Radiator petcock

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Topic author
Gary
Posts: 4
Joined: Sat Dec 26, 2020 5:08 pm
First Name: Gary
Last Name: Cryer
* REQUIRED* Type and Year of Model Ts owned: 1923 Model T Roadster
Location: Wichita Kansas
MTFCA Number: 21445

Radiator petcock

Post by Gary » Sat Dec 26, 2020 5:32 pm

I purchased a new Brassworks radiator for the 23 Roadster, I attempted to use the old petcock from the old radiator but it was a bit to big for the new threaded hole, so ordered a new petcock from Lang's and it also is to large for the threaded hole. Has anyone else had this problem and if so have a solution.

User avatar

CudaMan
Posts: 2385
Joined: Fri Jan 04, 2019 4:17 pm
First Name: Mark
Last Name: Strange
* REQUIRED* Type and Year of Model Ts owned: 1924 Cut Off Touring (now a pickup)
Location: Hillsboro, MO
MTFCA Number: 30944
MTFCI Number: 23667
Board Member Since: 2013

Re: Radiator petcock

Post by CudaMan » Sat Dec 26, 2020 6:56 pm

Get a 1/8 inch pipe tap and tap the hole a bit further. Sneak up on it so that you don't go too far.

Another tip - put some grease in the flutes of the tap to catch the chips and keep them from falling into the radiator or onto the floor. :)
Mark Strange
Hillsboro, MO
1924 Cut-off Touring (now a pickup)


Topic author
Gary
Posts: 4
Joined: Sat Dec 26, 2020 5:08 pm
First Name: Gary
Last Name: Cryer
* REQUIRED* Type and Year of Model Ts owned: 1923 Model T Roadster
Location: Wichita Kansas
MTFCA Number: 21445

Re: Radiator petcock

Post by Gary » Sun Dec 27, 2020 7:43 am

CudaMan wrote:
Sat Dec 26, 2020 6:56 pm
Get a 1/8 inch pipe tap and tap the hole a bit further. Sneak up on it so that you don't go too far.

Another tip - put some grease in the flutes of the tap to catch the chips and keep them from falling into the radiator or onto the floor. :)


Topic author
Gary
Posts: 4
Joined: Sat Dec 26, 2020 5:08 pm
First Name: Gary
Last Name: Cryer
* REQUIRED* Type and Year of Model Ts owned: 1923 Model T Roadster
Location: Wichita Kansas
MTFCA Number: 21445

Re: Radiator petcock

Post by Gary » Sun Dec 27, 2020 8:09 am

Thanks I was thinking that might be what I need to do. Do you happen to know the threads per inch on those fittings?

User avatar

CudaMan
Posts: 2385
Joined: Fri Jan 04, 2019 4:17 pm
First Name: Mark
Last Name: Strange
* REQUIRED* Type and Year of Model Ts owned: 1924 Cut Off Touring (now a pickup)
Location: Hillsboro, MO
MTFCA Number: 30944
MTFCI Number: 23667
Board Member Since: 2013

Re: Radiator petcock

Post by CudaMan » Sun Dec 27, 2020 8:33 am

The thread pitch is 28 tpi, it's part of the standard for 1/8 pipe. A regular 28tpi tap won't work, regular taps are designed to cut straight sided holes. The pipe tap has a special taper shape so that the threads get tighter as you screw the fitting in, that's why you don't want to cut too deep.
Mark Strange
Hillsboro, MO
1924 Cut-off Touring (now a pickup)


Topic author
Gary
Posts: 4
Joined: Sat Dec 26, 2020 5:08 pm
First Name: Gary
Last Name: Cryer
* REQUIRED* Type and Year of Model Ts owned: 1923 Model T Roadster
Location: Wichita Kansas
MTFCA Number: 21445

Re: Radiator petcock

Post by Gary » Sun Dec 27, 2020 8:53 am

Ok thank you for all this information, I understand about the tapering of the pipe tap now.

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