**outside dimensions**- think of a tube. This would measure the outside diameter. The "pike" on top of the hatchet is used for measuring

**inside dimensions**. Again, think of a tube's inside diameter. Looking all the way to the right...I know it's hard to see...but there's a little "tail" sticking out of the center of the handle. That will measure the

**depth**of a step or some other similar feature. That little button on the top near the "pike" is a locking screw. The one just below it is a thumb button.

**Signing Up**

Thanks for the great refresher! I hadn't used my vernier in several years and was really rusty when I tried to use it. The pictures and text were great, they brought me right back up to speed so I can now reload with confidence. My vernier is an older Craftsman and has both inch and metric scales.

I have a master's degree; I took a total of 7 years of math in high school and college. I made A's in English and reading comprehension. But I cannot follow these instructions. I have the cheap Harbor Freight calipers mentioned by a reader previously. They have different scales. I realize the principles would be the same but I don't understand what I am reading; I go back to the pictures but they aren't helpful. Annotating the pictures would be helpful so I know what they description is referring to. I'm not suggesting you do that since you put a lot of work into it. But I still am no closer to learning how to use these calipers than I was before.

It appears that you have a very unusual caliper.

But let's see what's going on here.

On that central bar that doesn't move, you have 2 scales - one on top of the other...they both start at zero on the left. The bottom scale starts at zero, has divisions, and the first number is 10, then there's 20, and 30, etc. The top stationary scale starts at zero, there are some divisions an then there is a big 1, some more divisions and then a big 2. So it appears to me that the top scale is in inches and the bottom scale is metric. I know this because I also know that 1 inch equals 25.4 millimeters. If you look where the 1 on the top stationary scale coincides with the bottom stationary scale, you will see that it lines up with a number just past 25.

OK. Let's test that. Look at the moving scale at the top...near the "pike". It start off with zero, there are 3 lines and the fourth line has a 4, three more lines and at the fourth line there is an 8. It says these are divisions of 1/128 in...but we'll get to that later. Line up the zero of that top moving scale with the 1 on the top stationary scale as exact as possible. Now look at the bottom moving scale that starts with zero at the left and every other division is increased by 1. I'll bet you, that while the zero on the top moving scale is lined up exactly with the 1 on the top stationary scale, that exactly at that moment the zero on the bottom moving scale is just a little bit to the right of the big line between the 20 and the 30 (that would be 25) on the bottom stationary scale. Additionally, the 4 on the bottom movable scale lines up exactly with one of the lines on the bottom stationary scale.

Tell me how I did, and then we'll continue.

You can write to me at blackslax@aol.com

Thanks that was an excellent review.

Users like yourself is exactly why I wrote the instructable.

And the one thing I like about the (old fashioned) vernier is that they are far more durable than the dial calipers. Drop that dial caliper once and your chances are 50-50 that its a goner.

That's like saying it's cheating using a level instead of a clear plasstic tube and water.

There's no question about it - dial calipers and digital calipers are easier to use - especially for those of us that remember the Beatles.

Thanks!

http://www.physics.smu.edu/~scalise/apparatus/caliper/tutorial/

Thanks!

Thanks!

Thanks!

Thanks!

I had to go through 4 or 5 close-ups to get these.

They say a picture is worht a thousand words...but not blurry pictures.