What's this called?

I need to measure the thickness of something that is surrounded by a raised border thicker than the item I want to measure. A calliper like this would do the job, but I don't know what its called and can't find anything like it. Any ideas?

Double ended caliper.  lots on ebay, Amazon, Proops, RDG tools etc

Edited By Bizibilder on 16/02/2023 16:02:12

Dunno what it's called - maybe double-ended caliper - but why not just make or find a flat piece of known thickness greater than the depth of border that fits inside the border, insert it, measure the total thickness, then subtract the thickness of the insert?

Edited By Mick B1 on 16/02/2023 16:02:04

https://www.chronos.ltd.uk/product/double-ended-outside-calipers-6/

Woodturners use this sort of thing.

Thank you. I tried X-calliper and cross-calliper. I didn't think of 'double ended'.

Mick: Unfortunately, the item I need to measure is on a curved surface.

Try Axminster Tools Under Woodturners Calipers

I need mote Coffee … I’s just taken me five minutes to realise that Gary’s illustration represents the shape of the calliper, and is not a drawing of a Möbius strip

MichaelG.

Michael G,

Do i correctly recall a Mobius Bottle?

Also I seem to remember something about a piece of amusing doggerel or poem about it?

Regards, Martin

A friend wanting to measure the thickness of his car fibreglass bodywork made a lash-up double ended caliper with a 80cm throat at one end and a 30mm stroke dial indicator at the other. He made a calibration table to interpret the readings.

Ian P

.

Very nearly

**LINK**

https://en.wikipedia.org/wiki/Klein_bottle

MichaelG.

Ditto, Michael.

Even now my brain says it's a 3D ribbon loop, that flips between an inside and an outside centre-riveted continuous strap.

Holding the image flat in two pieces of sheet metal fashioned (as Gary intends), into a double ended caliper is a struggle.

Something stronger than coffee at work?

Cheers,

Sam

Yes, mobius was the first word that came to my mind when I looked at it.

Such double ended calipers are used by cylinder-head modifiers on car and motorbike engines for measuring how much thickness of metal is left between an enlarged port and thin air or the next port etc when grinding out the ports. So might be available from automotive tool suppliers.

Now I come to look at it, it does look like a Mobius strip. Here's a photo of the 3D equivalent - a Klein bottle.

Double glazing measuring tool…

https://www.upvchardwaredirect.com/double-glazing-measuring-tool-glass-gauge-15494-p.asp?gclid=EAIaIQobChMIgqXzzp-c_QIVyMLtCh2fhAATEAQYAiABEgIKnPD_BwE

Eine Kleine Frage:

The liquid in the bottle seems to be above the level of the outlet; is air pressure keeping it in?

You fill it by pumping the liquid through a thin pipe inserted from the bottom and threaded through the 'loop' part. Emptying is the same, but you have to suck instead.

Can't imagine what it might be but is there a practical application of the Klein bottle ?

Thanks. I think I had forgotten that the essential feature is that there are no conventional openings in the bottle.

Found this on the 'net.

A mathematician named Klein
Thought the Möbius band was divine.
Said he: "If you glue
The edges of two,
You'll get a weird bottle like mine."

I'll get my coat.

Dave