RD4B Gears

Currently, my team is making a RD4B with a 1:5 gear ration with 4 torque motors on the middle section. We’ve begun to notice some problems, such as how the top part of our RD4B can move up and down about an inch or two without the bottom of RD4B moving at all. We believe that this might be happening because our gearbox can easily shift around because there is nothing except for the axles used for the gears and a few onebys holding it together. However, we have no clear connection points between the two c-channels so our only option is using onebys and c-channels. Another possible reason this might be happening is because we tried to maximum height efficiency, meaning we added 2 36-tooth gears in between the 60 tooth gears. Which one of these problems are making half of our RD4B move up or down while the other part remains entirely stationary?

@Coffee Here is our arm tower.
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Judging from the photos you posted, I don’t think your “issue” is from the factors you mentioned. The reason that I put issue in quotations is because from what I can tell, what you’re seeing is that when you lift the front of the rd4b by hand, it takes an inch or two of movement before the bottom bar moves. (Please correct me if I’m wrong).

This should simply be slop resulting from all the joints in the lift and gears, meaning that the your top bars and their various joints can bend a little bit within their connections before engaging actual gear movement. This is kinda just due to the nature of multi-stage lifts and vex components. When the motors lift, you shouldn’t see this slop or a disjunction between the stages if its simply due to slop.

Like @Coffee said, using fewer gears will reduce the amount of rotation points/joints and thereby reduce “slop”, or mechanically linking your gears should work great without needing to redo your gearbox and whatnot, which you say you guys want to keep.