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Bob Quale
09-18-2003, 10:17 PM
I have a digital caliper, six inch. If measuring high in the jaw, compaired to low in the jaw, I get a diference of .007. Is there a gib I can tighten? or can I get it repaired? and is it worth it. It reads to .0005 and was about $90.00US.

Thanks Bob

spope14
09-18-2003, 10:44 PM
Two things, first one a bit drastic, the second one a possible repair and diagnostic method.

1. Sounds like you dropped it or it has been "sprung" on first look. See if there is a way to set it up "square" with the inner beam as the reference, and then indicate the jaws. If the upper "fixed" jaw is out, then replace, no way to fix I have ever tried or seen. If the lower "moving" jaw is out, then you might be able to tighten it up a bit. See 2.

2. I rebuild many calipers a year. On mitutoyo there is a brass "spacer" on the opposite side of the measuring side of the movable jaw. It is under the "lock", and all along the top on the underside right along the back of the beam. You can see it by looking for it by the lock. There are two very small set screws, take jeweler screwdrivers to get into. One might be a bit loose, touch them tight, but not to over tighten. Start your checks again. You should not feel any "slop" on the jaw front to back when it is tight good, but you will have a bit of side to side, very slight - I have my mitutoyos in my hand right now.

The brass shim has a little groove in it, this is for the Back screw, or the one towards the rod end. You must be sure this is correctly placed under the screw, or this will also "off kilter" the movable jaw. Having said this, your brass shim may have slipped over use, the screws lossened a bit, and the shim moved. Does your shim show on one side "outside" of the movable area on top?

Check repeatablilty as well. If it does repeat, your brass shim / gib may not be the issue, but try this tightening anyway.

On a bit of a note, when you tighten the screw on mitutoyos, and most other calipers, but especially on the Mitutoyods with the screw on the far end of the "movable jaw", it will knock it out of kilter. The hint and secret here is that you measure the part, lock the tool if you choose, and read the measurement for what it is at the lock with the appropriate pressure (hope this made sense). Do not "lock" the caliper down to use as a "go / no go" gauge.

I use a gauge pin, drill rod piece, or a 0 taper turned shaft to check my calipers and set the "brass shim", for poor tightening can knock the caliper off square. Try these methods, and if you have a question, re-post or e-mail me.

No guarantees, might be faulty or busted gear. But these are some ways to possibly fix the gear, or make more accurate.


[This message has been edited by spope14 (edited 09-18-2003).]

L Webb
09-18-2003, 10:51 PM
Bob, do a measurement high and low but don't use the thumbwheel. Push on the jaws with your fingers to close in on whatever you are measuring.
Use a gage block or plug gage of a known size and see what the difference is.

How do the jaws look when closed and held up to a light? Any gap high or low visible?

Les

DR
09-19-2003, 10:56 AM
Speaking of calipers, anybody got a clever idea how to make a new crystal (the plastic cover over the dial) on my favorite B&S?

I used to take this stuff to a local guy who was confined to a wheechair, $8 and I was out the door. He died and everyone else wants much more for the job.

pgmrdan
09-19-2003, 12:23 PM
.

[This message has been edited by pgmrdan (edited 03-08-2004).]

JCHannum
09-19-2003, 01:20 PM
DR;
You don't suppose he starved to death do you?

check out www.longislandindicator.com (http://www.longislandindicator.com)

They may be able to help you.

Thrud
09-20-2003, 04:06 AM
I concur with SPope.

DR
Try a watch repair shop. By the Thunderin' Lord Jesus (my best Newphie speak) the next one that breaks on me is getting a Sapphire crystal (flat stuff used on 600M dive watches). http://bbs.homeshopmachinist.net//biggrin.gif

Getting sick of breaking plastic crystals (an oxymoron at best).

spope14
09-20-2003, 10:16 PM
Call MSC for crystals. They call the companies that manufacture the calipers, and get the spare parts. Got three Mity yo - yo crystals for about $6.25 each last June, and replaced them myself. Just need the caliper number and such. School calipers get the hell beat out of them, and if I did not know how to do this, I would be buying three to four sets per year.

Another necessity for caliper repair- Watch hand puller. They run about $60.00 to 90.00 but pay for themselves after three cleanings of the calipers - compared with buying new sets. Pull the crystal and cover, pull the arm easily, take it apart, clean it fully gears and such, and put it back together. Just like new, and even better.

Tried to make my own pullers, many experiments, but the ones I made worked fair at best. Bought the real thing and never once looked back. Buy these through a watch repair shop, they are the neatest things.

Bob Quale
09-20-2003, 11:39 PM
Well, the floating part of the calliper is loose. The part that measures inside diameters is gouged, indicating a definate drop. If I can snug the moving part, can I do something good with it? Grind it down and make it into some other type of measuring device?

Thanks for the help!

Bob

Thrud
09-21-2003, 10:06 PM
Find out who dropped them and then make them replace them. One thing you could do is make points for it and use it as a centerline mic. for holes. B&S sells these for about $100 they attach by set screws.

I fthe gouge is not bad it can be lapped out and the dial reset. Mitutoyo and Starrett repairs their tools for less than new, and you will have a "new" caliper when they are done.

SPope

I have been given free crystals by my local parts dude every time I ordered new one - he must like me.

[This message has been edited by Thrud (edited 09-21-2003).]

chief
09-23-2003, 07:56 AM
Bob,
You'll have to find an individal or yourself to repair mitutoyo, unlike Starrett
they don't repair their tools. They want you to buy a new one.