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1911 brass radiator drain plug size
Posted: Wed Oct 11, 2023 7:07 pm
by Retro54
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 **
Re: 1911 brass radiator drain plug size
Posted: Wed Oct 11, 2023 7:16 pm
by Mark Gregush
It is not a bolt, it is pipe thread. Should be 1/8" NPT.
Re: 1911 brass radiator drain plug size
Posted: Wed Oct 11, 2023 8:10 pm
by Wayne Sheldon
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.
Re: 1911 brass radiator drain plug size
Posted: Wed Oct 11, 2023 8:24 pm
by Jack Putnam, in Ohio
Use a wood dowel, sharpen the end slightly. Then screw it in place. Won't damage the threads.
Re: 1911 brass radiator drain plug size
Posted: Wed Oct 11, 2023 8:27 pm
by Retro54
Jack Putnam, in Ohio wrote: ↑Wed Oct 11, 2023 8:24 pm
Use 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.
Re: 1911 brass radiator drain plug size
Posted: Wed Oct 11, 2023 8:28 pm
by Retro54
Mark Gregush wrote: ↑Wed Oct 11, 2023 7:16 pm
It is not a bolt, it is pipe thread. Should be 1/8" NPT.
Of course. I was searching for the right term, but you understood what I was looking for anyways. Thank you.
Andy
Re: 1911 brass radiator drain plug size
Posted: Thu Oct 12, 2023 2:39 am
by Allan
Just screw a petcock in!
Allan from down under.
Re: 1911 brass radiator drain plug size
Posted: Thu Oct 12, 2023 5:26 am
by Retro54
Allan wrote: ↑Thu Oct 12, 2023 2:39 am
Just screw a petcock in!
Allan from down under.
Very easy to say if you have one! I do not have any spare sitting around and am not about to purchase one just to test it out.
Re: 1911 brass radiator drain plug size
Posted: Thu Oct 12, 2023 5:36 am
by Allan
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.
Re: 1911 brass radiator drain plug size
Posted: Thu Oct 12, 2023 7:17 am
by Kerry
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.