Gundrilling Machine Improves Heat Dissipation

The DeHoff 218 four-spindle special is a custom-designed gundrilling machine for producing hollow stem engine valves.

The DeHoff 218 four-spindle special is a custom-designed gundrilling machine for producing hollow stem engine valves. Several domestic and international companies have utilized the machine to manufacture valves for use in high-performance engines. A small-diameter hole is gundrilled in the stem of the engine valve and is then filled with sodium to improve the valve’s heat transfer capabilities during the combustion cycle. This enables engines to achieve higher levels of fuel mileage and/or horsepower.

The machine has a 0.25-inch (6.4-mm) drilling capacity and an 18-inch (457-mm) drilling depth. It features four drilling spindles on a single machine base and uses precision chucks and workpiece counter-rotation. The machine also features a magazine loader and servo-driven gantry automation system.

The DeHoff 218 features a durable, heavy-duty design that incorporates a cast iron drill head base with hardened and ground steel boxways, plus hand-scraped and fitted saddle, gibs, and straps (versus linear guideways and milled surfaces). Standard elements are also included on the machine, such as a high-pressure coolant system, Beckhoff controls, and a full machine enclosure.