Case Study: Drill Driver Gearbox

Process: Conventional powder metallurgy
Secondary Process: Machining and milling
Hardness: 62 HRA
Density: 6.9 g/cm³

End Use and Function

This part is composed of five components comprising an output gearbox that serves as feedback for an anti-twist lock on a drill driver. This part contains extremely thin sections with highly complex geometries.

2015 Award of Distinction: Gear Box Drill Driver
2015 Award of Distinction: Gear Box Drill Driver


The parts intermediate flange, anti-twist lock, mount ring, centering sleeve, and planet gears are made from diffusion-alloyed steel. The flange is compacted using two upper and two lower punches, and powder moving technology is employed to achieve a more uniform density distribution. Tight tolerances at the inner and outer diameters is accomplished through machining, and a milling operation provides the holes needed for part assembly. Properties include a density of 6.9 g/cm³ and minimum case hardness of 62 HRA. The parts’ design, with extremely thin sections and highly complicated geometries, required precise control by a CNC compacting press.


The PM design saved more than 40% over the cost of manufacturing through forging and machining.