Radius arm thread

[David Cochrane]

Good to see my memory is not all gone to pot David - can you answer the question about Whitworth form for me please?

Stuart has given a very comprehensive & erudite answer! I always understood that the 'admiralty' threads had a Whitworth tooth form, but I am willing to be corrected.

[Ruairidh Dunford]

Thanks Stuart, very helpful - I got myself into a right fankle there!

Alastair - looks like had found exactly what you needed, not as rare as I'd believed!

[Ruairidh Dunford]

Thanks as well David.

[Alastair]

Thanks everyone! I'll be in touch David.
Has anyone ever compiled a list of all the various threads used on the 7?

Alastair

[Ruairidh Dunford]

Your Club site has the details here Alastair: http://www.austin7.org/Data%20Pages/Tech%20Data/

[Alastair]

Hanging head in shame! Our local group the Unstoppables, awarded me the annual Pratt trophy (a somewhat less than concours Pratts can, suitably mounted) at our pre-Christmas do the other day for transgressions during the past year, and this is further justification... It was the third year running and I must further admit I nominated myself this time, having gone to the wrong pub for the do.
At least we've resolved the die problem!
Thanks again everyone,.
Alastair

[Austin in the Shed]

For the radius arm threads,and others on the car it might be worth investing in a BSW/BSF thread restoring file.Cromwell tools for example sell one to clean up  8 different pitch internal and external threads for £21.Usually the radius arm threads get bruised when knocking them out of the axle and with a thread file its easier to pick up/dress the damage than trying to get a die to start and stay in pitch when threading.

[Amilcar John]

I used a thread restoring file by Sykes Pickavant from ebay - which probably means I have a more casual approach to thread form etc. 

Does that make me a bad person?

[David Cochrane]

I used a thread restoring file by Sykes Pickavant from ebay - which probably means I have a more casual approach to thread form etc. 

Does that make me a bad person?

Personally I think that you would be a better person if you'd got one from me  
(BT940 here)

[Dennis Nicholas]

According to Newnes Engineer's Reference Book (sixth edition 1954)

Admiralty fine thread (Obsolete)   Whitworth Form)  5/8 is 20 Tpi. 


British Standard Whitworth 55 degree angle 5/8 is 11 Tpi. (Whitworth form threads).

British Standard Fine 55 degree 5/8 is 14 Tpi. (Whitworth form threads)

So it seems we have established that the Herbert Austin threads were 5/8 16 Tpi (with a Whitworth 55 degree form ???)(that is with rounded tops and bottoms to the threads).

BSW, BSF and now Perhaps we could have HAT (Herbert Austin Thread)