Fixing Steam Air Vent Hole (Bushing Stuck and Rusted)

Steam heat likes to rust everything that isn't copper or brass. This results in old steel bushings (1/4" to 1/8") getting stuck, and if the threads are degraded you have a problem on your hands when you try to replace the air vent. This video shows how to remove the old bushing with a drill and tap. These NPT kits are easily available on Amazon and usually at your local plumbing store. They are very useful so are sometimes sold out.
You can also use this technique to enlarge the hole further and use something like a 3/8" to 1/8" bushing to get your system working again.
Remember to turn off your steam before working. This is for entertainment only and you should consult a pro if you are unsure.