[Metrology] Help, with a micrometer

Bi11Hudson

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Help!? I'm not real sure this is the proper forum. But it does seem like a good place to start. I know the basics of what I have but would like to know details on setup and usage. I figure to get someone that knows what he's doing to help out.

I have been watching, on several sites, for what I suppose is a specialty micrometer. Measuring from zero to two inches, as much as a curiosity as needing something larger than one inch. I found one on eBay, and curiosly was the only bidder. I have several 1" mics, one B&S, a couple cheap Chinese, and a couple of specialty mics for such things as measuring wall thickness of tubing. The one I just acquired is a Brown & Sharps as well. I seem to have a preference for B&S over Starrett. No particular reason beyond what my uncle used when he was a practising engineer. The photo first, then the question(s).
Micrometer0-2.jpg
I'm sure anyone that knows eBay tools will recognise the background. The knob on the left side is the clamping screw to hold the sliding mandrel(?) in place. I assume that to set the 2" span, one uses a standard and sets the barrel to 0.000. Then slides the mandrel up to the standard until it's snug and sets the clamping screw. A standard wasn't included but I have a couple on hand. That covers the basic setup. And I do know how to read a mic. So, with that out of the way, my curiosity question(s).

First of all, the mandrel is removable as well as adjustable. Is it intended to be replacable with specialty ends? Such as the ball end used to measure tubing. Or some other "custom" anvil for a specialty (proprietary?) use.

Second: Is my assumption correct for setting up, using a 1" standard?

Third: And this is purely speculation; can the mic be used for a "minus zero and plus whatever" measurement on a production line of some sort? I can see where the base anvil could be set to most any dimension for "zero". If so, how might such a measurement be used? Or just a QC measurement?

I would appreciate any logical input. As well as pure speculation with an explanation of how or why. In all likelyhood, I will set it up for 0-1" and leave it there unless I have a need (rare) for a 2" mic. Putting it in the same drawer as my existing B&S and grabbing whichever comes to hand. As stated, I wanted it as much for a conversation piece as anything. I'd just like something useful to add to the tall tales. . .

Bill Hudson​

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On my 127 it holds the anvils the same way but there is jam nuts on the anvils so that you can set it to a precise number
 

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@Bi11Hudson

Pure speculation:
Based on the look of it I wonder if the left anvil (usually the "fixed" anvil) has two grooves in it.
We see one in the image above, I suspect the other is locked in the frame by the knob on the left.

The left anvil would shift to two different positions, one for measuring 0-1" and the other for measuring 1-2".
The two grooves on the anvil provide only two fixed positions it can be lock into.

-brino
 
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It is a curiosity, but would be pretty clumsy to use, a nice collectable, I have one just like it, not to use, but to enjoy owning. No coincidence that no body makes them anymore.
 
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