Collapsable Tennis Ball Thrower - Now With Magnets!

When you have a dog that loves playing ball, a thrower helps save your shoulder and keeps you from handling drooly gross tennis balls.

But carrying a 2 foot long thrower can be awkward. So I designed a collapsing thrower, so that it's easier to get to and from the park.

It works quite well, my dog loves it.
 

Tennis balls work best, but it's compatible with any tennis ball sized balls (ChuckIt, Nerf, etc).

When extended it's about 2 feet long. When collapsed it's about 9 inches long.

Parts Needed:

It's designed to use M3 bolts and M3 heat press inserts. Alternatively you can use an M3 bolt and nut or it's 1/8" imperial equivalent. 

It can also be glued instead of using bolts, but that makes it so parts are not replaceable when they break.

Magnets can be whatever you want. I use round magnets with holes in the middle. One 12mm, one 25mm.

Printing Instructions:

Both PLA and PETG work well, PETG works slightly better. I recommend making the seams random, that'll make the tubes fit and slide more easily with less post-processing.

The grip and end cap can easily printed together, as the same settings are recommended. Same with the tubes and tip.

Starting at the bottom: 

End cap -  No supports should be needed. Print with the bottom on the bottom. Has a hump in the middle for a heat press insert so to make adding a magnet easy!

Grip - No supports are required. Print with the threaded end (bottom) on the bottom.

Tubes - No supports. The tubes are numbered from the widest to the narrowest, 1 being the widest. Tube number 1 is thicker than the other tubes, as during testing it broke.  The file is for 4 sections, but they can be separated and printed individually if you have a break. Print with the numbered end at the bottom. I recommend an outside brim for all of these.

Tip - More solid than the tubes, and has a hole through it for the bolt/heat press insert, as well as a hole at the bottom for a magnet.  Print wide end at the bottom, outside brim recommended. I find 15% infill is fine, I prefer gyroid.

Head - The most complex bit. Best in PETG. I use 4 walls. Requires supports. Best orientation I have found is pictured.