2” long-reach dial gauge sticking

[Guineafowl]

This type, from ARC:


Sticking repeatably at two or three points.

The rack and pinion part seems to have too much lash, so the teeth are trying to overtake each other at times. There doesn’t seem to be a way of adjusting it. The brass plate has no play for adjustment that I can find:

Return, or am I missing something?

 

[Morrisman]

Have you tried loosening the two screws and twisting a screwdriver in the gap between the plate and the case, while tightening the screws? That might move the plate the few thou needed to mesh the gear properly.

 

[Pete.]

Whenever I get a sticky dial guage plunger I give it (the plunger) a spray with brake cleaner and work it in and out a few times. Has always done the trick for me.

 

[Agroshield]

No idea, but I wonder what the regular pattern of square indentations in the brass is for. No-one would do it on the inside of an instrument just for decoration.

Could the plunger be slightly bent?

Also the tube on the top that receives the plunger could be bent or dented. It should be easy to remove that and see if it makes any difference. It may be that the plunger is not a snug fit in that tube so the point may be irrelevant

Have you tried loosening the two screws and twisting a screwdriver in the gap between the plate and the case, while tightening the screws?

The small gear that meshes with the rack is connected to the large gear below it. You would need to verify that the shaft only cantilevers off the upper brass plate and is not attached in any way to the lower speckled plate. There is a small gear in the centre of the gauge, attached to the hand. You would need to check that the big gear does not touch that.

 

[voipio]

Hard to be sure from the photo, but is there some gunk caught in the teeth of the steel gearwheel? It might be possible to ease it out with the tip of a sewing needle.

 

[Morrisman]

No idea, but I wonder what the regular pattern of square indentations in the brass is for. No-one would do it on the inside of an instrument just for decoration.

Could the plunger be slightly bent?

Also the tube on the top that receives the plunger could be bent or dented. It should be easy to remove that and see if it makes any difference. It may be that the plunger is not a snug fit in that tube so the point may be irrelevant


The small gear that meshes with the rack is connected to the large gear below it. You would need to verify that the shaft only cantilevers off the upper brass plate and is not attached in any way to the lower speckled plate. There is a small gear in the centre of the gauge, attached to the hand. You would need to check that the big gear does not touch that.

I wonder if the whole shebang can be rotated in the case, backplate and all, so the depth of engagement of that gear onto the rack is adjustable. Can’t see what screws there are securing it in the pic.

 

[Misterg]

I wonder what the regular pattern of square indentations in the brass is for. No-one would do it on the inside of an instrument just for decoration.

It is often seen on support plates inside "clockwork" type mechanisms (gauges, mechanical timers, mechanical electricity meters, etc.). I had always thought it was an artifact of some sort of leveling or stretching process to stabilise the sheets or flatten distortion from punching, etc. but I've no idea what the process actually is.

 

[voipio]

The indentations may be to work harden the brass, through the production of locally spread distortions in the metal, without significantly affecting the dimentions of the plate.

 

[Misterg]

Seems the indentations are from a process called 'stippling' (in the USA?), 'Planieren' = 'planishing' in Germany & 'waffle iron flattening' (in Japan?) and is, indeed to flatten the sheet metal parts.

Leads from here and here.

(Sorry for the off-topic)

 

[brightspark]

send em back if there new

 

[More Amps]

From the photo, it looks as if someone assembled it with a pinion gear that's too small.

 

[Agroshield]

Leads from here and here.

Thanks for doing the research. It is good to learn something.