ChrisTropea
ChrisTropea Associate Editor
1/11/23 10:05 a.m.

https://www.youtube.com/embed/kyZGt2IXLsw

What do you do when that ruler or tape measure isn’t accurate enough? Enter the caliper and the micrometer.

Here is the GRM guide on how to use and read a caliper and a micrometer to ensure accurate measurements.

Presented by CRC Industries.

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David S. Wallens
David S. Wallens Editorial Director
1/11/23 4:55 p.m.

Jazz hands. Okay, not really. 

SSpiffy
SSpiffy New Reader
1/11/23 5:32 p.m.

Just one quick comment. You used 'accurate' and 'precise' as synonyms. In measurement, they are different concepts. Using target shooting as the analogy, accuracy measures how close to the bullseye your shots are while precision measures how close to each other your shots are.

Datsun310Guy
Datsun310Guy MegaDork
1/11/23 6:08 p.m.

In high school I took machine tool and we had to learn how to read a vernier caliper. 

BA5
BA5 GRM+ Memberand HalfDork
1/12/23 8:56 a.m.

I'll add a couple of bits to go along with this fine video.

  1. Always zero your caliper each time you take a measurement. I always give the jaws a wipe, too before I zero them.  You're measuring at the 0.001" scale.  It doesn't take much to be off.  Even more so with a micrometer.
  2. Take multiple measurements, especially when measuring the ID of a hole.  There's a bit of a technique to moving it around a bit to find the actual ID.
  3. They said it in the video, but I'll add to it because it's always worth saying: don't crank down on anything.  There's a bit of flex in the caliper measurement system, you want the calipers to not be under any stress when taking the measurement.

The folks at the magazine probably can't link stuff in their official posts, but I'm under no such constraints.  Here's a brief video showing the different measuring surfaces on a caliper:

Starrett YouTube Video

Starrett and Mitutoyo are generally "the best" as far as measurement instruments like this go.  I personally have a bit of a preference for Mitutoyo equipment.

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