Custom Shop-Built Electric Coffee Grinder – Engineering a Precise Grind

Engineers depend on coffee. In our studio we have a diner‑style machine that pumps out gallons of warm, bitter coffee—an essential energy source that has powered projects from the Osborne computer to modern Hatch‑Baby series. Yet, as coffee lovers, we demand better quality. I keep an electric kettle and Chemex at my desk for daily brew. Coffee grinder design wasn’t my first choice, but here’s why I built one.

I grind beans fresh for every brew, and for years I relied on a Porlex hand grinder. With increasing demand at Studiored, hand‑grinding multiple pots daily became time‑consuming. An electric grinder seemed obvious, but as an engineer I wanted a custom solution using the materials and tools at my disposal.

After work one evening I entered the workshop to turn this idea into reality. I sourced high‑quality parts from trusted suppliers to create a robust electric conversion of the simple manual grinder.

First, I addressed the coupling of the gear motor to the grinder’s shaft. Porlex’s pentagon‑shaped shaft protects against accidental drilling, but I used a lathe and file to drill a matching pentagonal bore, demonstrating that even idiot‑proof designs can be improved.

The remaining assembly was straightforward: I used IGUS track and aluminum tubing to align the 100 RPM gear motor with the grinder, which is secured with a single PEM thumb screw for easy removal. A gas spring lifts the motor during hopper filling, and a large stainless‑steel button provides on/off control. The 100 RPM motor delivers human‑like grinding speed with sufficient torque for any bean or grind size. It’s not silent, but the deep rumble signals a fresh batch to anyone within 100 ft.

Watch the grinder in action below.

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