The thing about half reamers is you can make them with simple equipment. I made my first one using a lathe, propane torch, a magnet, my wife's oven( she wasn't at home), a bench grinder, micrometer, and stones. Later, I made a TP grinder, which helped a lot. I'm sure a propane torch wouldn't be hot enough to make a 16 ga reamer. Ruined carbide tools can be very helpful in making other tools, such as boring bars, half reamers (shanks are already useable diameters), etc. Diamond wheels are great if you have them, but absent them, a "green wheel" will work. Since my shop was in the basement, I used water hardening steel to not generate oil quenching smells in the house. A happy wife means a happy life(57 years going on 58). It helps if you have a friend that owns a scrap yard in an area with several machine shops that bring "drops" and old cutters/tooling in, the drops are often the ends that still have the identifying color code intact.
Mike
