I have a little present for you ready to download. You should be abble to build the shoulder with succes if you follow the tutorial I am going to post in the Assembly Help tab.
I know some of you have been waiting, but I had to redesign and reprint this a few times before to finally get it the way I like it. My initial design and prints didn't have enough DOF, and my second design was too large to stay in a human size range. I tried to use parts of the bicep, but came to realize there was to much pressure/torque on the worm gear, so that also had to be redesigned.
|This was the initial design of the shoulders
|Then I redesigned the whole thing to get more DOF
|Final result of the torso with shoulders
Of course it could be much more improved but I don't have enough time and money for to do that. For exemple, the printed screw threads could be replaced with linear actuators, making it more accurate and strong. But I try to manage my wallet for this project, and I know a lot of you are in the same kind of position. So if you've got a thick wallet, you can replace those parts fairly easily. I have made the space for it and added attachment holes for to be adaptive. The others with a smaller budget can print and play, if it breaks, well, reprint. Or get them printed by Shapeways in stainless steel for a reasonable price.
|These are some of the broken and rejected prints I didn't throw away.
But be reassured, I've had these parts on for several weeks now and I have been making them run already quite a few hours, sometimes mistreating them badly, and they are holding. The main breakage I had, were during the implementation of the servos speeds and positions feedback, plus a problem with my power supply, which would make my servos act erratical. If they go further then the limits, they break.
Anyway, like I say following the tutorial should make it easy to construct.
I also need to upload the torso because the tuto concerns it too. My problem is that I'm not finished with it.
You see I need to think of the vertebra attachments to the torso and that might change a bit still.
We will see...