joinmax elbow mod

out of all the parts on the robot the one that i was the most worried about was the yaw joint for the hip. the servo mid-arm just twisted too much for my comfort. worse, it had the the entire leg for leverage against it.

i was looking at the joint and i realized that with a slight modification i could combine two elbow brackets at right angles with only a 3mm extra offset for the degree of freedom.

here is how the joint was originally held together. that little arm was the problem. (sorry for the shit pics, i need more ambient light. the flash drowns it)

the next pic shows the mod. i used a utility knife, but the dremel i don't have would of worked better.

the next pic shows the new joint (top) and the old joint (bottom). the torsion is totally gone and the only play is in the servo gears themselves. i think that play will go away when powered too. now i just need to find a longer self-taping screw.

btw. he currently weighs in at 16oz. the servos have 50oz/in of torque, so maybe it'll even be enough in reality vs my-gut-thinks-it'll-work world. add a battery and electronics.. maybe not.. however, i can test with that stuff wired and sitting beside him. lipoly batteries are light right? if it turns out to be too much with everything on board i can always do a rebuild. the rebuild won't use store bought servos. i'm going to build them myself so they will be way more powerful than i need. i'll probably make him twice as big too.

btw2. whoever designed the form factor for these joinmax servos and joints is brilliant. you have an incredible number of options in mounting things together. (even if you do need to do a little cutting some times.)