I made a few key improvements to the bearing launcher/gun tonight:
Added a ramp to guide the balls to the front of the launcher
Switched to a slightly (1/32″) larger brass tube
Filed a groove into the trigger for the rubber band to rest in
These changes dramatically increased the reliability of the launcher. I recorded a couple videos, one just showing the new features and another showing a “fast as you can pull the trigger” speed test.
Ok, I’m taking a little break from the steam engine project. After getting the piston and valve made, it became apparent the precision I’m capable of with my Dremel and drill press are not sufficient for the rigors of rapid cyclic motion (as suspected from the start).
While I think more about that, I am working on a wooden arcade game that challenges the player to drop or launch .50 ball bearings down a slope to hit targets. The game will be fully enclosed (to prevent removal of the ball bearings) and will feature a pistol-grip ball launcher/gun as the input mechanism.
Below is a video demonstration of the prototype launcher. The brass receiver tube (the internal magazine) is so closely matched to the .50 balls they occasionally jam in there, so I’m looking into remedies for that. But you can see how the device drops out one ball while retaining the others until the player releases and pulls the trigger again. Ultimately, a supply of balls from within the game itself will replenish that brass tube as the player launches balls, since the tube only holds four.
I’ll post more details about how this works if the project looks ultimately feasible.