3 replies to this topic

[stuck by stefan]

Sharing what I've been working on the past few days. This is my TornadoBow. It uses the same design as pretty much all of them, except the plunger tube supports, trigger, catch, and spring plate are 3D printed. I've uploaded the files here for anyone who wants to recreate this. The plunger support plates are a friction fit, and shouldn't require much adhesive. The catch is designed for 1/2" Nylon rod. https://www.thingive...m/thing:2775832




 

I've also developed what I hope will be a solution to the problem of broken priming handles everyone's been having. Rather than a simple nub that attaches to the handle and creates a point where the handle will flex and snap, I cut a piece of poly that fills the entire void of the priming handle and distributes the load. It's also a friction fit, and I haven't had to use any adhesive to attach it.

Edited by stuck by stefan, 30 January 2018 - 03:54 PM.

[TantumBull]

Just look at your faith in printing grow! I wonder if you couldn't get that remaining polycarb piece (priming handle reinforcement) to be printed as well. If you took the same dimensions of the piece you machined and added sufficiently large fillets to both internal corners (and made mating fillets on the plunger rod slot and yellow handle) I bet you would be good to go. I know that piece is thin, but most of the load should be down the length of it, and the largest stresses will occur at those 2 internal corners, hence fillets. Probably wouldn't hurt to fillet the outer corners as well but those needn't be as large and likely won't be points of failure.

 

Overall good work man.

[stuck by stefan]

Just look at your faith in printing grow! I wonder if you couldn't get that remaining polycarb piece (priming handle reinforcement) to be printed as well. If you took the same dimensions of the piece you machined and added sufficiently large fillets to both internal corners (and made mating fillets on the plunger rod slot and yellow handle) I bet you would be good to go. I know that piece is thin, but most of the load should be down the length of it, and the largest stresses will occur at those 2 internal corners, hence fillets. Probably wouldn't hurt to fillet the outer corners as well but those needn't be as large and likely won't be points of failure.

 

Overall good work man.

Thanks my dude.

Honestly that piece could probably be easily printed, I've been surprised at the strength I've been able to get with solid infill. But since I'm planning on epoxy-ing the part in place, I wanted something that I knew wouldn't break down the line. If my priming handle does end up breaking I'm gonna try entirely 3D printing one, although that might be problematic.

[Maniacal Coyote]

After using The Morrigan in war, my $0.02 is that you could 3d print the plunger rod as well, if you have a large enough print area.