Lucien Sharpe sheet metal gauge
circa 1850
Palmer's micrometer (replica)
circa 1848
early metric micrometer
1878
Micro 2000 electronic digital metric micrometer
circa 1980
digital readout micrometer
pat 1893.
Pocket micrometer
circa 1885
Brown and Sharpe 0" to 1" pocket micrometer caliper
1928