A screw in a printed part is held by plastic, and plastic threads strip when they are overtightened and wear when they are reassembled. The ways to give a printed part a thread are compared here: a thread tapped into a printed hole, a thread formed by the screw in crush ribs, a heat-set brass insert, a nut embedded from the side or the back, a nut trapped by pausing the print, and a printed thread for large diameters [1]. Each has a pull-out strength, a torque at which it strips, and a number of reassemblies it survives, and those three numbers decide the choice. The rules on the joint follow from the stiffness: the printed part is far softer than the screw, so the preload comes from squeezing the plastic, it is limited by the plastic’s strength and it relaxes, and dynamically loaded screws need a locking measure; a long screw keeps the part in compression and makes overtightening less likely. The joint diagram, the joint constant and the embedment in plastic are worked in the bolts chapter’s section on screws in printed parts; this chapter holds the rules and the measured strengths. Our test is the pull-out and strip-torque series that the strategy names first, replicating CNC Kitchen’s comparison of inserts, tapped threads and embedded nuts with a cohort’s sample size.