1911 brass radiator drain plug size
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Topic author - Posts: 589
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1911 brass radiator drain plug size
I picked up a decent 1911 Brass radiator just before Hershey. I would like to test it out, but do not know ow the correct thread count and 'bolt' size which would fit in the drain hole where the petcock would go. Is anyone aware of what the size of those petcock threads might be? Thank you in advance. ** Updated with photos **
Last edited by Retro54 on Wed Oct 11, 2023 9:10 pm, edited 1 time in total.
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Re: 1911 brass radiator drain plug size
It is not a bolt, it is pipe thread. Should be 1/8" NPT.
I know the voices aren't real but damn they have some good ideas!
1925 Cut down pickup
1948 Ford F2 pickup

1925 Cut down pickup
1948 Ford F2 pickup
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Re: 1911 brass radiator drain plug size
What Mark G said!
FYI. It is however close to a standard bolt thread, a 3/8 - 24 if I recall correctly. Sometimes, if the tapered pipe thread has been overtightened a bit much, the bolt thread can be started in the hole. Do not do that except in an emergency (like in the middle of nowhere and the petcock fell out back there somewhere), as forcing the bolt into the tapered pipe thread will quickly destroy it.
FYI. It is however close to a standard bolt thread, a 3/8 - 24 if I recall correctly. Sometimes, if the tapered pipe thread has been overtightened a bit much, the bolt thread can be started in the hole. Do not do that except in an emergency (like in the middle of nowhere and the petcock fell out back there somewhere), as forcing the bolt into the tapered pipe thread will quickly destroy it.
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Re: 1911 brass radiator drain plug size
Use a wood dowel, sharpen the end slightly. Then screw it in place. Won't damage the threads.
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Re: 1911 brass radiator drain plug size
Jack Putnam, in Ohio wrote: ↑Wed Oct 11, 2023 8:24 pmUse a wood dowel, sharpen the end slightly. Then screw it in place. Won't damage the threads.
Excellent idea, I appreciate the assistance. I just want to seal it up to check for leaks.
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Topic author - Posts: 589
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Re: 1911 brass radiator drain plug size
Of course. I was searching for the right term, but you understood what I was looking for anyways. Thank you.Mark Gregush wrote: ↑Wed Oct 11, 2023 7:16 pmIt is not a bolt, it is pipe thread. Should be 1/8" NPT.
Andy
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Re: 1911 brass radiator drain plug size
Just screw a petcock in!
Allan from down under.
Allan from down under.
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Re: 1911 brass radiator drain plug size
Sorry Andrew. Over 50 years of me collecting T parts means I have ample spares. If it is of any use, you could temporarily screw in the top oil petcock from any T to do your leak test.
Allan from down under.
Allan from down under.
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Re: 1911 brass radiator drain plug size
We all know Henry liked to save dollars and cents whenever he could, seems it took a while on the Pet cocks, the radiator one was part No 3940 with the parts book changing to order and use the fuel tank one 2908 then finally using the oil pan 3079 Pet cock for tank and radiator as well.