pentaxpete
Hi All - hope you don't mind me advertising but I have done some Videos on You Tube and there is one on my M42 Screw PENTAXES including Spotmatic I and the Spotmatic F -- maybe you will watch ?
https://www.youtube.com/watch?v=-cNhZkpGf80
https://www.youtube.com/watch?v=-cNhZkpGf80