Have you considered using a weak link in the line made from a smaller cross section string, such as monofilament fishing line? It's available in many sizes. The test strength is typically a bit under the actual strength but by how much varies by manufacturer. Knots reduce the strength, using a wrap around something with a reasonable radius keeps most of the strength and would keep things more consistent. The 3D printed weak link is a cool idea, but I suspect you may get some inconsistent annoying fatigue failures using the out of plane tensile strength of the material with such small section.

For quick power connect/disconnect, you might consider barrel connectors. There are wireable female and male versions of these.

You might get finer control of the breaking strength by using a smaller nozzle, like 0.2mm, which would double the number lines to needed to make the same diameter.

Soldering larger wires requires delivering power quickly to the weld. Lots of electronics soldering irons can't deliver sufficient heat flux. In that case, a mechanical connection is the way to go. Roughly in the order of increasing price for connecting stranded copper, your options include: (1) twist together; connect via a copper split bolt; wrap with electrical tape .. (2) crimp ring terminals or lugs; connect via a bolt or a bus bar .. (3) attach mechanical lugs; connect via a bolt or a bus bar .. (4) (for marine applications) apply Noalox; connect via an insulated multitap wire connector. All of this hardware can be purchased at an electrical supply store or an online industrial supply retailer. In the US, Grainger tends to be convenient. For reference, see the following path in their online catalog: Electrical > Electrical Connectors & Wiring Devices > Wire Connectors, Terminals & Terminal Blocks.

It reminds me of how Carlos Alcaraz or Roger Federer catch the ball with the racket. Sounds like that's what you were looking to do. It looks like they move to meet the ball and once they make contact, they quickly slow down. so you probably never have to be going faster than the ball, only be going the same speed as it makes contact.

XT-60 advice: you could try to compress the pins in the male side with plyers. There are slits in the pins that you can stick a screwdriver into to expand the pins if its to loose, and you can make them more loose by just compressing them

I'd be interested in seeing the physics simulation. I'll get over to Zulip and reach out. I've done some system modeling but have an interest in doing more of this. The compliant hand is definitely a cool thought, though the impedance of the hand is something to consider. If you can get the hand impedance (reflected linear inertia) close to the ball, then this would work great. Depending on the hand gear ratio, you may have quite a bit more inertia in the hand, and the ball will want to bounce off before it can accelerate the hand. Some damping will be very helpful in getting stable catches, I'm thinking bean bags vs rubber bouncy balls. It's a fun problem, perhaps a 1 DOF test stand to toss vertically would be helpful to test ideas. Assuming the hand impedance is low enough, then trying some ideas with controller gains to improve catching would be good. I think gain scheduling through the catch to the throw should be sufficient to avoid mode transition.

Instead of having beefy wires joined in a big harness, it would be more reliable and flexible to have a couple of bus bars, or bridged terminal blocks, with separate wires for each destination as well as the source

58:00 xt connectors are a little stiff, but should easily come apart by hand. That seems to be a cheap-choice problem.

Nice lash splice 😄 were you inspired by the NASA wiring guide? Since I’m a lazy electrician I probably would have just used a terminal strip.

maybe instead of movement compliance you can create friction to slow down the ball to catch it. what about some kind of funnel with a fabric surface? the funnel can be flexible or a bit springy so it has give as it enters and is also getting slowed down by the fabric friction. as it enters it gets tighter since it's a funnel shape. to throw you can relax the funnel and expose a harder rounded surface below like what you had before to throw it