube which is the same thread, and thought I could make some recycled plugs for the king pins, perhaps adding an allen key connector.
RE: 1/2 BSP on Austin 7? - Andy Bennett - 07-12-2021
Were you doing some plumbing at the time, minds can wander?
RE: 1/2 BSP on Austin 7? - Howard Wright - 09-12-2021
Hi Jon
I think the sump drain plug is 3/4” diameter and 14 tpi. Which is, I believe, 1/2” BSP.
Cheers
Howard
RE: 1/2 BSP on Austin 7? - dickie65 - 09-12-2021
The drain plugs are a parallel thread so it would be BSPP Not BSPT
That is if in fact they are BSPP !
RE: 1/2 BSP on Austin 7? - Hedd_Jones - 09-12-2021
They are neither. They are 3/4 diameter 14TPI whit threadform.
A parallel 1/2 BSP tap, would clean the thread out nice, but the whole kaboodle would be bigger requiring a new plug.
I've got a lot of 14tpi whitform threads on my steam roller, which is 1920. It is alledged that the 14tpi tooling was to some Great War ministry naval standard. I expect probably why Austin also had it.
I've had to beg, borrow and make tooling to suit when carrying out repairs.
RE: 1/2 BSP on Austin 7? - dickie65 - 09-12-2021
Hedd.
My thoughts were that the drain plugs are a 3/4 Whitworth form so thanks for confirming it.