Micrometer Standard Set?

[owl]

One caution, for your larger standards, they are very temperature sensitive. A 10" standard will grow .00065" for every 10 degree Fahrenheit rise. Of course if the mic and standard both have similar temp rise, there could be cancellation errors.

 

[kd4gij]

Our calibration lab uses gage blocks to calibrate the mic's.

 

[T Bredehoft]

A 10" standard will grow .00065" for every 10 degree Fahrenheit rise

You're number's right, I always did it this way. On a calculator, enter inches, enter difference in temperature in f, enter 5 0's (.00000) followed by 66, 63 for cast iron. hit enter. After a while you get good at feeling differences in temperature.

 

[Uglydog]

Another option might be to use end measures. Especially for very large sizes. Certainly cheap enough.

Daryl
MN


Sent from my iPhone using Tapatalk

 

[British Steel]

You're number's right, I always did it this way. On a calculator, enter inches, enter difference in temperature in f, enter 5 0's (.00000) followed by 66, 63 for cast iron. hit enter. After a while you get good at feeling differences in temperature.

Some of us have sources of Invar 36 bar ("take it away, we need the space and we lost the certificates...") - so add another zero*, and access to Zeiss Coordinate Measuring Machines used for *calibrating* other CMM standards, at work....

If you have a few good known length standards, then anything else can be calibrated from 'em with a little ingenuity!

I love the skip at work - even though my boss says it's "unprofessional", I'm not giving up my intimate relationship with it
Now I wonder whether they're going to scrap any Inovco... $

Dave H. (the other one)


* 1.2 ppm/C, 0.67 ppm/F
$ 0.55 ppm/C - but only from 20 - 100 C...

 

[Tony Wells]

oooh Invar......good stuff