Gear slipping HELP!!

A while back I started to build a robotic arm for my senior project. Its finished now and I will post the pictures soon. However I ran into a HUGE problem today when I was testing it.

The shoulder gears were slipping so much that the arm couldn’t lift itself.

I’ve tried the following:

Switching out the standard gears for high strength gears
Adding supports/braces to restrict the loose axles (the 3rd gear axle has carved a hole in the metal)
Use rubber bands to improve meshing

I’m worried that I will have to move the entire shoulder section to fix this. The pictures should explain why:

Any ideas on how to solve this?

I have not worked too much with lifts, however, it is probably a good idea to support your axles on both sides. The cantilever axles causing friction is the main reason the axle has carved a hole in the metal. Also, I can’t tell if you used bearing flats or not with your axles, so if you did not, make sure you add them in.

This. With anything bigger than a clawbot (and arguably with a clawbot too) having double-supported shafts is a must, ideally as close to the load point (the gear) as possible

I would say to extend the shafts in the gears through the other side so that the shafts cannot bend and skip, this is from previous experience with gears like this. Also move the cortex down so the shafts can go through the over side.

First, like others stated you should support your drive shafts on both sides. I would double up your gear train to distribute the load by creating more surface contact and it will also reduce your gear slop. If you add a counter weight to the rear of the shoulder that creates a moment equal to the arm plus load, you will reduce the amount of torque needed from your shoulder motor, and reduce the overall tension on that joint.