Review on POWERTEC 13 Inch HSS Replacement Planer Blades for Ridgid Planer R4330, R4331, TP1300LS and AC20502 - Set of 3 Knives by Tony Jockheck

I installed them on my Ridgid R4331. Other reviewers have indicated that they had to file the grommets on the ends of the knives to fit, but that wasn't necessary for me. I was skeptical after reading the mixed reviews but the knives were needed quickly to complete the job. I ran 12 pieces of 1X4 American Cherry through the slicer, removing 1/64 inch (maybe less - ⅛ turn on the cutterhead handle) on each pass. By the third pass the boards were dull, like butter knives with a few prongs on them. Very disappointed as I now have to find another set of knives to complete the job. If you send pine or cedar, they can work for several days. However, if you use them on hardwood, expect them to last around 45 minutes.