A die cavity machined to the exact size and shape of the tube with only sufficient allowance for a slip fit with the tube. This allowance may be as little as only a couple thousandths of an inch on the diameter; therefore, tubing that significantly varies in its outside diameter will require the ideal true cavity specification to be compromised with additional allowance in order to ensure at least a slip fit. Compare nominal cavity.
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.