Makita 4 1/2 inch Angle Grinder using Dewalt DW4772T Bit

Makita 4 1/2 inch Angle Grinder using Dewalt DW4772T Turbo Diamond Cup Wheel Bit for grinding thinset mortar from back of swimming pool tiles.
Problem is the Dewalt DW4772T bit is threaded and the Makita seating wouldn't seat properly. Using a Dremmel, I was able to remove the threads so the bit could seat properly in Makita Angle grinder.