Saturday, May 11, 2013

Toilet brush machine gun: Getting closer

Worked some more on the weapon today. Added a nice front handle, Moorhammer style. Banded all four forks up.

I quickly encountered a huge problem: Return to senders and misfirings!

Those returners are dangerous. I mean seriously dangerous. One hit the door right next to my head... two inches to the right and I'd be in trouble now.

I don't really know what is going on - what I found out is that it works as long as you turn really slow. The fast spinning action of the battery drill is probably too much, destabilizes the "bolts" in flight.

I attached thin rubber bands to at least avoid the return to senders - this works fine. But there is still the issue of the tumbling bolts. About half of them do that. It must have something to do with the rotation - no problems at all if I turn by hand and push the bands up one at a time.

If all else fails, I will convert this baby to manual repeating action.

But it does look cool!


  1. The tumbling comes from the bolt being drawn sideways by the rotating fork so you might try to modify the drill so it does a kind of stuttering rotation (using a relay or something) stopping every time a bolt is fired and then continues. Might be hard to time correctly but with a bit of 'slow-mo-analysis' it could probably be done ;)

  2. Since I havn't seen it being fired I have to guess a little bit. When fired the ball goes in a strait line but the fork moves to the right ( clockwise). During the time it takes for the ball to come to the fork, the left forktip has moved in the way of the ball. I think that the narrow fork is the greatest problem. It also be the ball hitting the rubber bands. Filming in slomotion can give some ideeas of the problem.

    If the release slot was facing to your right instead of up the amount of power for releasing the shot would bee lesser. The shot can also bee releast a lttle bit erlier to awoid hitting the fork, that howewer demands a given rotation speed.

    Is moving the rubberbands one step an option? Instead of a narrow fork is it pooible to use the gap between two forks. Using the the right forktip on one fork and the left forktip on the next fork. That includes moving the release plate 45 deegrees so its in line with the bands.

  3. Thanks for sharing such a useful post.