a relatively thick - bodied doctor blade made of a low friction plastic material includes a seal relief bevel of between approximately 5 and 10 degrees . the blade then tapers to a tip support shape and tip of between approximately 0 . 001 and 0 . 005 inch . when used in conjunction with a chamber type inking system , the doctor blade cooperates with the chamber end seals to form a more positive and controlled seal therebetween .