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I have a pressure gauge which threads onto a hose bib. I am trying to have the pressure gauge end up facing upwards in a readable position. Every time I try to start the thread at a different position such that the number of turns would have the readable face of the pressure gauge in the correct orientation it finishes at the exact same place.

Is the problem that the male thread will always start thread at the exact same spot on the female threaded piece?

I've managed to spin the hose bib such that the pressure gauge is in the correct position but I have two manifold shutoffs that have temperature gauges which are in a similar state and since I didn't have much luck with the hose bib I worry I won't be able to adjust their orientation.

manifold shutoff with upside down temperature gauge

The only piece I am looking to change the orientation of is the temperature well. It does seem to have two nuts on the back so hopefully it does spin independently of the thread orientation.

temperature well

Fresh Codemonger
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3 Answers3

15

Are you actually having to twiddle the gauge onto the thread, hoping that by the time it's tight it will be facing the right way? That just sounds all wrong. You ought to be able to hold the gauge steady until the thread is almost tight, then twist it back approximating the last few degrees it will spin as the nut nips up. [Sometimes a little trial & error for a perfect result.] The thread otherwise always not only starts, but will tighten up in the same place. This not a sensible manufacturing method for something that must face an unknown yet specific direction.

This nut must be able to tighten independently of the gauge's orientation. You should be able to hold the gauge approximately stationary as you tighten up this nut.

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Tetsujin
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If the female and male threads are not adjustable (the cutting method has been explained, but I don’t like that) then I use ptfe and tighten until it is both sufficiently tight and positioned correctly.

Or, since all you need is to notice a difference between the actual reading and what is required you can put a mark on the gauge glass.

Solar Mike
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A pressure gauge can't use a thermowell, so the things with thermowells are just thermometers. In that case, the threads from thermometer to thermowell just keep the thermometer from falling out, and don't even need to be tight, as the fluid seal is made by the thermowell and its o-ring in its hole.

Ecnerwal
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