View Full Version : Spring Forward, Micrometers Back

04-24-2005, 12:39 AM
During heating season, my shop temp is 55 overnight, 65 during the day. Now that cooling season is here, it's 75 daytime, 85 overnight.

Checked my 0 - 1 mike today with gage blocks. Reading is .0003 high. Same with the 1 - 2.

Finally got ten OD mikes, twelve ID mikes, and twelve depth mikes back to zero. If your shop temp varies as much as mine, you may want to check the calibration.

Barry Milton

3 Phase Lightbulb
04-24-2005, 01:29 AM
What tempature was your gage blocks? http://bbs.homeshopmachinist.net//smile.gif


Michael Az
04-24-2005, 01:32 AM
Here in the Az desert we can have 40 degree difference in temp in one day.

Forrest Addy
04-24-2005, 01:52 AM

If your Jo blocks or standard are steel and your mikes are steel (or cast iron framed) you should get the same calibration regardless of the environmental temperature - so long as you don't warm the standards or the mikes unequally when handling them.

I think the 0.0003" error represents the effect of your warmer fingers in warmer weather. In cold weather you have lower skin temp differential compared to the ambient air. In warmer temps considerably warmer. It all combines the throw a hitch in your precision measuring unless your take temperature precautions (cotton gloves, handle by the insulators, etc)

04-24-2005, 08:01 AM
I dont do tenths of thousands.
99% of what I do is +/- .010, thank God.

But you do bring up a good point,Climate control.

04-24-2005, 10:30 AM

Once again I believe you found the cause of the error, as I've also noticed a dramatic increase in sweat output.

Barry Milton