Laser cut ninja toy
by zachr, published
Made this for my 7 year old brother. He wanted a "ninja star where the blades pop out". It has a really nice action. If you actually wanted to throw it, you might make it out of Delrin which is less brittle than acrylic.
I cut the parts out of .1" acrylic. I glued the "x" shaped handles onto the two large disks with a little acetone. I put two layers of packing tape on the small round spacer so that the blades had a little more clearance. The pins are pieces of 3/32 welding rod I had laying around. I just cut them to size and press fit them into the holes on the blades. I found that the laser tapers the holes a little, so it is easier to push the rod through starting from the wider side of the holes. Each blade has two pins, one protruding from each side of the blade (check out the images and video for more clarity). Everything is held together using a 3/4" 6-32 nut and bolt. You could lock-tight it, but I have mine just finger tight and it stays together. Check out the video of it working:
It makes a great desk gadget!