Inside/Outside Caliper: Special Purpose? Any ID Thoughts?

wlwhittier

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Well...it wasn't purchased today. More like a couple years ago, maybe.

I know it's a caliper, and the joint is unusual (box?). The ends, when fully closed, are NOT the same dimension (inside vs outside).

My queries are: What is the correct name for this tool, and IS that a box joint? The adjustable stop suggests lathe-work, but I'm not sure about that.
It appears to be shop-made, rather than mass-manufactured; or perhaps a school or apprentice project.
I cannot make the name come up anywhere.

Whatever comments or information you would care to make will be gratefully received, and acknowledged. Thanks!

Warren


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It is not what I would call a box joint. A box joint has one jaw inside the other jaw. They are not used often as they are more difficult to make. Hemostats commonly use a box joint.
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I believe that the separation between the contact points is meant to be the same which would allow you to measure the diameter through a necked down opening. One or more of the beams may have been sprung.
 
Nice calipers.

I think I would be tempted to refer to them as "firm joint" as opposed to box joint, although the joint is a bit more refined than many run-of-the-mill firm joints usually seen.

As to the inside-outside description, I still see them being sold as such and can't find a different nomenclature for that style. Proportional calipers do exist and look similar, but they have a movable pivot location so that different ratios can be set for enlarging/reducing. This is not the case with yours. I'm thinking that the discrepancy between inside and outside measurements is a result of modification, possibly due to earlier damage to one of the tips or maybe just because that's what a previous owner needed to do to get into a small space. Typically one would want them the same so that, for example, you could measure the outside lip of a turned box and with the same setting turn the inside of a lid to fit. No need for transferring from one caliper to another. If you look at the shape of the inside feet, they're decidedly "stubby" compared to the nicely refined shape of the outside set.

I couldn't find anything on the maker either, although in my experience at trying to hunt these guys down by individual stamp is pretty hit and miss. I wouldn't guess it as an apprentice piece though -- they would unlikely have their own stamps at that stage.

I'll look through my old catalogues at home and see if I see anything different. Nice piece though!

-frank
 
I don't care what you call it, I like it and could use it at my wood lathe.

I'm like that, Greg: Call me whatever you like...but not late for supper!

Thanks for the comments!

These little beauties will be listed on eBay this coming week. My username is warmo.

Warren
 
It is not what I would call a box joint...

Right you are, RJ: one leg inside the other. These are cleverly made so the legs are on the same plane either side of the hinge...but not boxed.

An inset lapped joint, maybe?

I probably should have thought of that, huh? Sigh...

And; nothing sprung, but the inside tips could very well have been reduced, because of damage or for purpose, as francist mentioned. I suppose the outside points may have been changed, too...but they're so very close to .500" that I would question that.

And I wish I owned that beautiful collection of Lady-Legs...Lovely, indeed!

Thanks, both of you for your spot-on observations!

Warren
 
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