Author Topic: Nut and Bolt sizes on T/S6 motors  (Read 4076 times)

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Offline kmd

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Nut and Bolt sizes on T/S6 motors
« on: 11 Aug 2008 at 15:13 »
Hi All

Can any help me with the sizes of the nuts and bolts on the T/S6 Engine?
I think they are 25tpi but they seem to come out really odd sizes,
Good old Mr Douglas?

Many Thanks
Kevin

Offline Chris

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Re: Nut and Bolt sizes on T/S6 motors
« Reply #1 on: 11 Aug 2008 at 18:41 »
Hi Kevin
    The most common bolt size on the 1930s models relating to cylinder head nuts and studs etc. is the 5/16" x 25tpi. There are also examples of the other Douglas special thread size of 17/64" x 25tpi. Taps and dies for these sizes are held in pre-1939 Spares by the LDMCC. You may also find examples of 1/8" and 1/4" BSP and another odd size used on oil and petrol unions being 7/16" x 19tpi. The carburettor base connection on many carburettors is 9/16" x 20tpi. Some timing cover screws are 3/16" x 27tpi. Again taps are kept by LDMCC for this size. Even where standard Whitworth threads are used Douglas often selected the non approved sizes such as 7/32" x 24tpi screws  used on many pre-1939 flat tank models for holding the petrol tank to the top tube. I am sure it was all part of Mr Douglas' plan to ensure that if you wanted spares for your Douglas, even down to a nut, you had to buy them from him.
Chris.

Offline kmd

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Re: Nut and Bolt sizes on T/S6 motors
« Reply #2 on: 12 Aug 2008 at 08:57 »
Chris

Thats a great help.
 
Thanks
Kevin

 

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