Hand grip dynamometer.
https://diqn32j8nouaz.cloudfront.net...e_fullsize.jpg
https://diqn32j8nouaz.cloudfront.net...1_fullsize.jpg
Previously:
https://www.homemadetools.net/forum/...639#post228942
https://www.homemadetools.net/forum/...996#post221047
https://www.homemadetools.net/forum/...322#post188693
https://www.homemadetools.net/forum/...947#post213726
https://www.homemadetools.net/forum/...986#post224241
