Bought these to cut some sheets of plywood for my theater seats. The 3/8 inch bit started a rough cut after 6 linear feet and a bad walnut base on the third tray. In all, it cut 8 linear feet at 25,000 rpm in three separate sessions before becoming a fire hazard. at slower speeds, but at 16,000 rpm there was a rough cut that required a lot of grinding. See photo for 5/8" dowel insert sizing.