How to weld a frame without an expensive welding table

For my senior design project, I am working on a hybrid go-kart that leverages both a gas-powered engine and an electric motor to provide high torque at low speeds and very high top speed. To showcase our powertrain at demo day, we obviously need a strong chassis to mount everything for driving.

To build this chassis, we need a way to cheaply align all the cut frame rails and weld them together with enough accuracy that we don’t need to gap any welds when cutting the frame rails to length directly from the SolidWorks cut list. Professional shops accomplish this using large, expensive welding tables with precise hole patterns that allow frame rails to be bolted down in exact positions during welding.

For our project, we don’t have access to such a table, so we are going to build our own. We plan to use laser-cut wood to align everything with high precision. Then, we can bolt down 3D-printed jigs to secure the pipes during welding.

How does this relate to M5? At M5, Robert and I have been designing and building a 600-pound boombox, powered by twin 2.5-horsepower electric motors to move two massive JBL speakers and an audio equipment rack—enough to terrify the residents of downtown Amherst with loud music.

To build the frame for the boombox, I will be using a similar alignment strategy to match the design in FreeCAD. However, I don’t need a perfectly flat surface, so instead I will 3D print alignment jigs to square the corners, and then slot in the cut segments that I fabricate at the makerspace.

Karl Kreuze

Electrical Engineering, 2026, Computer Engineering, 2026

9 March 2026

https://www.umassamherstm5.org/blog/pyl6dlnzjs50zwhfwq2834vqqmwxxd