https://www.ebay.co.uk/itm/124807386440?...SwGUxg4baf
The first one that came up - obviously choose sizing to suit what you plan to measure, this is a bit OTT for an A7.
n.b. with the caveat that these things tend to be sold on when either worn out or a bit has been lost... it's a good idea to make reference measurements on something of precise known size to check accuracy. In industry special calibration blocks are kept specifically for the purpose.
n.b. 2 even when you have the right kit there's a definite art to using them... Really nice micrometers have a 'clutch' which helps you judge the right level of tightness.
The first one that came up - obviously choose sizing to suit what you plan to measure, this is a bit OTT for an A7.
n.b. with the caveat that these things tend to be sold on when either worn out or a bit has been lost... it's a good idea to make reference measurements on something of precise known size to check accuracy. In industry special calibration blocks are kept specifically for the purpose.
n.b. 2 even when you have the right kit there's a definite art to using them... Really nice micrometers have a 'clutch' which helps you judge the right level of tightness.