Thread: How to read imperial scale vernier caliper?

Each of the tiny graduation marks on the upper fixed imperial scale is 0.25". Therefore the point of the zero on the sliding scale reads 1.55"
Moving on to the sliding scale, each graduation is 0.001"
For this reading, the sliding imperial scale and the fixed imperial scale align when the upper reading is 13 i.e., 0.013"

Final reading = 1.55" + 0.013" =1.563"

Another reason why metric is so much easier than imperial

Both are pretty easy once you've done it long enough but I do prefer metric for any measuring.

Originally Posted by Dengue

Each of the tiny graduation marks on the upper fixed imperial scale is 0.25". Therefore the point of the zero on the sliding scale reads 1.55"
Moving on to the sliding scale, each graduation is 0.001"
For this reading, the sliding imperial scale and the fixed imperial scale align when the upper reading is 13 i.e., 0.013"

Final reading = 1.55" + 0.013" =1.563"

You're close. The Imperial scale is divided into 0.100" and then further divided into 0.025" subdivisions. You can't measure 1.55" on the main scale, but I assume you're just using that number as an example.

Thanks raffo, but I got the 1.55” reading off the imperial fixed scale. It was not a made up number.
I read 1” + .5” + 2x.025” =1.55”.

Originally Posted by Dengue

Thanks raffo, but I got the 1.55” reading off the imperial fixed scale. It was not a made up number.
I read 1” + .5” + 2x.025” =1.55”.

Duh, you are right, I was off by 10!

On the topic of verniers, I got this little vernier from a machinist. I use it as a small square when doing dovetails, but I'm intrigued about it's actual purpose. As you can see it has an accuracy to 0.001".

What confuses me is what can one measure with it. The main scale starts about 1/4" from the end of the bar. Does that mean that this is not used as a depth gauge? How can one measure something with it if one can only reference against one side only?

Any ideas?

Rafael

Ehrmann_vernier.jpg

Originally Posted by raffo

Duh, you are right, I was off by 10!

What's a factor of 10 amongst friends !!!!!

Originally Posted by raffo

On the topic of verniers, I got this little vernier from a machinist. I use it as a small square when doing dovetails, but I'm intrigued about it's actual purpose. The main scale starts about 1/4" from the end of the bar. Does that mean that this is not used as a depth gauge? How can one measure something with it if one can only reference against one side only?

Definitely intriguing! I suggest you re-post this on the Metalworking Forums; there is a wealth of knowledge regarding machinists oddments. I can’t make out the manufacturer’s details; if you do repost it would be a good idea to quote them.

Originally Posted by Dengue

...My problem is reading this in inches on the top sliding scale in the pic.....

No, not really. The problem is that you would want to read it in inches.

You can fix the problem for $25 ToolPRO 150mm Digital Vernier Caliper with Case | Supercheap Auto

Originally Posted by raffo

What confuses me is what can one measure with it. The main scale starts about 1/4" from the end of the bar. Does that mean that this is not used as a depth gauge? How can one measure something with it if one can only reference against one side only?

The vernier graduations on the body also start about 1/4" from the edge, so when the end of the ruler bit is flush with the edge of the body it will read zero. I'd say it's almost definitely a depth gauge.

Originally Posted by elanjacobs

The vernier graduations on the body also start about 1/4" from the edge, so when the end of the ruler bit is flush with the edge of the body it will read zero. I'd say it's almost definitely a depth gauge.

Yes, I eventually realized that that is how it works. Duh again.

I will make a new post here, I don't frequent machinists forums. I need to take a few new pictures later. I have a little bit of information about the inventor.

Here's a better picture of my depth gauge. It's marked J. P. Ehrmann, Watervliet NY. I was only able to find his obituary from 1957. It says he patented this gauge but I was not able to find it under his name in the patent database. It's a remarkable tool, with a 1 mil precision, wasted on me since I don't work to high tolerances.
Rafael

20201231_161437.jpg
CDt5ciKw.jpg

P.S. Apologies for hijacking the thread.