What is this?

[mmcmdl]

Is there a vernier scale on the other side ?

 

[DavidR8]

Is there a vernier scale on the other side ?

No, just what you see.
The repeating numbers are completely perplexing.
If the numbers didn’t repeat I’d say it’s metric.


Sent from my iPhone using Tapatalk

 

[hman]

What do you make of the odd numbering?

Earlier: "The graduations around the dial are very odd. 0, 5, 1, 1, 2, 2, 3, 3, 4, 4"
I think it's a metric micrometer. The numbers are likely 0, 5, 10, 15, 20, 25, 30, 35, 40 and 45. Half (0.50) millimeter per turn. The second digit of each number is covered by the big knob.

You can check this by holding the extending stem against a millimeter scale, rotating the knob a couple turns, and checking how far the stem moves on the scale.

 

[DavidR8]

Earlier: "The graduations around the dial are very odd. 0, 5, 1, 1, 2, 2, 3, 3, 4, 4"
I think it's a metric micrometer. The numbers are likely 0, 5, 10, 15, 20, 25, 30, 35, 40 and 45. Half (0.50) millimeter per turn. The second digit of each number is covered by the big knob.

I think you’re right!


Sent from my iPhone using Tapatalk

 

[mmcmdl]

The second digit of each number is covered by the big knob.

That would surely make sense ! Good catch .

 

[francist]

Brilliant! Yes I can see a hair of the second digit sticking out now that I look for it.

 

[DavidR8]

I can tell you that short of cutting a slot into the large diameter there is now no way that I would dare try to extract the micrometer part.


Sent from my iPhone using Tapatalk

 

[Mike_Mac]

Yes, it is metric. I suppose you do not see much metric 'stuff' over the other side of the pond.

 

[DavidR8]

Yes, it is metric. I suppose you do not see much metric 'stuff' over the other side of the pond.

I’m in Canada so I’m used to metric but I do all my machine work (and woodwork) using imperial measurements.
The previous owner of my house was a machinist and he left me a real cache of high quality tools.


Sent from my iPhone using Tapatalk

 

[extropic]

I can tell you that short of cutting a slot into the large diameter there is now no way that I would dare try to extract the micrometer part.


Sent from my iPhone using Tapatalk

I would expect that the custom ratchet stop/large knob would be easily removed (as the standard ratchet knob would be) by removing the slotted screw.
Or, is the large knob pressed (or bonded) to the micrometer sleeve and the ratchet stop is non-functional (removed?)?