The Bearing Launcher uses a magnet and some neat physics to fire a steel bearing. It can fire three consecutive shots and features a manually-operated self-aligning three-chambered, revolving ejector (or MOSATCRE) for easily retrieving the "trigger" bearing from the barrel after each shot.
VIDEO LINK: http://www.youtube.com/watch?v=MdWo_VIjpug
Skein with 1 extra shell (2 shells total) & 10-15% infill for ideal friction-fit of all components. If your Z-axis is not calibrated correctly you'll need to shave off the flared or "squished" first few layers on all inside circumferences to ensure proper fit of rods and magnets.
Before you start: stack all six magnets together. Pick an end and use a sharpie to mark the "top" of each magnet so you can make sure their polarities are properly aligned in subsequent steps.
Cut two 8" lengths of 1/4 inch aluminum rod & sand/file all ends.
Press fit one M3 nut into Part2.
- Stack the five small magnets together and press fit the first two into the two small holes in Part4. It is critical that their polarities are oriented in the same direction.
TIP: Get one started, and then flip Part4 over and press it against a flat surface to seat the magnet. Stick a second magnet to the seated magnet, then slide it over to the second hole, get it started with your finger, then flip it over and seat it against your flat surface.
- Stick two magnets to the now seated magnets in Part4. Align two of the small holes in Part3 with these magnets and press gently to seat both at the same time. Repeat this process with the final (fifth) small magnet.
TIP: Part3 should now stick to Part4 by any two of its three arms.
Thread the M3 bolt through Part4, starting from the side opposite the small magnets, until the head is flush.
Drop Part3 onto the bolt, making sure magnets on both parts face each-other. It should turn freely and "snap" into position when magnets align.
- Thread the bolt into the back of Part2 and into the M3 nut.
TIP: The end of the bolt should be flush with the nut and Part3 should be able to turn freely between Part2 and Part4.
- Press the big magnet into Part2. It is critical that the big magnet's polarity is opposed to the small magnets in Part3.
TIP: Place the big magnet against one of Part3's arms (side opposite magnets) and orient it so it is repelled away from Part3. Maintain this orientation as you press in into place. It will not fit as snuggly (yet) as the small magnets did.
5 printed parts (1 each)
1/2â€dia. Stainless Steel Ball Bearing x 5
1/2â€dia. x 1/4â€ thick neodymium magnet x 1
1/8â€dia. x 1/8â€ thick neodymium magnet x 5
M3x33mm bolt x 1
M3 nut x 1
1/4â€dia. x 8" long aluminum rod x 2
Magnets & bearings available from Amazon here:
Engine driven, fully-automated, rapid-fire, bearings of zombie-death. I'm talkin' Old Painless. Make it so . . .
Designed by C.Boynton