# How to design a compact, low-center-of-gravity body for a 3–5 kg metal robot soccer chassis? Seeking advice

- Source: Reddit r/robotics
- Published: 2026-10-24T19:14:59.000Z
- RoboHot: https://robohot.news/en/items/suv31mxjk788v8obpmyn9836i
- Original: https://www.reddit.com/r/robotics/comments/1xeh7g7/help_designing_the_chassisbody_of_a_35kg_metal/

## Summary

A developer is converting a cardboard/wood prototype into a metal chassis for a 3 kg–5 kg class competitive mobile robot, planning to first use a single base plate to mount 300 RPM Johnson motors and BTS7960 drivers. Their core questions are: how a small 300 mm×300 mm-class metal robot can achieve a compact body and low center of gravity to hold off heavier opponents, and whether a 100% invertible robot should use a base plate + standoffs + top plate sandwich structure or a bent sheet-metal shell. They also want prototyping methods for converting the cardboard model into aluminum plate cutting and drilling dimensions to avoid mistakes on the first machining attempt.