maybe a working power gadget?

[Justabuyer]

http://mastergradeknifesharpener.com/

This thing looks like it will do convex. Anybody use one?

 

[Lucky Bob]

Looks like it might be interesting. Overkill, but interesting.

 

[siguy]

seems like a pneumatic sanding drum would work just as well, and be more adjustable to the grind.

 

[ColtM1911A1]

And yet, another gadget...me-oh-my...