July 10, 2021

Moog System 55 Replica Case - Bottom Chassis

This may be the most difficult project I’ve ever done. Cutting a taper on the side panels led to some complex calculations. To over-complicate things just a bit more, rabbet joints were once again added to the case. The original System 55’s front is completely planner at a 70° angle. This required that the top and bottom panels have a chamfer at the same angle as the sides. Lacking a table saw, the cuts had to be done on the circular saw, a tool I absolutely despise.

Cutting the taper on the side panels had to be done using brute-force math. Normally I would have traced the width of the top panel directly onto the side to mark the thinnest edge. Due to the chamfered top panel and Rabbet cuts this was impossible. Knowing the height on the bottom chassis from my CAD models, I subtracted off ⅜” from both the top and bottom to account for the rabbet cut. I then measured that distance on the stock and drew a line to mark a location for a miter cut.

System 55 bottom chassis glueing and clamping
System 55 bottom chassis glueing and clamping

Instead of trying to calculate the angle and depth of the chamfer cuts, I used a ruler to extend the angle of the side panel onto the top and bottom. The circular saw was then set to the same angle as the side panels and a miter gauge to set the depth. To my surprise this worked extremely well; on my first try! The Bottom panel chamfer was done with a hand planer and pencil lines. This was more fun to do, but wasn’t quite as efficient or square. If I do it again I will use the circular saw.

From this point on, construction was straightforward. Sand. Stain. Poly. The power system took a bit of time as the -12V channel required a slight boost from an auxiliary DC power supply. A capacitor bank in each chassis was added to smooth the DC voltage for an extra quiet system.

Overall I'm really pleased with the final product. This case took 16 hours of combined build and design time. For comparison, the 6Ux84HP Eurorack cases take about 4 hours.

Complete System 55 replica case
Complete System 55 replica case