Why does my skeletal mesh seem so unstable during simulation?

I’ve been trying to make a simple “flail” type weapon as a learning exercise but it behaves very erratically when simulated…

In contrast this dev seems to have a very stable flail physics..
I've tried setting the physics angular dampening ont he bodies but that doesn't seem to do anything.

What can i do to improve the stability of the simulation?

Edit: I’ve also tried turning off collision for all of the bodies.