Reply To: Cutting lap. Aluminum or Steel › Forums › Beginner Questions › Cutting lap. Aluminum or Steel › Reply To: Cutting lap. Aluminum or Steel December 26, 2019 at 9:56 pm #5967 FrankwoodParticipant @Frankwood The problem with the final cutting lap is runout. I like to use a dial gauge as a stop and having the disc bonded helps a lot. I know which way it has to go on the machine master lap to prevent dial gauge needle flutter.