For model #s 3850,4000,7000,7500,6900,6950----- Twin cutter / 9831 Grinding set----- Ammco part# 7681-6 FMC John Bean/Barrett # 91212----- RTI Models BRC500,BRC50-----3 cut edges---positive rake 500 series on the car lathe 6 bits per pack. California Residents WARNING
