Tired of acting like a three handed monkey when changing lathe chucks, I combined the needs of my metalworking lathe's 4” [102mm]- four jaw and the 3” [72mm]- three jaw types into one positioner. Now it’s safe and easy to attach either of them with the rear screws at just the right height to slip into the spindle plate holes without fear of mishap.
Step 1: Two Sizes, One Fixture
Made from scrap 2X [38mm] thick pine wood, I sawed out their profiles after making a cardboard template that matched the height and curvature of the lower portion on each chuck.
Step 2: Gettin' Groovy
The base was double grooved to allow the fixture to span over the lathe bed's prism, that triangular hump that guides the carriage, when rotated for either profile.
Step 3: Parting Thoughts
It is an unpardonable act to drop your chuck on the lathe bed while installing or removing it. Impact marks on the lathe ways are a permanent sign of carelessness; always put something down- a scrap board at least, to protect those high precision surfaces when performing this task.