Thanks everyone for your responses to my original query. I posted the original almost a year ago. The individual asking for help was looking for a way to hold a tool to put screws in wood. Specifically, a birdhouse project with his child/grandchild. We settled on using a T-handle, ratcheting screwdriver available at Harbor Freight. Needless to say there’s a lot of context associated with the assembly: positioning the work piece, selecting and orienting the screw (the tool has a magnetic tip so it can aid in bringing the screw to the work piece), holding the screw driver, applying torque, reversing direction as necessary. then repeating the process with the next screw.
Doing this right – i.e., taking the entire process into account – is a huge, and often custom, effort. I tried to leverage a bit of technology that I’d already developed – a customizable palm loop with a couple of defined physical interfaces. The quality of those definitions is up for debate.
What we settled on was the design at the bottom of the web page I indicated earlier. I printed it in TPU so it would be easier on his skin, flexible, indestructible, and provide some grip.