# Should a Micrometer jaws be open or closed during storage?



## Bod (5 Nov 2020)

I have a couple of micrometers to put into long term storage, 1-2 years, should I close the jaws or leave them open(1-2mm)?
One is electronic, the other mechanical.

Bod


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## CHJ (5 Nov 2020)

I was taught to always leave a gap when not in use, back off a quarter turn is sufficient.
Avoids any risk of pressure increase with temperature changes however low the risk.


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## novocaine (5 Nov 2020)

what he said. 
when used they should be opened, the face cleaned with a lint free cloth then measurements taken. 
unless you are using them as a spanner, then it doesn't really matter.


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## kenledger (5 Nov 2020)

When you put them away they should be open definitely about 10,15 thou, that only applies to 0-1inch mics, or what ever millipedes mics are.
Bigger mics do not close right down


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## The_Yellow_Ardvark (5 Nov 2020)

Open.
1/'4 turn and unlocked.


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## Inspector (5 Nov 2020)

I was taught to open them a bit so moisture won't cause the faces to corrode. For longer storage remove the battery and wipe both down to remove fingerprint oils. If you can get any of those little desiccant bags toss them into the box.


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## AES (5 Nov 2020)

+1 to all the above, and as Inspector has already said, don't forget to remove the battery from the digital mic.


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## Bod (5 Nov 2020)

Thanks all.
For the life of me I knew there was something about the how the jaws should be left, but could I remember what it was!
Expansion pressure, and damp creeping in both make perfect sense.
All batteries removed, silca granules added, hopefully all will be well.

Bod.


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## Gerry (5 Nov 2020)

Yes open and the anvils lightly oiled for storage to prevent corrosion.

Gerry


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## AES (5 Nov 2020)

AND, once the instruments come back into use again, apart from not forgetting to put a new battery in, don't forget to clean the faces of the anvils. The "approved" method is to close the faces onto a clean piece of ordinary writing or printer paper, using the ratchet if the instruments have them. Apart from cleaning this also serves to double-check that a 0 to 1 is properly calibrated - remove the paper and then close the anvil faces (ratchet again if poss) and the reading should be zero. If not a 0 to 1, use the test piece provided.

Hope that's not teaching granny to suck eggs!


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## Bod (6 Nov 2020)

Oh no! All good advice most welcome.

Bod


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## novocaine (6 Nov 2020)

honestly, the rubbish you forget, I don't think I've cleaned a mic like that in years, yet the moment you say it a light bulb goes on in the dark and dang portion of the brain I call home about being taught that. 

along with 3 clicks of the ratchet.


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## AES (6 Nov 2020)

Oh, 3 clicks? Never heard that one before (but then again, ALL of my brain is dark and "dank"!).


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## novocaine (6 Nov 2020)

Reckon it was just something the instructor taught us so we didn't clamp the mic down rock to much but unlike the cleaning, that was has stuck. especially when I started having my own gear and didn't want to wear it out.


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## AES (6 Nov 2020)

Yeah, reckon you're right mate. 

In similar vein I DO remember one day while still in basic training, a (civvy) window cleaner was working round the shops and when he got to our area, spied a good qual (nothing less in the RAF) 24/25 caliper on someone's bench. "Ah, just what I need" he says, and before anyone could stop him he'd grabbed it and was trying to open the (screw-on) back of his watch with it! Instructor went MAD!!!!


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## kenledger (6 Nov 2020)

I never gave digital mics a thought in my reply, i'm from the clockwork age.


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## RichardG64 (6 Nov 2020)

AES said:


> AND, once the instruments come back into use again, apart from not forgetting to put a new battery in, don't forget to clean the faces of the anvils. The "approved" method is to close the faces onto a clean piece of ordinary writing or printer paper, using the ratchet if the instruments have them. Apart from cleaning this also serves to double-check that a 0 to 1 is properly calibrated - remove the paper and then close the anvil faces (ratchet again if poss) and the reading should be zero. If not a 0 to 1, use the test piece provided.
> 
> Hope that's not teaching granny to suck eggs!


Nice one


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## HamsterJam (6 Nov 2020)

Batteries - what sorcery do you speak of?  (The mics I used had vernier Scales).
I was taught to always leave open a few turns and also the three clicks rule. Why three clicks? Because that’s enough to get a good reading without wearing the ratchet more than necessary.


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