Lesson/WARNING Of The Day: Mahr Millimess Indicator

[Paul Alciatore]

While playing around, measuring my 1-2-3 blocks after stoning them, I decided to lubricate my Mahr Millimess indicator. It is about 40 or more years old and it tends to stick when it is stored. It would work after holding the plunger down for a minute or two but the next time it would stick again. So I opened it up and added just a fraction of a drop of light oil at the jeweled bearings and wiped off the excess. I hope that was the correct thing to do. I will find out tomorrow when I test it after sitting overnight.

But then I noticed my oily fingerprints on the face after I replaced it so I decided to clean it, with alcohol. That was a mistake. Who would have figured that those 1950s or 1960s Germans would have printed the face with ink that would dissolve in alcohol. Well, they did. I did notice that the markings were being cleaned off before any of the scale markings were erased, but some of the text was gone.

So, be warned. If you open up a Mahr Millimess indicator, DO NOT CLEAN THE FACE WITH ALCOHOL. Perhaps this is well known, but I certainly did not know it. I wonder if they still use such a fragile ink. And I wonder if other manufacturers of indicators do anything like this.

[nickel-city-fab]

OUCH thats gotta hurt.... those Mahr indicators are *not* cheap, and they are very very good... I have a policy of not "cleaning up" old indicators. I send them into Long Island Indicator because I paid some good money for my Compac and Federal indicators. I learned the hard way using CRC Brakleen on a junk indicator -- it removed *everything* that wasn't metal.... BTW yes, most inks are based in either water or alcohol, they usually use alcohol when they need a fine line because the way it wets out allows a very fine mark. (former fine art student....)

[Black Forest]

Note to Paul: Drink the alcohol and don't clean up anything. The more alcohol you drink the cleaner your shop will seem!

[old mart]

When I needed to clean a dial from an indicator, I always played safe and very gently used a weak detergent solution in luke warm water. Even that was slightly risky at times.
As for oil, then getting proper watch oil is recommended, applied with a long needle.

[Tungsten dipper]

Alcohol is a good way to tell the difference between enamel and latex.

[Doozer]

I get some pretty crusty and dirty old indicators from work
that QC is throwing out. Some very nasty from coolant mist
in the shop. One thing I have found to clean the faces of the
indicators without hurting the clear plastic, is Hoppes No.9
gun cleaning solvent. I have cleaned many dial indicators
with it, some so crusted with brown film on the face that you
can't see the numbers any more. Never did it mess with the
plastic. Never made them haze or anything. But it does clean
the goo off very well. Just thought I would mention this if
it can help.

--Doozer

[MichaelP]

I get some pretty crusty and dirty old indicators from work
that QC is throwing out. Some very nasty from coolant mist
in the shop. One thing I have found to clean the faces of the
indicators without hurting the clear plastic, is Hoppes No.9
gun cleaning solvent. I have cleaned many dial indicators
with it, some so crusted with brown film on the face that you
can't see the numbers any more. Never did it mess with the
plastic. Never made them haze or anything. But it does clean
the goo off very well. Just thought I would mention this if
it can help.

--Doozer

I'm a bit confused. Do you use it on the dial (scale) itself or on the lens?

Mahr Federal lens can be easily and safely cleaned by rubbing alcohol, but I never tried (or had a need) to clean the printed scale.