Greenbuggy

Petere76 said "milwaukee end mills" but the correct term is "Annular cutters" made by Milwaukee, Haugen, Jancy and others. You could use those after drilling first with a regular drill bit to get a flat bottom, another thought is a custom ground cutter in a boring head (again after drilling the hole to desired depth with a regular bit)

Had a thought the other day as I was picking up more propane for my gas forge....what alloys, or types of steel are handheld blacksmiths hammers usually made from? Some quick searching didn't turn anything up.

Hi there I recently discovered this site and it looks to be a real wealth of information, and inspiration for some projects I'd like to make as well. I have recently constructed a freon keg forge, with space for 2 burners although for now I have only one installed. The forge is lined with Kaowool, soon to be covered with plistix, and the burner is very similar in nature to the ron reil EZ-burner. I recently picked up a copy of Porters "gas burners for forges, furnaces and kilns" and have been reading thru it. I see a lot of parallels between his forge burner designs and the mongo burners on Reil's site. Also some definite similarities to the hybrid burners with regards to the sliding chokes. Naturally I'm wondering about how to improve what I've already got built and to that end I did some cleanup and polishing on the inlet and outlet of the black pipe fittings in my ez-burner with some slight improvement in the temperature of the forge. I know that the refractory coating I'm planning on using will improve the heat retention inside the forge and make parts get to heat faster, but I've got something I've been wondering about burners as well. Most of the higher performance ejector burners I've seen like those in the Porter book and the hybrid burners, use a sliding choke over milled slots. I have to wonder if some improvement couldn't be gotten by milling a series of holes in the tube off-center, or using a rotating choke that is flanged in such a manner that it causes a spiraling column of air as it moves through the pipe, intermixing with the gas a bit better before entering the combustion phase. My inspiration comes from seeing burn barrels with triangle-shaped openings bent in on the bottom to cause the air to spiral around the burning trash to ensure a cleaner, hotter burn. I have an old bridgeport mill and some time to blow so I wouldn't be opposed to killing a few 3/4" black steel pipes to test my theory, but would like to know if anyone else has contemplated doing something like this, or seen something like this in action before I start making chips. My understanding of fluid dynamics is a little rusty, you know?