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Detroit radiator valves and steel rivet radiators

tim smith
tim smith Member Posts: 2,363
Anyone out there had a problem with the spud on an old Detroit radiator valve being a little smaller than current size spud on radiators valves. We have an 1-1/4 valve that the new spud will not fit in the tap on bushing on radiator. Either will std nipple. The old spud spins right in 2 to 3 turns. Can even get a 1/2 thread with new valve to start?? Threads are clean. Any thoughts appreciated.


  • mattmia2
    mattmia2 Member Posts: 3,168
    Pictures of the radiator? Perhaps there is a bushing in the radiator with some oddball or obsolete thread. There was a very old standard for fine thread pipe taper.
  • tim smith
    tim smith Member Posts: 2,363
    the threads match up but does look like more taper on old than new.
  • mattmia2
    mattmia2 Member Posts: 3,168
    Are you positive the pitch is the same? Do they mesh exactly if you hold the old and new spud next to each other? The new spud could be out of tolerance. If you are positive they are the same pitch you could cut one side or the other deeper with a tap or die.
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