Cruiser, I thought you were converting this to a belt drive (which exerts a radial load from the motor/tool and belt tension). A gear is a bunch of levers extending out from the center. Unless the gear in question is an idler, it also has radial load exerted on it. A 40 deg. angular contact bearing is designed for mostly axial load (in one direction which is why they are normally used in opposed pairs) and partial radial load. I don't worry about anything, including your spindle, but maybe you should start. Anyway, I hope for the best, good luck dude.