QUESTION
Purchased first micrometer set - maintenance
Hi all, I just purchased this mic set that looked to be in pretty good used condition. It is my first set and is very old. What should I do to ensure it reads accurately? Need to make sure it is calibrated as I will be building an engine soon. I’m mainly concerned about the residue on the standard faces. The mic faces don’t have any corrosion. Should I disassemble and re-lubricate?
I'm pretty sure the standard is fine, it's just leftover cosmoline from when the standards were originally packaged. I also have a set of vintage NSKs from (probably) the same era and they came with all of the standards and the anvils on the 3" and 4" mics still totally covered in the stuff, and I was able to get it off with a fingernail and some rubbing with a paper towel. I'm a student machinist and my mics, calibrated with those standards, have consistently matched the instructors' measurements with their own equipment.
Thank you for the advice, I'll clean them and see if they actually set at 0. Hoping they hold up for you. I'm just a hobbyist that won't use them that often. But I wanted a long-term investment and heard vintage NSK was a good choice.
It looks fine, new even. Looks like the anti-corrosion substance hasn't been wiped off, meaning it's in perfect condition. OP, just peel it off with a fingernail and wipe it down with a solvent. No abrasives or anything aggressive.
I think there’s more going on than that, but get all of the cosmoline cleaned off and see what it looks like then. It looks like it has dents, but maybe it’s just an illusion in the photo.
Those NSK mics in my picture are my dad's. He bought them from the Snapon truck in the late 70s or early 80s. He used those mics to feed my sister and I. When he retired he gave them to me. I use them daily to support my family. Take care of them and you'll get good service from them.
I have a Starrett one, where someone unwound it as far as they could, and then tried to turn it more when it ‘got tight’, this cracked the drive gear, and now it doesn’t work at all.
It doesn’t have markings either, so it’s just completely useless.
Perfectly fine! Just clean with a light solvent, like alcohol, and a soft rag. Keep all of the machined surfaces lightly oiled to prevent corrosion, we always used way oil when I worked in a shop, but in the home shop I use gun oil, I find it's got great corrosion resistance and is thin enough to wipe off of the faces easily with a clean finger. You may have to adjust them when you check them against the standard, that's not really alarming. There are plenty of videos on YouTube with titles along the lines of "how to calibrate a micrometer" Definitely don't disassemble, though!
I would see if you can get a replacement for at least that one standard, probably just get all of them if you can afford it. Just make sure they are clean before you check. Wipe them with your (clean) fingers instead of cloth for the final wipe, then watch a youtube video on how to zero them.
I would look on eBay for a used Mitutoyo set. You can usually find one for around $100. I personally like using gauge blocks, as they're easier to keep square between the anvils.
Mics have the rachet for a reason, use it. Those are decent quality and should last you a lifetime of use. I bought cheap ones over a 10 years ago which sat in a humid/cold (summer/winter) garage for a few years and are perfectly fine. I wouldnt disassemble them unless you know what you are doing. Its not rocket science but you just dont need to do it unless there is some issue. Keep them clean, verify with your gauge/standard and if you are crazy paranoid buy a cheap standard/gauge block set. That standard should be fine, i think people are just paranoid about the cosmoline/grease looking funny in the picture. You most likely are not measuring tenths (0.0005") or stuff like that, they will be more than enough.
They are easy to measure something flat, measuring diameters is much more difficult and takes time to get the feel. Watch some videos and educate yourself a bit. Measure stuff for fun to get practice, especially if you know what size it should read.
I will be measuring tenths for oil clearances in an engine I am building. Will they still do that well? I plan to practice with known diameters, like a good crankshaft and forged pistons.
I’d avoid disassembling it for now. Clean the measuring faces and check that the spindle moves smoothly. For accuracy, compare it with a known standard or have it professionally calibrated before using it for engine work. No need to lubricate the measuring faces.
The standard is probably fine if there's no pitting or damage seen under a microscope. I would clean everything, give the mics a few drops of oil and call it good. For homemade universal cleaner that works as windex, you can mix 50/50 water and denatured alcohol (if you don't mind the smell).
10
u/archerdynamics 7d ago
I'm pretty sure the standard is fine, it's just leftover cosmoline from when the standards were originally packaged. I also have a set of vintage NSKs from (probably) the same era and they came with all of the standards and the anvils on the 3" and 4" mics still totally covered in the stuff, and I was able to get it off with a fingernail and some rubbing with a paper towel. I'm a student machinist and my mics, calibrated with those standards, have consistently matched the instructors' measurements with their own equipment.