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Author Topic: Petrol tank screws  (Read 4236 times)

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Offline usa23/4

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Petrol tank screws
« on: 30 Dec 2009 at 23:07 »
Hi - Does any one know where I could obtain a set of pan headed screws -  Whitworth 7/32” x 24 tpi - (according to Chris's very helpful post in 2006 regarding screw sizes) - for securing the petrol tank on my 1923 2 3/4 TS model?
Any information would be appreciated.  Thanks Tim
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Offline Chris

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Re: Petrol tank screws
« Reply #1 on: 31 Dec 2009 at 07:40 »
Hi Tim
     The correct screws for the petrol tank support are instrument head, not panhead. That is they are countersunk under the head but with a slight dome on top. They are not kept in LDMCC spares so have to be made by anyone with a small lathe. A reason why we have never taken them into stock is that over the years many tanks have had the threads stripped or crossed and as a result tapped out oversize. 1/4" BSF is most common but I have even seen them tapped out to the Douglas special thread 17/64" x 25tpi. The 7/32" x 24tpi is a standard Whitworth thread so dies are readily available to make it easier to thread the screws in a lathe as opposed to screw cutting. Chris.
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Offline usa23/4

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Re: Petrol tank screws
« Reply #2 on: 02 Jan 2010 at 14:32 »
Quote from: Chris on 31 Dec 2009 at 07:40
Hi Tim
     The correct screws for the petrol tank support are instrument head, not panhead. That is they are countersunk under the head but with a slight dome on top. They are not kept in LDMCC spares so have to be made by anyone with a small lathe. A reason why we have never taken them into stock is that over the years many tanks have had the threads stripped or crossed and as a result tapped out oversize. 1/4" BSF is most common but I have even seen them tapped out to the Douglas special thread 17/64" x 25tpi. The 7/32" x 24tpi is a standard Whitworth thread so dies are readily available to make it easier to thread the screws in a lathe as opposed to screw cutting. Chris.

Hi Chris,
Thank you for your reply and information - I am in the USA at present and I am not aware of any local sources around here that would be interested in producing a small quantity of screws.
Could you recommend anyone in the UK?  - that would be interested in doing the job - I do have a UK mailing address.
Thank you again for your help.
Cheers, Tim

« Last Edit: 06 Jan 2010 at 19:46 by Dave »
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