With the bung cut, faced, and drilled (1 ½ x 3 inches cold roll steel) – I am now ready to tap for 5/8 – 18 threads, which are what I use for my urethane rod ends. The large item that is over the bung blank is a tap guide bushing that I made just for this purpose. Putting threads into a round piece of stock is almost impossible without one of these bushings or a lathe. I show how these are made in my DVD on chassis and frame construction.
There is an order to making these bungs and if I vary by much, then I might not be able to hold the bung in the chuck so that I can cut the taper on the end. Clamp the bung using the pipe jaws found on most vises. Slide the tap bushing over the bung, I insert the tap, lubricate and using the largest tap handle and a good pair of leather gloves, begin cutting the threads.
After the tap is started and the top of the treads are at the top of the bushing, I back out the tap and clean it off – remove the guide, reinstall the tap, and continue the tapping process until the threads are all the way through. Blow the threads out with compressed air (wear safety glasses) and do the same process to the other bung.
The picture on the right shows the bung with the threads cut and no taper. If I didn’t have a lathe or didn’t know how to cut a taper, then I could use the bung as is. The picture on the left shows a bung with the taper cut and ready for installation.