Last week I did a repair on the rear hub assembly. The locknut holding the rear axle mounting plate in place had come loose and needed to be replaced. So I did: bending back the two dents holding the nut in place and take it away. Replaced with a fresh nut and securing it by slamming two dents in the locking ring with a screwdriver. I know; this is not the way to do this. What tool is used to produce nice smooth dents in the locking nut?