Assumes basic knowledge about creating and modifying objects in Fusion 360.
These steps will show you how to create a 10mm Ball and Socket Joint that can be scaled up for larger applications.
Step 1: Step 1a: 10mm Ball Shaft
Use Create > Sphere to create a 10mm diameter sphere at the 0,0 origin point.
Step 2: Step 1b:
Now use Create > Cylinder using the same plane as used for the sphere and the 0,0 origin point as the start. Give it a 5mm diameter, extend the cylinder to 15mmn and change the Operation to Join.
Select the body and Right Mouse Click (RMC) for the menu, then use Create Components from Bodies to change it into a component.
In the object tree, RMC Component1:1 and select properties. Set the Part Name to BallShaft.
Finally, click the yellow light bulb for the BallShaft:1 object to hide it.
Note: When printing the Ball Shaft, have the shaft base on the plate and the ball above it.
Step 3: Step 2a: 10mm Ball Socket Shaft
Use Create > Sphere to create an 11mm diameter sphere at the 0,0 origin point.
The slightly larger 11mm sphere will give a bit of clearance for the 10mm sphere.
Step 4: Step2b:
Hide Body2 (the sphere you just created) and use the same steps to create a 13mm sphere at the 0,0 origin. This will be Body3.
Unhide Body2, which in now inside Body3. Use Modify > Combine to Cut Body 3 with Body2.
Step 5: Step2c:
Use Construct > Offset Plane to make a cutting plane. Unhide the Origin object if the XYZ planes do not show. Select the plane between the Blue and Red axis and extend it down -2.00mm. Select FRONT view on the positioning cube to get a better reference. You can also unhide Body3 to see where this plane will be relative to the sphere.
Step 6: Step2d:
Use Modify > Split Body to cut off the bottom of the sphere. Make sure that the Extend Splitting Tool box is checked.
Step 7: Step2e:
Hide Body3, Body4, and Plane1.
Use CREATE > Box to create a 30mm x 2mm x -20mm box.
Step 8: Step2f: Cutting the Releaf Slots.
Move Body5 (the box) 1mm along the Z axis, 4mm up along the Y axis, and 15mm along the X axis.
Unhide Body4. The box should now be in position to cut 2 slots in the upper half of the sphere.
Use MODIFY > COMBINE to cut the slots. Make sure that the Keep Tools box is checked.
Step 9: Step2g:
Hide Body4. Select TOP view from the view cube.
RMC Body5 and select Move. Click on the Set Pivot icon and move the pivot point to the origin 0,0. Then click Done for the Set Pivot. Now rotate the box 90 degrees about the origin.
Step 10: Step2h:
Unhide Body4 and cut two slots as before. This time, you do not have to save
Step 11: Step2i:
Hide Body4 and construct a 5mm diameter Cylinder 15mm long started at the
Step 12: Step2j: Attach Post to Socket
Unhide Body4. Move Body6 up 5.5 mm to the top of the socket.
Use MODIFY > Combine to join the socket with the cylinder. RMC Body4 and select Create Components from Bodies. Then select Component 2:1 properties and change Part Name to SocketShaft.
NOTE: This is the orientation for printing the Socket Shaft
Step 13: Summary:
Congratulations. You now have the base components of a Ball Socket Joint.
These can be scaled up, but 10mm seems about the limit for small. I've had limited success down to 5mm. At 25mm, it makes a nice robot arm socket. Just add some flanges to attach control wires to the shaft.
The picture shows a 20mm, the 10mm, and a 10mm with a flange added for building a tentacle.