I needed to turn some custom parts with a hose barb on one end. This wouldn’t be very hard on a CNC lathe, but I only had a manual lathe. To make a custom shape like this, a form tool is used. This isn’t a technique I invented, obviously. To get my part shape, I had a custom form tool cut by a wire EDM machine at another shop.
To use the tool, I roughed the form close and then plunged the tool in to finish the barb form. It made quite a lot of noise, which might have meant the tool was over center a bit. It was a little hard to set the height. I got the parts done, none the less.