Articulating joints for a mannequin made from 1.25" schedule 40 PVC pipe. The single knuckle 180 is for the shoulders, hips, ankle, and wrist joints. The single knuckle 90 inner-stop is for elbows and knees. Both utilize the outer knuckle and peg pieces.
The joints press fit into the I.D. of the PVC and permit a full 360 rotation on that axis, Some sanding may be required depending on the print finish. The same is true with the Peg.
The hole in the bottom portion of the pictures is from a previous test version that was not necessary.
Be sure the wall thickness is at least 1.2mm and infill is 30% or greater. When moving limbs , grip near the joint or else the joint may break.
Light sanding on the peg and O.D. of the base of the parts will adjust the amount of resistance for the joints.