I to like crafty things but...... Files and rasps are cheaper than what you have in this project.
My work horse handle shaper is a 10" Nicholson half round course wood file, $19 with free shipping off several sites. I used my first one from day one of my bow building in 96, put it to metal a few times( not a good idea for a wood file) and replaced it just this year with a new one that cuts like a house on fire compared to my old dull one.
Of course I have the #49 and #50 pattermakers rasps which are pretty pricey but I also have a $12 horseshoe rasp that cuts like a demon as well a brand new in the pack Nicholson wood rasp I picked up at a flea market for $2.
What I am getting at is you are better off plunking down 5 more bucks for a good file or rasp that will outlast you, if you keep it clean, oil it if you store it for a while and keep it off metal.
A good file also gives you a place to use up some of that osage scrap we generate, in the form of file handles, gotta' love them.