Probably all is OK with that repair, but paint the nut and adjacent sprocket area (preferable something more visible than black), then if the paint is cracked the sprocket or nut has moved. Keep a sharp eye on it, like every time you check other nuts on the bike or retorque the heads. If you happen to catch any loosness before the sprocket is lost, a last resort on the road repair is weld the sprocket to the hub.

The biggest problem here is that the rear wheel on a rigid frame is not always in contact with the road, every time you go over a bump or pot hole, the wheel, chain and sprocket has lost the torque from the engine, no problem there but when the wheel is back on the road, that’s when the damage get done! Huge shock to the whole drive train system!

The way I see it, an engineer could get a new sprocket, separate the teeth from the spline (about half way) then weld two large washers, one on each side on the teeth part of the sprocket, locking the spline part in between the two washers, meaning the teeth would spin freely on the splined part, then cut some windows in the washers/splined section and cage tensioned springs in the windows! i hope someone understand my post!

Didn’t know it existed! That’ll be the way to go thought.