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Mitutoyo 92 series Height Gage 18"

joesimmers

Aluminum
Joined
Jan 14, 2007
Location
Bellville, Ohio
I have a rather new height gage and when I crank the wheel DOWN it is super smooth and quiet. However when I crank UP there is a "clicking noise" and I can also feel some resistance but not much, mainly it the clicking noise driving me crazy, anyone else had this??

Thanks, Joe
 
Any chance that the handwheel is loose enough that when you crank upward the fine adjust knob is hitting the geared wheel behind the handwheel?
 
Joe,

I went to check my books for a "92" series height gage and only found "192". Is your a dual beam and is it digital or dial?

If it is a dual beam style, check one more thing. Put an indicator on the end and run it up and down against something you know is square to the plate. (I know you aren't supposed to use these to check square, but the info is needed to answer the question).

The dual beams use a rotary encoder type thing with 2 gears that ride inside the front beam against the finer rack. The bottom gear translates the vertical movement into rotary motion while the top gear kind of takes up the slack with a coil spring. If your height gage got dropped or violently set down or just handled incorrectly by squeezing the paralell bars together while carrying it around, the perp to the base may be off enough that the top gear is not fully engaging the rack on the upward movement. I have seen this more than once here at work. We have >60 Mit height gages in the plant.

Of course if your 92 series isn't dual beam, forget it. I wish I could locate my CD ROM with the parts breakdown but apparently day shift cleaned up and hid it from me. -Mike
 
Holescreek, It is a 192-671 to be exact. Were you able to fix yours when they had this problem or were they sent in for repair?

Mine is a dual beam digital model.

Thanks, joe
 
I just ran it up and down with a .0001 indicator against an 8" angle plate, it appears to be within .001 total on 8" verticle. And I do not feel any "tight spots" anywhere along the entire travel of the gage.

Thanks, joe
 
Joe,

I do all of the repair work on the gages at work and here in my home shop. Having so many gages at work it's a sure bet that a couple get destroyed, providing me with plenty of spare parts for the rest. Mitutoyo supplies 99% of our variable gages. Last time I checked repair shops wanted $60 just to look at a height gage.

Since the tick is not normal you can try a couple of things to isolate it.

Remove the handwheel and the 3 screws that hold the gear wheel for the fine adjust on. Remove it all and pull out the handwheel shaft. Move the body up and down and see if it ticks. If it doesn't, the handwheel shaft teeth are damaged and it will need replaced. They wear out quite often.

If it still ticks, remove the two screws on the handwheel side of the body and the two screws on the back to remove the readout/control side of the body. You will be able to see the large flat spring that keeps pressure on the front beam and the encoder assembly just to the right of it. Make sure the 3 screws that hold the encoder to the body are tight. Slide the unit up and down and check for ticks.

Do not remove any of the encoder screws until you know which 3 hold the encoder in place and which 2 hold the encoder together! :willy_nilly:

Post your progress so far before you get deeper into it. Hopefully it is just the teeth on the handwheel shaft. -Mike
 
Hello Mike, thanks for your help. Your directions are fantastic!

I ended up removing the encoder assembly, it all looked good so I
reassembled it. The tick went away!!!!

Now it rides up and down smooth but i noticed there is .004 to .006 of backlash in
the unit, I am sure this is because when reinstalled the encoder assembly I was not
able to put tension on the round spring.

Any chance you might know the secret to this?

Also if you have some spare parts is there any chance you might have a carbide scriber tip I could purchase? I am in real need of one of these to get me going.

Thanks so much for your help.

Joe Simmers
 
Joe,

You are almost done with the repair! I was saving the encoder stuff for the next installment but you beat me to it. There is no need to pretension the top gear, the spring will do it for you. However, when you reinstalled the encoder you'll have noticed a little slop in the screw holes that the 3 screws go through. It is important to put just a little leftward tension on the encoder so the gears mesh with the rack while you tighten the screws. This is probably why you have noticed the backlash.

Good news and bad news. Good news is that the tick is gone. bad news is that you now have to calibrate the height gage since you removed the encoder. Good news is that it's relatively easy to do. Bad news is that calibration places don't want you to know that.

Gather up some gage blocks, paper and a pencil. Set your indicator back up on the end and zero everything on the lowest block. Check your digital readings against the block stacks all the way up. I'm guessing that it will be off a bit based on your .001" reading on the angle plate, if the angle plate was a good one.

There is a block at the top of the two columns with 2 set screws on each column. If your readings on the gage blocks grows over the range loosen the two setscews on the rear column and use a block of soft wood or hammer handle and give the block a tap foreward. If your readings are low over the range tap the block backwards. Then re-tighten the setscrews and retest against the blocks. There is one other adjustment but you shouldn't have to mess with it and it'd take too long to type. Let us know what you find. :cheers: -Mike
 








 
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