This is for grabbing an output jack that is installed in a guitar, mostly to tighten the external nut while preventing the jack from turning.   All you should need is the long piece to go inside the “key” and the key.   Install long piece so that the taper at the end will flare the key when pulled.  Insert the key into the output jack.   Pull firmly on the long piece, to flare the end of the key, and then pull on the key to lock it in the jack.    I tried this and it seemed to work.   I have also included a threaded flared piece if you wish to use a #5-40 bolt, and a threaded knob.   However, you might have to tap both pieces as the printer might have trouble printing fine threads.   I tried making a plastic threaded piece, but it was thin and broke too easily.   You don’t need the small flare or the knob if you are just going to use the push/pull.