The parts are covered by a tin cap. Which I also need. There is a knurled knob, spring, and something else or two, but have not found a pic of one without the cap. Ideally if I had a piece to copy it would be good, or even a good picture, as I can get pretty inventive. Pictured is the top of my drill, and a nice complete one. The knob was turned or pushed to control the amount of down feed as one cranked.