Checking up on an old friend Please
click the small photos for a good look
Caliper Jaw Bur
© Frank Ford 2010; Photos by FF
Not as accurate as a micrometer, but many times more handy, my digital caliper gets lots of use in my shop. Before use, I grip a piece of paper in the jaws and slide it out to clean them up. But lately, I've had a little inconsistency in measurement - not much, but just enough to notice. As I looked carefully at the jaws, they appeared completely clean:
. . . until I held them up to the light:
I could see what looked like a tiny piece of contamination, but it would not go away with my paper cleaning trick, so I figured it was something else, and sure enough, with a really close look, I could see a tiny ding in the edge of the jaw:
You'll want to click the photo above for that closeup look, where you can see the metal displaced upward.
A quick "stoning" with my favorite little flat sanding block - the six inch scale and some 600 grit abrasive paper:
Now, I can see I'll have to reset zero:
Just for fun, here's a photo of the setup I used to take the picture of the light behind the caliper:
