Hing Joint

The joint that I decided to make first was the elbow and knee joints. I used a spanner style hing joint. This type of joint allows for a full 180 degree bend to give me as much articulation as possible.

 

The start of the sketch was just a basic rectangle with a divider on where I wanted the upper arm and lower arm to fall.

Next I extruded the upper arm and made some sketches to make the space for the spanner in the center and the circle on the side to trim the arm to make space to allow it to bend.

 

 

Then I extruded the sketches and added a chamfer.

 

 

 

I then did the same for the lower arm.

 

 

 

Then I used the following sketch to create the cones for both the arms and the spanner.
The clearance was set at .5mm, the first test I did of this joint was at .02mm because I was told that was what to set it at. Turns out it was .02in, not mm, and that translates to .508mm but .5mm works as well. I also tried to print this on another color filament that didn’t work so I think I might try to tighten up the clearance and try again.

 

This is how the joint ended up as. I think I’m going to try the joint with some cylinders after Dr. Plante’s suggestion. The space would be small enough to bridge that gap and it’ll help the joint be a bit more consistent with other materials.

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