Primitive Archer

Not sure what you mean by "fire hardening".  Heat-treating is essentially the fire hardening of wood.  If not done properly though "heat-treating" can be nothing more than changing the surface wood's structure and that really does nothing for a bow.  Proper heat-treating of a bow is a process that takes several hours to do.  Osage and BL certainly benefit from heat-treating but they react a bit differently to heat and you have to keep a close watch on what's happening with the wood, I suspect it may have something to do with the oils in the wood

"Fire Hardened"
Just using the terminology many have used online to describe the process of hanging a bow over a bed of coals and baking the belly of the bow (usually a white wood) pretty substantially. I guess it is just another form of heat treating?  I will defer to you Marc, you have learned and tested more with heat treating than most everyone here combined.
My original curiosity was more about whether Osage benefitted from doing the same type of heat treating/fire hardening as is done with hickory - as an example.  Sounds like it can - but needs to be done more carefully than other woods if I'm understanding correctly?

Thanks y’all! Appreciate the help! I was getting in my head about whether I was close or not 

The sled

Here is a picture of my splitting stand. I didn’t like bending over all day working on them.  I would split them into chunks small enough to handle right after cutting.  I sealed the ends multiple times with glue or polyurethane. I would leave them stacked in my garage and split them down into staves when I had time. I would recommend removing the bark and sapwood while it’s fresh.  It gets much tougher once it dries. Seal the backs a couple times as well.  If you leave the bark on you risk borer damage.  I made a log sled to pull behind my UTV.  It made them slide over the ground much easier. 

Not sure what you mean by "fire hardening".  Heat-treating is essentially the fire hardening of wood.  If not done properly though "heat-treating" can be nothing more than changing the surface wood's structure and that really does nothing for a bow.  Proper heat-treating of a bow is a process that takes several hours to do.  Osage and BL certainly benefit from heat-treating but they react a bit differently to heat and you have to keep a close watch on what's happening with the wood, I suspect it may have something to do with the oils in the wood