Dial Calliper Adjustment?

[Chris CrewParticipant @chriscrew66644]

I recently bought a used Mitutoyo dial calliper gauge from a well known online auction site. It appears to be very accurate but the needle does not come to rest in the vertical position when it is fully closed. This may be the normal state of things, but having never owned this type of calliper before I don’t know. Obviously the bezel can be set at 0 to match the needle so it does not affect the operation in any way but I was wondering if it is possible to make an adjustment so that the 0 starts from the vertical position. There is no obvious way to adjust it, so is this possible or would it be better to leave well alone?

[Grindstone CowboyParticipant @grindstonecowboy]

If it was mine, I’d leave well alone (slowly learning “If it ain’t broke, don’t fix it”), but someone with the necessary skills could probably pull the pointer off and re-position it in a more pleasing position.

Or possibly the gear on the back could be disengaged from the rack to achieve the desired effect, but again, I wouldn’t.

Rob

[Michael GilliganParticipant @michaelgilligan61133]

Short of removing and repositioning the pointer itself … the nearest you will get is to move the pinion to engage differently on the rack [very easy to do]

Whilst it’s apart … take the opportunity to clean any debris from the rack

… too much muck and the spring-loaded pinion can skip a tooth.

MichaelG.

.

Edit: __ posting crossed with Rob’s

[Harry WilkesParticipant @harrywilkes58467]

Ive seen ‘Mr Pete’ on youtube take one apart to adjust it and as Michael suggested gave it a clean, a google search might find the video for you as apposed to going through his play list which is quite high in content

H

[RobinParticipant @robin]

I must be misunderstanding, surely you just turn the dial until the pointer lines up with the zero.

 

[Chris CrewParticipant @chriscrew66644]

“I must be misunderstanding, surely you just turn the dial until the pointer lines up with the zero.”

Yes, you can rotate the bezel and the pointer lines up with zero, but the pointer is at about 3 o’clock when the calliper is fully closed. I was thinking that it should be in the 12 o’clock position which would make the dial slightly more convenient to read when taking measurements. I must say that I am delighted with this device, it seems much easier to use than the digital one I have had for years (or perhaps that’s just my initial enthusiasm?), except that you can’t flip from imperial to metric as before so both types have their uses.

[Ian PParticipant @ianp]

The dial caliper I bought in the 80’s (not sure what make it was) came with a little tool to reset the needle position.

It was a 3cm long piece of what looked like 0.3mm phosphor bronze shimstock with the business end about 1.5mm wide. This was inserted between the pinion and the rack so as to disengage the teeth with the hope that when the strip was withdrawn the teeth mated in the right position, a sort of trial and error technique

I presume there must have been some sprung loaded movement in the pinion that kept the pinion backlash free in normal use. The strip was inserted along the rack face and under the dial.

Ian P

 

[OldironParticipant @oldiron]

Neither of the two I have line up vertically. The zero is offset. Never had a problem with that. I just line the zero up to the pointer.

[DC31kParticipant @dc31k]

When you face a problem of this nature, weigh up the chances of you being the first person in the whole of history to have encountered it.

If after careful consideration, you calculate these chances as anywhere approaching ‘slim’, you could perhaps search the internet, using words such as ‘dial caliper adjustment’.

Post #3:

https://www.practicalmachinist.com/forum/threads/mitituyo-dial-caliper-adjustment.293809/

Size of tool:

https://www.hobby-machinist.com/threads/anyone-have-a-mitutoyo-dial-caliper-adjuster-shim-or-dimensions-of-same.86073/

[David George 1Participant @davidgeorge1]

I have ane of these mechanical Dial calipers and at time a small piece of material gets into the rack and the gear jumps a tooth and you get a false reading. I like the pointer to point to the 90 deg top of the dial so after cleaning  the rack i put the bronze strip into the gap and slide the caliper till it doesn’t rotate the dial. then remove the strip by sliding it out of the rack the gear rotates the pointer and when closed it may point to zero. if it doesn’t repeat the adjustment till I get a correct result. It’s a knack which comes with useage.

 

 

David

[old martParticipant @oldmart]

The needle spindle on Mitutoyo dial calipers is sprung against the rack and if you know how it is easy to adjust the needle position without removing the dial face. As I recall, they used to come from new with a little probe that you inserted at the back alongside the rack to tip the needle shaft out of mesh while moving the caliper head slightly along. It is some time since I did this for anybody at work who had dropped their dial caliper. In the fitting shop we often replaced cracked dial glasses and reset bore mics. All except Tesa bore mics, none of us managed to fathom out one of those.

Making a tool like Davids one would be easy.

[Howard LewisParticipant @howardlewis46836]

Probably, the pinion has jumped one tooth before re engaging the rack.

If you have the tool to disengage the pinion from the rack, you could rest it.

But, if the calliper works satisfactorily, otherwise, my inclination would be to, live withn the dial Zero, just offb the vertical.

As already sai9d,”If it ain’t broke; don’t fix it”  If theb restting process goes wrong, the calliper, in worst case, could be damaged and rendered useless.

Is it worth that risk?

[Michael GilliganParticipant @michaelgilligan61133]

In my opinion, Howard … Yes

Because stripping things far enough to index the pinion by one tooth only really requires removal and replacement of the rack [which can get a jolly-good clean as part of the process].

MichaelG.

[Author]

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