what is this for

attempt 2:

The pillars are probably for suspending the item to be measured between the micrometer anvils, to keep heat from the fingers away from it. When working in the tenths of a thou world, temp control is important for accuracy. See wikipedia for "thermal expansion of metals". Delta T is key, as one old measuring technician in the toolroom where I started work used to say, often......

Is the item on the left spring loaded? If it is and the index mark moves it could ne for measuring thickness of a elastomeric material under a pre-defined load.

Robert G8RPI.

Lightning conductors !

Dave W

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That makes it a 'fiducial micrometer'

Bedtime reading here, courtesy of NPL : **LINK**

http://resource.npl.co.uk/docs/science_technology/dimensional/moy-scmi/moy-scmi-22-print.pdf

MichaelG.

I have a floating carriage Micrometer with a fiducial setup very similar to the one above, I inherited it from my granddad, I've never used it, Ill dig it out of its storage box and take some pics if anyone interested.

Shaun

The black barrel on the left is spring-loaded, with a simple moving pointer that lines up with a fixed pointer to provide a repeatable force. I don't think the movement is necessarily enough to accommodate particularly elastic material. On the end of this barrel, it does say 'made to NPL design', so yes it is as per the specification from Robert above.

I don't think the posts are to suspend the work as they are not central, both are 'behind' the barrel for right-hand use. Lightning conductors seems more likely, I will try outside with a calibration piece next time we have a thunderstorm.

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... Thanks

MichaelG.