Officials at Northfield Precision Instrument Corp., a leader in the design and manufacture of precision workholding chucks, introduce the Model DPH-800 double diaphragm chuck. On this custom-made chuck, the client had to grip on two different diameters (top and bottom). You can see two sets of jaws in the picture. The part was exceptionally long so Northfield had to manufacture the body out of a 220 lb slug about 10" in diameter and 11" in length. This chuck was extremely accurate, only running out about 1µ (on diameter) along the entire length of the chuck, which was more than 15". The end user had to perform a grinding operation on the inside tapered bore of this part (a drive axel for a Volvo truck). This chuck also was designed with an air-detect feature so the machine will know when the part is properly placed in the chuck.

Northfield Precision designs and manufactures the world’s most accurate air chucks for any lathe, boring machine, grinder or VMC. Models include through-hole, high-speed and quick-change. Chucks are available in SAE or metric, in sizes from 3” (76mm) to 18” (457mm). Accuracies of 0.001” to 0.00001” (0.254m) are guaranteed. Custom workholding chucks and jaws are available, and free engineering assistance is offered.