Warning: metal content.
Gotta trim a roller chain to length on site at the end of my dock, this for the motor drive for my boatlift. I design stuff up to a point, but don't get anal about it -- there comes a time to shoot the engineer and make something that works.
I found with Google search that cutting roller chain to length is customarily done with a "chainbreaker", saw some photos. So I made one tonight that I can use on site, got it RFN at no cost -- since the lathe, mill, TIG welder and rawstock were already at hand. (hee hee!) No drawings, just make the SOB. Turn the cranks, don' need no steenkin' CNC to make a one-off. I like turning cranks. Held a tolerance of +/- .0005 where it mattered, easy peasy with one setup and a reamer. The drillrod ram slides in the hole slick as loonshit with no wobble 'tall, not a bit of it. Making it was about as fussy as frying an egg.
Couldn't resist giving it a black oxide finish since it only took a minnit to do so.