Digital Calipers

[Ron Nossaman]

> Paul,
> I was informed by several machinists that you should NEVER store your 
> calipers or micrometers in the "closed" position. Due to the expansion 
> and contraction of the metal the "frame" will warp, if you do. Of course 
> you should wipe the micrometer or calipers with a very light oil to 
> prevent any corrosion. Also, I'd advise that you store your mics & cals 
> in the box they came in. This will keep the dust and abuse away, IMO. 
>  
> Joe Garrett, R.P.T. (Oregon)


As far as I know, I haven't ruined either caliper or mic by 
storing them closed, possibly because I don't store them 
closed, but storing them slightly less than closed hasn't been 
noticeably detrimental to their accuracy through a lot of 
years in often less than benign circumstances. Since it 
doesn't cost anything to not find out the hard way that 
storing them closed is harmful, I remain a slightly open 
storer. Hey, why would I risk a $15-$60 precision tool over a 
period of 20 years determining the veracity of a single 
premise when I can more nearly immediately risk a $50,000 
piano testing a whole different set of generally accepted 
premises and learn a lot more much faster? No contest! On a 
positive note, I can report a conspicuous lack of corrosion on 
the jaws/anvils when (but not necessarily resulting from) 
storing them open. The fact that these tools are often made 
from stainless steel could be significant, and should be 
factored in.

Seriously, not having done it any other way, I can't say from 
experience what the penalty might be for storing jaws closed.
Ron N