My tire guage, let me show it to you.
I have tinted the different parts different colors. I blanked out some of the background to get the files size down.
Clockwise from the upper left:
The red thing is a male quickrelease connector for my air hose.
The blue is an adjustable air pressure regulator, adjusted for a max pressure of 15% or so LESS than the max scale on the pressure gauge, see below.
The green is a tire inflater that harbor freight had on sale for $5 or so at the springfield MA store a while back.
The yellow is a pressure guage with a maximum scale of 100 PSI.
This is not the guage that came with the inflator originally. The original gauge had a maximum scale of 250 PSI, so that the gauge needle would not peg and bend when the inflator was attached to a 249 PSI air supply by the user.
I had to remove the original gauge (the threads are glued), drill the hole for a 1/8 national pipe taper (NPT) tap, and rethread. 1/8 NPT is what my new 100 PSI gauge uses.
Now you doubtless
ask, why a 100 PSI gauge? Why not a gauge with more resolution, say a 60 PSI gauge if you are going to inflate to 44 PSI?
Because all gauges of this type (bourdon tube) are non-linear in response. You will have noticed that the scale printed on the dial face IS linear, however! Why? The customer will think the gauge is "ugly" if the scale is printed nonlinear, that is, compressed and expanded to make the gauge actually accurate. You will notice a little peg to stop the needle so it cannot go much below "zero", and you can guess why.
Get to the point, blotivating windbag, you scream at your monitor.
The gauge IS accurate near the center point of the scale. That is where it is calibrated in production. A 100 PSI gauge is accurate around the 50 PSI mark. Since I inflate to 44, I am close to the accurate area.
All the parts are surplus and hardly cost anything at all.