World’s Oldest Micrometer – 1776! Who made this thing??

After months of communicating with Ben Russell, the mechanical engineering curator at the Science Museum, London, I finally visited and we took a very close look at the micrometer reputedly made by James Watt.



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  2. stephen bennis

    I can see what could be where washers sat for the base mount, a faint outline(10:18). Or maybe wishful thinking.

  3. Ed Vojcak

    Most likely made by Watt – we must remember that a micrometer did not exist and Watt was thinking on how to make an instrument to measure distance for a specific reason – there were no rules only some general ideas on how to build instruments -refinement came a lot later. There is a similar problem in mathematical proofs – the original proofs had errors that were corrected – just as it been said (I think by Gauss) we see the Cathedral as-built not the scaffolding used to build it.

    BTW thanks for the references.

  4. Antony Hall

    Just reading Simon Winchester’s book ‘Exactly’ ,’How Precision Engineers Created The Modern World’ , if you are interested in engineering and technology, you should be interested in its history. This is a very readable introduction to the evolution of our quest for Precision and Accuracy. While reading the pages on Whitworth’s micrometers I discovered Fascinating, many thanks for the info, I will be back for more.

  5. Todd Barrett

    Don’t you think the marks one the back are from inserting and removing the pins? Using a hammer on soft brass would make marks like that.

  6. Todd Barrett

    Also the “knurling” on the edge could have been used to index the graduations.

  7. Don Schlosser

    What were the screw diameters and thread sizes? Standardization only started to occur after about 1800. If the screws are not standard, are they sizes known to have been used by Watt? Also, XRF(non-destructive) could be used to determine the compositions of the various metals, which would help in dating the instrument.


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