My Mora blades got dulled when a friend banged them on the ice to get the hole started......duh....! I resharpened them so they shaved fine hairs off my arm - but they wouldn't cut ice worth a d*mn until I shimmed the blades. I cut two pieces of galvanized tin about 1/4" x 1 1/2" from an old heating duct, and mounted one between the bolts of each blade, and got right back into drilling holes again.