"No one is looking, let's flip around 360 degrees!" how to generate clean subframe data from animated/deforming geometry

[Coz_y_not]

If you take Crag test geometry. Go to your global animation options, uncheck integer frame values (have the step at 0.1).

After Crag moves to grab the hammer,scrub the the timeline at every subframe (right arrow), be patient it's coming ... carry on, not yet, there, right there do you see it? geometry going crazy in between frames, not once many times, even the hammer takes the opportunity to flip around 360 degrees in between frames, coz why not? no one is looking, right? not really, the solvers can be a bit allergic to this "immature recalcitrance" in between frames.

 

What I've tried to do is first to kill the subframe data that came with Crag animation by default, coz it's trashy.

then attempted to recreate subframe data several ways for half a day (stealing the kitchenware from the deprecated timeblend sop), got some less than optimal results, then time to ask: how do I generate smooth subframe data? I mean as smooth as the original except some craziness in between frames?