The meArm is awesome, but it has a major design flaw in that the entire arm essentially sits on the axis of the hip servo, which is just not very stable and puts a lot of strain on the servo.
This improved base remedies these issues and securely sits the arm on a base with bearings. Instead of using commercial thrust bearings or balls, the bearings are actually incorporated into the mount plate and are printed.
In order to improve the attachment of the servo to the mount plate, I also revised the mounting bracket to be more robust (use for the base and the hip and shoulder servos).
To add some candy, I included some branded side panels as well:) The make the branding stick out, change filament at layer 30 (if printing 0.1mm)
I print these with a brim to reduce warping, but it requires some cleanup after as the fit with the various other meArm parts is (be design) tight.
Attach the SG90 type servo (use metal servos) to the bottom plate using the servo bracket. The servo should be oriented to have the axis in the center of the bottom plate pointing into the "bowl".
Plate the mount plate into the bottom plate "bowl" with the nubs facing into the groove. Secure the mount plate to servo with a servo horn. The mount plate replaces the standard meArm mount/base plate.
See the 'bottom plate with bearings - assembled.3mf" for a visual guide.
Another assembly notes:
1.) first place the servos and servo arm actuators into side panels following standard meArm instructions. '
2.) attach rails on one side panel on both sides.
3.) attach shoulder plate to the rails
4.) attach this construct to the mount plate. This is a little tricky. Slide in the side panel onto to mounting tabs at a slight tilt to accommodate to bottom tabs of the should plate. Seat the side panel and at the same time, seat the shoulder plate into the mount plate. It should snap in satisfyingly :)
5.) attach remaining side panel to the mount plate and rails.
I wish I would have shot a video of it :(