[shimarikakari]

If your robot exceeds the weight limit, I'd say that making swiss cheese of the chassis will only add to the trouble. I'd recommend making the frames simpler for each of the devices on the robot. For example, we built a loader that weighed about 18 pounds because of the metal frame we'd constructed around it to make it stable. Then we realized that we didn't need the half of the frame on the inside of the robot, because that part was already well-supported. We replaced the inside half of the frame with two tiny bits of metal connecting the front and back halves of the loader. Now the loader weighs 9.5 pounds (and dropping). We estimated that, because of the particular brand of metal we're using (80/20), we could only have saved a couple of pounds with the swiss-cheese strategy. So, I think it's more important to design the robot right than to drill it at the end.