david weaver
I haven't planed much locust, just a little bit. It lasts for eons in the ground, and it makes the chainsaw spark (we burned a lot of it) sometimes.

If wood makes a chainsaw spark when you cut it, it's bad!!

Janka measures a dent if I remember correctly. There should be another measure that provides the hardest constituent part of wood, also , as it's not a complete measure for harshness on tools. It's a good start, but indian rosewood is supposedly much harder and so is gabon ebony, and they both plane wonderfully (gabon ebony doesn't have a lot of directional conviction, and fractures a lot, but it's pleasant to plane through).

I fell into the trap of thinking that my tool kit and irons should be set up to deal with those woods, even though I knew they'd only be a small percentage of what I work with in the long term. Understanding ideal weight for tools, etc, cooled my jets about making planes from rosewood, etc, too. Nobody wants a 28" rosewood jointer that's full height and width unless it's going to sit on a shelf "look at this plane...it's 17 pounds!! it'll go through anything!!" (including users).