What's new
What's new

Mitutoyo 192-656 height gage - adjustment/calibration question

dandrummerman21

Stainless
Joined
Feb 5, 2008
Location
MI, USA
We've got an older mit digital height gage, 192-656 0-18" that is off .004" every 6 inches. so at the full height it is about .012" off. It is consistantly off (3 inches is .002, 9 inches is .006, etc).


Putting the beams up to a large cylinder square, its pretty good (didn't measure it, but there is almost no gap the whole height of the cylinder, 10 inches). The rack is also clean. So it seems like its an encoder issue maybe?

Anyway, we've been dealing with it (our stuff doesn't usually require sub .001 measurements over long ranges, and if it did, we set up a gage block stack). But today, I took the front cover off to clean under the keypad that was sticking.

I noticed 5 potentiometers on the circuit board labeled vr1-vr5. It is a long shot, i'm sure, but do these have anything to do with calibrating this thing? I don't want to move them around if they aren't related to that.

Beyond that, is there anything I should look at while its apart, on the encoder? It looks fine, no damage as far as I can tell.
 
as I've said before, the gage is calibrated by adjusting the squareness of the beams. Checking them against a cylinder square doesn't mean jack shit.
Don't fuck with the encoder, it's not the problem and you'll just be driving down the road to buying a new height gage.
When you say it's an older height gage that you got, that means you bought the piece of shit off ebay, am I right? $50 says it's been dropped. Adjust the beams and it should be good to go.
 
as I've said before, the gage is calibrated by adjusting the squareness of the beams. Checking them against a cylinder square doesn't mean jack shit.
Don't fuck with the encoder, it's not the problem and you'll just be driving down the road to buying a new height gage.
When you say it's an older height gage that you got, that means you bought the piece of shit off ebay, am I right? $50 says it's been dropped. Adjust the beams and it should be good to go.

Was bought at local auction some years ago (about 5). Definitely a fraction of new.

It had a calibration sticker, but who knows how well (if at all) it was calibrated then.


I agree, squareness of the beams should be the only thing I concern myself with. Just to check now, using feeler gages on the main (front) beam, I only see .001 difference over about 15" checking against a bigger cylinder square. Why do you say checking against a cylinder square doesn't mean shit? What else would I check it against?

Would I intentionally tilt the beams to get it to read correctly? .004" over 6" is A LOT, it reads 5.996 on a 6" gage stack. The amount of tilt to get it to read right would be insane...

I also don't see anything to adjust. Appears to be pressed (glued?) into the base. There is some sort of cover at the top I can't get off either.
 
Would I intentionally tilt the beams to get it to read correctly? .004" over 6" is A LOT, it reads 5.996 on a 6" gage stack. The amount of tilt to get it to read right would be insane...

That is exactly right. The amount you need to "tilt" it is extremely small. It's not a function of the angle of the beams. That would be an insane amount. It's hard to describe, but once you've done it, it will make sense.
 
That is exactly right. The amount you need to "tilt" it is extremely small. It's not a function of the angle of the beams. That would be an insane amount. It's hard to describe, but once you've done it, it will make sense.

You are right and wrong with that post....


You're right about one thing, that fixed it. I found the little set screws at the top (how didn't i see those before??), loosened up the front post's screws, and tapped on the front post downward. It went from 5.996" reading to 6.002". So I hit the rear post down a little. now I've got it reading 6.000 on a gage block stack, I even put another 3" on it and it read 9.0005" which is plenty good enough for me.


But you're wrong about "it will make sense". Still trying to wrap my head around it...
 
The encoder is off, most of those boards are less than 50 bucks, I have changed them before and they take care of the error. easier than even thinking of reprogramming
 








 
Back
Top