"Ben" wrote in message
. ..
I just found out JO bloks increase in size over time naturally?????
Also they expand .0000115 * Length for every 1.8 dgrees F above 68
degrees.
They are calibrated with grren light due to its short wavelength.
If only i could find out what wringing means, how its done.

If you're interested in a short article I wrote about wringing a couple of
years ago -- based on an interview with NIST's top gage-block guy -- I could
send it to you. Or I could post it here, if a few others wanted to see it. I
think it's only around 600 words.

Ed Huntress