Lapis Lignum's video: angle grinder thin disc cutting speed and wear comparison makita flexovit pferd

Quick video showing cutting speeds and wear* of 6 types of thin cutting disc. Each disc made one cut through 16mm square mild steel. This video is not sponsored, I bought each wheel at the usual places. *Rank based on measured cutting time listed below time codes* 3:31 condition of each wheel after cut with cut time, thickness and wear % 3:51 no load speed measurement of angle grinder 4:03 special bonus footage of old used thick cutting wheel cutting same material. Rank based on quickest cutting time: Disc: Flexovit Reinforced Metal Cutting Wheel Steel & stainless P/N 66252919966 Cutting time: 12.28 seconds Reduction in diameter from wear: 0.91%* Measured thickness: 1.2mm Cost at time of filming: $2.58 Disc: Flexovit Maxx Cut Off Wheel P/N 66252841589 Cutting time: 12.28 seconds Reduction in diameter from wear: 1.06%* Measured thickness: 1.2mm Cost at time of filming: $2.70 Disc: PFERD Stainless cut off disc SG-ELASTIC P/N 61340412 Cutting time: 13.56 seconds Reduction in diameter from wear: 0.44%* Measured thickness: 1.2mm Cost at time of filming: $2.40 Disc: Flexovit Ion Cordless Reinforced Cut Off Wheel P/N 66253370632 Cutting time: 13.92 seconds Reduction in diameter from wear: 0.22%* Measured thickness: 1.2mm Cost at time of filming: $2.95 Disc: Makita reinforced cut off wheel stainless/metal P/N D-20529 Cutting time: 16.56 seconds Reduction in diameter from wear: 0.64%* Measured thickness: 1.3mm Cost at time of filming: $1.98 Disc: Flexovit Multi Material Reinforced Cut Off Wheel P/N 66253370635 Cutting time: 33.28 seconds Reduction in diameter from wear: 3.22%* Measured thickness: 1.2mm Cost at time of filming: $1.98 *while this is not in any way an exhaustive test it tests wear more poorly than cutting speed due to the low wear from one cut and measurement error. More testing with multiple cuts across multiple discs would be required to get an idea of the wear characteristics of different cutting discs. A better test would measure disc speed and grinder current, a better jig would use closed loop force control based on a set limit of disc speed or current. Real world testing would probably be better again. To the eye cut quality was equal for all thin discs. The only recommendation I'll make based on this limited data is to use a disc designed for cutting steel to cut steel. The jig ensures some level of cut direction consistency, cutting pressure was controlled by hand to stop the grinder bogging down excessively. Grinder size: 115mm Measured grinder no load speed: ~10,000 RPM Stated grinder power: 600 Watts Steel Stock: 16mm X 16mm square black mild steel.