Mitutoyo 12” 505-645-50 12

[PT Doc]

I have a vintage Mitutoyo 12” dial caliper that came in a wooden box. My father passed down his 6” Mitutoyo dial caliper that he used regularly as a mechanical engineer. The issue with the 12” caliper is that the small shim tool that is used to adjust the location of the dial only allows the dial to be set either at 0 or 25 or 50 or 75. 0 is 2 thou to the left of 12 o’clock. On the 6 inch Mitutoyo, adjusting the 0 to be at 12 o’clock was easy. This 12” will allow you to place the needle anywhere you want with the same resetting process when the caliper is closed, but as soon as you use the roller to open the jaws, it jumps to the closest 25 thou increment. Any thoughts on getting this to adjust to 0 at 12 o’clock. Thanks in advance.

 

[mmcmdl]

You're jumping a tooth . I have a 12" Mit that does the same thing and not sure why just yet .

Edit . Just checked my numbers . 505-628 50

 

[mmcmdl]

Another edit . Mine jumps .020 , not .025 .

 

[benmychree]

As long as the needle stays in the same position, and the dial is zeroed, what difference does it make?

 

[mmcmdl]

Yeah John , the OPs post was unclear as to whether he couldn't set the dial at 12 o'clock or the needle was jumping . In my case , I'm loosing .020 every time I open them up and re-close them . These are brand new ( 30 yo ) not used verniers . I guess you realize why they aren't used .

 

[PT Doc]

Yeah John , the OPs post was unclear as to whether he couldn't set the dial at 12 o'clock or the needle was jumping . In my case , I'm loosing .020 every time I open them up and re-close them . These are brand new ( 30 yo ) not used verniers . I guess you realize why they aren't used .

The closest to 12 o’clock that I can get my needle is 2 thou left of 12 o’clock. I can obviously move the dial and align the needle and zero. It does repeat to zero and is accurate and consistent when measuring my Mitutoyo standards 1” thru 6”.

 

[PT Doc]

As long as the needle stays in the same position, and the dial is zeroed, what difference does it make?

Yes this works. But this caliper should be able to be zerod at any position and it’s not holding the position I want it at. That was my question. I know what your saying. But if my car check engine light comes on, but still runs well, I generally look into it.