Anyone know what this mechanism might be called? Need something like this or similar, but the tolerance and overhangs are not treating me well. Basically im building a knob. A threaded bolt slides down inside the knob until the bolt head fits in its relief. This keeps the bolt from turning, but doesnt keep the bolt from moving up and down. Pic related is built into the knob. Once the bolt is in place the little plugged end is supposed to push and snap into place on top of the bolt sealing it in the knob. Tried doing a threaded plug but its not printing well.