Old Mitutoyo 505-626 - easy re-clocking dial.

[Shadowdog500]

Decades ago my first dial caliper was an old beat up Mitutoyo 505-626 that could easily be re-clocked to zero in seconds using a push pin that came with it or a paper clip. Those calipers are long gone to who knows where, and I understand that the current Mitutoyo calipers do not have this feature. After having to take apart my cheap Chinese caliper to re-clock it by removing and resetting the hands, I decided to get another old Mitutoyo as a beater that may get dropped and easily re-clocked so I bought this one for $45. Nice old ones are over $100.



The rack was full of black **** that I easily cleaned off with an old Sensonic tooth brush but the pinion must have been loaded with stuff too because the pointer hand axle wasn’t staying perfectly centered when I opened and close the caliper jaws.
I took it apart and the inside was dirty and someone was definitely in it before

I was surprised that the mechanism was so simple and there was no preload spring like modern ones.


This is how the pin disengages the pinion from the rack to re-clock the hand.


I checked and each tooth is 0.020” on the dial



The pinion was filthy so I removed it along with the spring steel that it is mounted to



Here is a close up by holding a 20 power loupe to my phone camera then zooming in



I cleaned that with the sensonic toothbrush and reassembled. The pointer axle stays centered now.

Resetting the bezel

 

[paulsomlo]

That apparatus that you use for resetting the bezel - are you engaged in watch repair or indicator repair?

Does "down the shore" imply NJ?

 

[OccupantRJ]

If jumping the pinion to the proper place is all that is needed it can be done with a narrow strip of thin shim stock by going in behind the indicator section. The tools used to come with new calipers but often get lost.

 

[gleman]

That apparatus that you use for resetting the bezel - are you engaged in watch repair or indicator repair?

Does "down the shore" imply NJ?

The crystal press, parts holder, loupe and tiny screwdrivers are a pretty good indicator.

 

[RoninB4]

-This can also be done by removing the end stop and slowly/carefully pulling the carriage off the beam. Take note of how far off zero the needle was before disassembly, take note of where the needle is when off the beam. Use a small piece of wire or paperclip on the needle axle gear to move the needle to the appropriate location and carefully slide the carriage back on the beam. It may take a couple of tries to get it right but it works when the factory supplied shim gets lost.

 

[Shadowdog500]

That apparatus that you use for resetting the bezel - are you engaged in watch repair or indicator repair?

Does "down the shore" imply NJ?

I’ve been a tinkerer my entire life and have several Seiko watches. I decided to fix one of my old watches a few years ago after watching wristwatch revival. The basic tools can be purchased pretty darn cheap, but I did wind up buying more expensive tools when the cheap tools were total garbage. I also bought a box of broken cheap watches for about $20 to practice on.

My younger eyes could read micro print without a magnifying glass but my current my older eyes are just barely good enough to thread a needle so I had to use strong loupe to work on the fine parts of a watch, and will eventually need a microscope with a Barlow lens.

I found that dial indicators and calipers have larger mechanisms that are way easier to see so I will work on my own with no problem.

“Down the shore” does mean south Jersey.

That watch back tool was only $20. For another $10 I can probably get dies for the press to replace the crystal.

 

[Steve_P]

Fantastic. Not that I will ever do this, but how did you remove the glass bezel?

 

[Steve_P]

If jumping the pinion to the proper place is all that is needed it can be done with a narrow strip of thin shim stock by going in behind the indicator section. The tools used to come with new calipers but often get lost.

I bought my first Mitutoyo dial caliper (from McMaster so it's legit) ~15 years ago and it didn't come with that tool.

 

[Shadowdog500]

If jumping the pinion to the proper place is all that is needed it can be done with a narrow strip of thin shim stock by going in behind the indicator section. The tools used to come with new calipers but often get lost.

There are two different method to re-clock the older Mitutoyo 505-626 calipers depending on the year it was manufactured. The years that the bezel locking screw screws go into the lower jaw frame uses the shim stock because there is no way to get a pusher pin into the dial body. The years where the bezel locking screw screws into the dial body came with a push pin, and you remove the locking screw to insert the pin.

Here are instructions for the push pin model like mine.

This is the often lost Mitutoyo push pin that came with the caliper.


Here are Mitutoyo instructions for the push pin type that I found online.





Here is a video that shows how to adjust both versions. I would have used a 123 block to set the jaws at an even inch or two before pulling the shim stock.

 

[Shadowdog500]

Fantastic. Not that I will ever do this, but how did you remove the glass bezel?

The bezel is a friction fit, you just pry it off carefully.

This shows how a bezel is removed on a Starrett last word indicator, but the bezels on my dial indicators and dial calipers all come off the same way.

 

[Shadowdog500]

I bought my first Mitutoyo dial caliper (from McMaster so it's legit) ~15 years ago and it didn't come with that tool.

I believe the new ones use a tension spring assembly and there is no way to easily re-zero the hands. Yo need to pull the bezel and hands and reinstall them like I did to my inexpensive Chinese inch/metric ones.

Here’s how I reset the hands on my Chinese ones.

I pried the hands off with a set of $5 watch hand removing lever bars.




I did buy a set of three of these face protectors for $9 after that photo because they protect the face of the dial better than the plastic bag, especially on indicators where the hands and the shaft they mount on are a bit larger than a watch.


I reinstalled the hands using one of these better quality hand setting tools which was about $150 on ebay. The cheap $15 hand set tool set was junk and my Seiko watches are pilot watches with multiple complications (extra dials)




This is what my watches look like, the little hands on the complications are a pain in the **** to see and install.

 

[gagecalman]

This is giving me flashbacks. I used to repair and calibrate pretty much anything mechanical that you can measure with. Mics, calipers, indicators, bore gages, torque wrenches, even hardness testers and optical comparators.
I have some of those brass tools but most of the time it was easier to pull the hand with the puller on the left.
The older MItutoyo calipers with 0.200" per revolution just has a spring loaded pinion. The tool works okay for those.
The older ones with 0.100" per revolution have a more elaborate movement with several gears and a hairspring. Sometimes they get damaged using a shim tool.
Thanks for the memories.

 

[Shadowdog500]

This is giving me flashbacks. I used to repair and calibrate pretty much anything mechanical that you can measure with. Mics, calipers, indicators, bore gages, torque wrenches, even hardness testers and optical comparators.
I have some of those brass tools but most of the time it was easier to pull the hand with the puller on the left.
The older MItutoyo calipers with 0.200" per revolution just has a spring loaded pinion. The tool works okay for those.
The older ones with 0.100" per revolution have a more elaborate movement with several gears and a hairspring. Sometimes they get damaged using a shim tool.
Thanks for the memories.

Now I know where all the hand rested tool went! LOL! I bet you have a large collection of 10mm sockets too! LOL!

Your hand puller on the left looks like a genuine Bergeon presto hand removal tool that currently sells for $150. I hear they work well.

The first hand puller / setter set I bought were knockoffs of ones they sell on Esslingler and were total garbage! For $15 it was worth the price to give it a try.

 

[gagecalman]

It is a Presto 4.

 

[Shadowdog500]

It is a Presto 4.

Thanks! I just looked up the Bergeon Presto 4 and 7 and like that they push against the cannon pinion instead of the dial face! I can see how that would be much better for these indicators because this immediately made me think about the load on the pinion holder spring when I pulled the hands. Your post just cost me money! LOL!

 

[gagecalman]

A lot of times if you pry against the face on the older calipers with 0.200" per revolution you'll pull the pinion out of the spring holder.
You will not pull it out of the older ones with 0.100" per revolution. They have a different setup. The pinion is held in the movement and does not ride on the rack.

 

[Shadowdog500]

It is a Presto 4.

Your post did cost me money. I just bought a new old stock Presto 7 on eBay for just under half the cost of a new one.
I checked and it’s supposedly the best hand remover for my Seiko watches and I confirmed that the pinion diameters on my dial calipers are within the range of the Presto 7.