25mm manometer advice

[Steyr]

With my gun (Huben K1) completely drained of air, the manometer needle is not at zero exactly which is not doing my OCD any good! I want to to adjust this (I know, I know, first world problems). Is there any way of removing the plastic window without cracking it, and if not are there any plastic clear window replacements in case there is no way to remove it without cracking it. Its a 25mm manometer gauge, looks pretty standard. There doesn't seem to be any sideports where I could insert a syringe and pop it off.

 

[nervoustrig]

If that apparent 1 MPA discrepancy bothers you, don’t ever check its accuracy throughout its operating range.

 

[Steyr]

its probably more like 2mpa! and it might be why many manometers are "inaccurate" as they aren't set at zero when there is no pressure in them maybe worth checking yours?

 

[douger]

25 mm sehkment digital gauges are very nice

 

[nervoustrig]

These miniature gauges are typically specified with a midrange accuracy that is pretty poor, and a full range that is very nonlinear...the latter meaning a 1 (or 2) MPa offset at the bottom end of the range is swamped out, or equally likely to skew the reading in a beneficial way in the range we care about, as it is to skew it in a detrimental way.

Or to put it more more simply, a 25mm gauge is merely a rough guess as to the actual pressure.

If you want to make the gauge more useful, I recommend indexing the scale to at a useful value like the max fill pressure or the regulator’s setpoint. Indexing the needle to the zero marking is unlikely to do anything to improve its accuracy in the range where it actually matters. How often will the gun be near zero pressure?

 

[Steyr]

yes, i do accept what you say , but if manometer is not set at zero to begin with, then theres no chance of any reading being correct.

this gauge by the way is the regulator pressure gauge, i set the huma regulator at 170bar and the reading on this gauge is185bar, so I if I can set this to zero when pressure is zero, I actually don't think it be that inaccurate.

anyways, back to original question, how to get the window off or are there any window replacements?

 

[nervoustrig]

i set the huma regulator at 170bar and the reading on this gauge is185bar

Quite a lucky break, then

And a tip of the hat for the patient and conscientious effort to interpolate such precise readings on a gauge whose 10 bar graduations are only about 0.7mm apart!

back to original question, how to get the window off or are there any window replacements?

In a couple of cases I was able to squeeze the gauge body and pop out the lens. Padded jaws on a bar clamp.

 

[dizzums]

lol .. i have a couple of times 'adjusted' a gauge that was severely torqued ...its a simple matter of carefully bending the stem over (NOT the needle) .. in the direction it needs to go to get it where you want zero ..this by no means makrs it accurate, but it will be better .. anyway yeah, use a very sharp tiny drill bit by hand dead center to access it, and the same bit to bend your stem over..patch it with an ultra cool micro sticker from a sheet of some kind of model your into ..
*note - the most accuracy will be achieved with stem end centered in the hole of the dial, see how yours is 'high' ..so bend in the direction to center it to achieve zero ..

 

[Steyr]

i'm betting that the circular white disc with the calibrations is not fixed and will rotate, so wouldn't have to mess with the needle. So lining up the disc with the needle at dead zero will help with accuracy (of course limited by how inaccurate these things are).

 

[ChuckHunter]

yes, i do accept what you say , but if manometer is not set at zero to begin with, then theres no chance of any reading being correct.

this gauge by the way is the regulator pressure gauge, i set the huma regulator at 170bar and the reading on this gauge is185bar, so I if I can set this to zero when pressure is zero, I actually don't think it be that inaccurate.

anyways, back to original question, how to get the window off or are there any window replacements?

Set to 170 using what? The marks on reg are just a reference and not accurate either!
Unless you have an actual reg tester with a big accurate gauge you never going to know the actual pressure!

 

[DesertSilver]

That's what I was wondering. I had assumed (not a good thing to do) that he has a huma reg tester and that's where he got the reading.

 

[Steyr]

i would assume that the marks on the huma reg are fairly accurate, to say +/- 5-10 bar, i mean thats what we are paying a premium for - an easily adjustable reg with markings.