Grease Gun Knob for 5/16-18 thread

Lost/broken the knob off the end of your grease gun's ram-rod? if your grease gun uses the ubiquitous 5/16-18 thread, then here's a replacement! The thread fits nice and tight, just like a lock nut, so it won't unscrew accidentally. Print it in something tough if you want it to last, or just use PLA or ABS and plan on making another in the future...