A pattern of small diamond-shaped points cut into the surface of a clamp die or a clamp insert to increase its grip; the knurled points bite into the tubing material, thereby improving the clamps hold upon the tube. Knurling is functionally the same as serrations and carbide impregnation, but is not generally preferred. The points wear rapidly in comparison and cut the surface of the tube, which can exacerbate fatigue or corrosion of the end product.
FREE Tube-Bending Guide Download:
A complete guide to the principles of the 4-Step set-up for tube-bending tools
This is a printable handbook showing how to implement in four standardized steps the “forward mandrel” set-up for rotary-draw tube-bending machines and establish process control over the so-called black art. The procedure is based upon the guiding principle that the tools make the bend and takes advantage of the inserted design of modern mandrel tooling.