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Bad Mitutoyo Calipers!

rwm

Active User
H-M Supporter-Premium
#1
This seem crazy. I bought these 4" Mitutoyo calipers brand new from Amazon about a year ago:
61Ok9wLOAML._SL1500_.jpg

I have been having a lot of trouble fitting shafts into bearings recently and I could not figure out why. I was having to give the bearing extra clearance by trial and error to make it fit. It thought I was doing something wrong but I could not figure it out.
Finally I decided to check my calipers. On a precision ground .750 shaft the Mitutoyo reads 0.745. My cheap-ass Northern tool caliper reads .749. Even more distressing is that the inside and outside calipers are ground wrong and do not agree.
Here's how it tested this. Tell me if this is not valid. I put the Norther Tool caliper on the shaft and got a reading of .749 and locked it at that setting. The Mitu reads .745 on that shaft. I then put the inside calipers of the Mitu inside the blades of the Northern and got a reading of .751.
Conclusion: There is .006 difference between the grind of the inside and outside calipers of the Mitucrapo. The Mitucrapo is also calibrated incorrectly for OD.
I am really displeased after spending this kind of money on a caliper. I should have caught this sooner when I could return it but it took me a year to figure it out. I should note that the device has never been dropped damaged or used as a pry bar.
What are your thoughts on this? The device is junk unless Mitutoyo will replace it. What is their warranty and has anyone used it?
Robert
 

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rrjohnso2000

H-M Supporter - Premium Content
H-M Supporter-Premium
#3
Amazon is not immune to counterfeits. In fact a major reason I don't buy much from there anymore. Good luck hopefully it's just a fluke and they'll get you fixed up
 
S

steve323

Guest
#4
Maybe I am stating the obvious, but do you need a new battery? The display in the picture looks a bit dim.

I switched back to dial calipers because I got tired of always having dead batteries in my cheapo digital calipers. I have heard that the better brands have much longer battery life.

Steve
 

rwm

Active User
H-M Supporter-Premium
#5
I looked at the counterfeit web page and I believe it is genuine.
Additional info: I just checked the ID blades of the Mitu against my Starret micrometer. I am seeing an error of about 3 thou. My Northern reads dead on to within 1 thou. There is again a discrepancy of 5 -7 thou between the ID and OD blades. This thing is definitely jacked up. I will call them but of course I am 1 month out of warranty.
R
 

brino

Active User
H-M Supporter-Premium
#6
rwm,

At least you have figured it out!
I hope you did not lose too much time or money in materials.

-brino
 

Holescreek

Active User
Active Member
#7
I've repaired hundreds of Mit calipers and never seen one come from the factory with this condition. Assuming they were good a year ago when you received them the fix is probably very simple.
With your thumb push the jaws closed until they stop (but don't apply a lot of pressure) and hold the caliper in front of a bright light and look for gaps between the jaws. Typically the tips will touch and the gap will be closer to the handle. Sometimes I find a burr on one of the jaw tips from the caliper getting banged against something and just stone it off and the problem goes away but more often than not the gap is caused by the front gibb screw coming loose. The gibb screws are on the top on each side of the lock screw. Tighten the front one in or out to adjust the gap between the jaws then the rear one to adjust how snugly the reader head moves over the handle.
 

rwm

Active User
H-M Supporter-Premium
#8
Holescreek! You are the man! You just made my day. Sure enough there was a small light gap at the tips. The jaws are in perfect condition but front gib screw was very loose. I tightened it removing the gap. It now reads exactly .7500 on the test bar and the ID blades mic to exactly .750
My apologies to Mitutoyo for some of the negative comments above. However, this is why I post on this website. The depth of talent is remarkable. I hope the post will be useful to someone else. Everbody check your gib screws!
I must say, this caliper was off when I first used it I just didn't realize it. That screw may have come loose in shipping and gotten progressively worse until the error was obvious prompting me to check it.
Thanks again!
Robert
 
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Holescreek

Active User
Active Member
#10
The front gib screw has a point on the end that fits into a hole in the brass gib. If it gets loose enough the gib will fall out. I've seen people put a dot of fingernail polish on the threads above the screw to keep that from happening.
 

4gsr

Global Moderator
Staff member
H-M Supporter-Premium
#14
You commenting about trying to make bearing fits and not getting shaft to the correct size. Calipers were never designed to make bearing fits, period. We are all guilty of doing this, I included. When you have to make precision fits, get your mics and telescoping gages out, that's what they are made for.
 

Holescreek

Active User
Active Member
#17
I don't own an inside mic either, wouldn't use one enough to make it worth while. I rough the hole in checking it with calipers then switch to telescope gauges if I don't have the right size gauge pin. If it's really critical the next step is a bore gauge. For the average hobbiests the caliper is the first step before using the mating part to get a fit. Not many here are subcontracting to NASA.

In my home shop I'm still using the first pair of Mitutoyo dial calipers I bought when I started out in 1981. I'm very confident using it to the nearest .001" of anything I need to do. I only break out the micrometers when holding tenths (.0001") is a requirement.

At night I work in a quality lab with the most sophisticated measuring equipment a large corporation can buy. We just got a brand new $163,000 roundness tester installed yesterday right next to the old one that seldom got used. There's 7 large CMM's running 24/7 too. But when someone comes into the lab with a problem most of the time it's the calipers and/or gauge pins that get reached for first.
 

dlane

Active User
H-M Supporter-Premium
#18
I don't think locktight will harden if exposed to air , it is ment to crystallize inside threads.
A small drop of superglue, nail polish is what I would suggest
 

rwm

Active User
H-M Supporter-Premium
#19
Thanks again. You saved me an embarrassing call to Mitutoyo. The actually have an office here in CLT.
R
 

stupoty

Active User
Active Member
#20
I don't own an inside mic either, wouldn't use one enough to make it worth while. I rough the hole in checking it with calipers then switch to telescope gauges if I don't have the right size gauge pin. If it's really critical the next step is a bore gauge. For the average hobbiests the caliper is the first step before using the mating part to get a fit. Not many here are subcontracting to NASA.

In my home shop I'm still using the first pair of Mitutoyo dial calipers I bought when I started out in 1981. I'm very confident using it to the nearest .001" of anything I need to do. I only break out the micrometers when holding tenths (.0001") is a requirement.

At night I work in a quality lab with the most sophisticated measuring equipment a large corporation can buy. We just got a brand new $163,000 roundness tester installed yesterday right next to the old one that seldom got used. There's 7 large CMM's running 24/7 too. But when someone comes into the lab with a problem most of the time it's the calipers and/or gauge pins that get reached for first.
I use the telescoping gauges from mitutoyo for inside diameters , they go very very small and are quite cheep for what they are (i got mine second hand)

I purchased a cheep set of telescoping gauges first, i cant even begin to say how bad they were, i took them apart to try and polish the surface finnish to make them work repeatably but found they were beyond repair. They went in the scrap bin. On the other hand the small hole gauges that are like an expanding ball were ok in the cheep variety, could be better but still ok. Ok ok rant over :)

Stuart
 

Wreck™Wreck

Active User
H-M Supporter-Premium
#21
I would never use calipers for measuring bearing bores as they are not accurate enough for that, in sub 1" bores I use a Mits dial bore gauge but find that I can hit -.001 accuracy with a telescoping gauge and micrometer, this is after 20+ years of practice however, the bore gauge is much faster if one has to measure 50 parts per day.
 

EmilioG

Active User
H-M Supporter-Premium
#23
If anyone buys Mitutoyo tools from Amazon, make sure the seller shows: Sold and shipped from Amazon.com,
they are a distributor for Mitutoyo. Anyone else is a gamble, except for maybe TraversToolCo. Caveat Emptor. :)