Dial test indicators upside down

[digiex-chris]

Hi Chris;

There are actually different issues here. You mention that one gage you have disengages a gear when turned upside down, I would consider that gage broken. It certainly would be unreliable even in the normal position.

Right, I've since confirmed that my Compac 244A that has the gear disengaging is infact broken. It shouldn't be doing that. It's missing a spacer. That's why I didn't test with that one. Doesn't matter though since I was wrong and that whole style of indicator is unaffected by this issue anyway. Only the type that has the long plunger that drives a pinion via a rack attached to the plunger seems possibly affected, but may not be as much of a problem for most people. I certainly haven't run into it because I tend to wind in a hundred thou or so before setting zero, which seems to be more than enough spring preload for either of the indicators in my test post. Limiting travel by .100 preload caused them to repeat perfectly every time.

I'm going to have to go visit some people and try out their good condition brand name indicators. It surprised me that both showed as good on 3 of 4 positions, and both showed strange behaviour upside down.

 

[10K Pete]

I have to admit that my own use of any kind of indicator has always, for some reason,
included a 'tension check' of the gauge spindle! I must assume that some little
neuron decided that's the way to do it.

Soooo, the reason I have never had a problem was I always had plenty of tension established!! I'm not sure I was even aware of the gravity issue on a concious level!!

Cool stuff guys, I love this site.

Pete