Looks like an excellent design and should work well.

One suggestion. Use two razor blades instead of one and you can create a very shallow V that will help greatly to retain the axle in one place. Unbalanced props tend to walk the axle if it's not retained at least somewhat.

I also taped over the blades toward the ends. It's amazing the damage those things can do when held rigidly and pointing up where your hands are moving.