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We concluded that the main issue was the force vector being too close to perpendicular to the guide. Therefore we create a guide design to minimize this occurrence:
We learned from our mistakes and verified that this design would not encounter any friction issues. After verifying this, we built the mechanism using 3D printed shafts and cranks with the slider being locked in with a long screw to fit ball bearings at the end of the screw which made contact with the slider. We attached the crank to a 360 continuous servo and our prototype was complete.
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