petrol tap thread size

[huddie]

Hi All,  Just about to start the paint job on my 1957 Gold Flash. I have removed the petrol tank taps, as my first job on the tank before I paint it is to stabilise the internal rust and then use a tank sealant. I cannot identify what thread it is! It appears to be 20 threads per inch and the diameter of the threads is greater than 5/8ths, the mic readout gives 0.65 in.! Can any of you help. I just want to cut two bolts to seal the tap holes as the inhibitor has the consistency of water and therefore needs a good seal.
Regards Huddie.
(ps If you read this one Nitti, the badges are great, thanks)

[bsa- bill]

I believe the taps are 1/4 inch gas thread but there is an adapter in between tank and tap ( at least on my 61 flash )
Sorry no idea about adaptor size but they are readily available from usual suppliers.
Not much help I'm afraid but someone will have more info for you.
I'm about to do the same to the tank for my project ( and it's a new tank )

All the best - Bill

[huddie]

Thanks Bill, the riddle is now solved, thanks to a retired plumber who lives just up the road. He took my petrol tap saying he had loads of taps and dies in his shed. He came back an hour later with a die that was dead right. It is 3/8 pipe (British Sandard Pipe). So there you have it.
Regards Huddie

[LJ.]

Just in case anyone is looking for new petrol taps (UK) there is a couple of excellent Links to suppliers of such...

http://www.vintagecarparts.co.uk/en/list+taps,+pipe+and+fittings~taps~in+line/

http://www.vintagebike.co.uk/Spares/Fuel/Taps/Fuel.htm

[manosound]

Does the inhibitor set hard? If so, and it starts out watery, could you risk gluing the plugs in place? My recollecton when, plasticising the inside of my tank, was using plumbers' putty, but the plasticisor was thick and definity set up hard.

Richard L.

[huddie]

Hi richard   Yes, my plugs were a bit short so the resin set over the top and down into the thread hole a bit. Very careful leverage on the plugs got them out without damaging the sealant. I then drilled out the two holes finally using a 19/32" drill and retapped the hole including the thickness of the resin using a 3/8" bsp tap.
Regards Huddie