[Andrew Schreiber]

The thing would have stopped running. I've done this kind of prototyping for nearly a decade now and never had anyone hurt by a drill "popping off". In fact, using a system with a clutch and that loses power if someone drops it is significantly safer than using a motor with connectors into a battery or with exposed leads as I see quite frequently. Additionally all the gears are encased in a nice plastic shell so they can't catch fingers. Honestly, for prototypes drills are a pretty nice way to test. They have variable speeds, stop really quick, and have a clutch so you probably won't destroy your mechanism if it hits a hard stop. It also probably won't destroy a person if your mechanism hits them before you let go of the trigger.

2415, thanks for sharing. We have a couple roller claw prototypes out of Vex parts but I think I might get busy with a router and some plywood tonight to see if the shape of the back has a large impact.

A few questions:

What is your compression? You say you are compressing to less than 5" thickness. Does the drill seem to be struggling at all?

Have you tried other widths? 5", 7", 9"? Did this have an impact?

Have you tried not having rollers in the middle and instead grabbing from two points on the side?

Have you tried pulling your tubes out by hand both while the motors are running and while they aren't? Perhaps use a cable tied to the piece with a force gauge to measure your grip strength.

Have you tried grabbing at an angle? Both relative to the floor and relative to the tube.