EricJergensen

Cary, The zinc will burn off the hot end of your burner. That's not really desirable, because airborne zinc oxide causes zinc fume fever. Airborne zinc oxide generally doesn't form until the zinc melts (787 °F). Even then it doesn't form much until it boils (1665 °F).

I prefer the term "face": Use the flat face. Use the round face. Tilt your hammer to use the edge of the flat face. etc. Still. Once you get Brian's terminology, you find his explanation pretty helpful. Does tend to start conversations / fights about terminology tho...

You'd either get an eruption of N2 in your face or a vapor blanket that kept the quenching from happening or both. Actually, look at the numbers: heat of vaporization of water is 2257 kJ/kg/deg C, for nitrogen it's a piddly 199! You probably couldn't get appreciable hardening with nitrogen at all and next to to thermal stress. That dewar of liquid nitrogen is already at boiling, whereas your water will absorb heat then vaporize and has more than double the specific heat. Even if it were colder than boiling, its thermal conductivity is in the range considered insulator. In other words, it's not about temperature (of the quenchant). It's about heat. Water will take away heat much more effectively than nitrogen.

Yes, SJS. The cost of new anvils sets the practical price ceiling. I'd by one of the (relatively) affordable ductile cast iron anvils from a reputable manufacturer like TFS rather than take a risk on a nearly as expensive used anvil from some random ebay or craigslist seller.

That's a good point. A ball bearing rebound test doesn't do much to tell you about depth of hardness. I suspect that a fairly deep 52Rc is better than a very shallow 60Rc for vigorous hammering. You'd need to drop something much heavier to approximate that. Like a 5# sledge head ... YIKES!

​I tried those and found that I don't like the stretch and snag. The stretch makes gripping harder. The snag is annoying when trying to hold any rusty or otherwise rough metal.

Gerald got an award (best of show?) at the recent Saltfork Craftsmen annual conference with this beautiful work.

Here it is running full. Cell phone camera doesn't cope well...

I'll get some pics at heat next time we light it up. It's working really well for the purpose: mostly 3/16" to 1/4" round stock. Josh: It was specifically made to do small stuff while going really easy on the propane. Main forge is coal forge with a Diamondback 1-burner economy for taking on the road. You're probably right, tho. One project leads to another...

Well, not sure if it's a soup can or not. 6" diameter, 7" long. 2 layers of 1" Inswool. Kast-o-lite 2600 on top of the wool. Burner is 1/2" pipe nipple w/ .023 mig tip. I'm pretty sure it runs slightly rich. Burner is intentionally off center to encourage swirl. Pictures tell the story...

Gave this to my family as an early present along with a ring mandrel my brother gave us. 17yo daughter spent the rest of the day forging rings from 3/16" stock. (Build details in Forges->Gas Forges)

First tongs. History: I bought a pair wolf's jaw tongs as my "bootstrapping" tongs. When I started to make chisels and punches out of 3/4" sucker rod, I needed something that would hold them. The tongs did work (and still do).

@LastRonin: no, my point is that table cutouts are not in line with the "cutouts" in the firepot (by what appears to be an inch). If you lay the end of say, 2' stock in the fire and the other end on the table cutout it will slant down into the fire. If you lay 4' stock all the way across, it will be more than an inch over the end of the 2' stock. It may not be a big deal. On my forge, that was more like 2" and was seriously annoying trying to get long stock to heat. It took forever to get it hot enough to bend down into the sweet spot of the fire. That said, his table cutouts are actually lower than the ones Centaur Forge makes. <shrug>. Why make lowered sides on the firepot and then bury them below table height?! Oh well.

I think your firepot is too low. If you lay long metal stock all the way across the firepot, you will be an inch(?) above the design height for the firepot. Assuming Centaur's design is right, the lower sides on the pot are level with the sweet spot and are there to allow level stock to be at the right height. That said, many people only work the ends of pieces and tend to slant them down into the firepot thereby reaching the sweet spot. I consider this a bad habit and try to always work with my stock level.

KRS: yes, that's exactly what I do. Stop the air and wait a few moments for the iron to cool back down to a non-burning temperature. As you point out, the reason it sparks only a little in the fire is the low O2 level. Pull it out and it sparks like mad, indicating that it's burning much worse.

Heat treating oven (finished, actually, but I'm still tinkering with the controller) 20 ton hydraulic press (should have all the parts this week) coffee can propane forge, 'cause my kids like to do little stuff like rings

That's quite a chicken and egg problem ;-). I can only anneal small pieces. I can only cut annealed pieces. So, in your experience, does it air harden or can you soften it enough by bringing it to heat and then air cooling?

The great smiths of yester-year made work that looked like it wasn't hand made. That was perfection. Being able to make 10 or 100 of the same thing with fairly high precision was impressive. Lack of hammer marks, etc, was attention to detail. Post-industrial smiths now often feature deliberate "imperfections" to emphasise the hand-made aspect of the work or for other artistic reasons. It's a different world now that machines turn out millions of items identical to .01" or less. So, depends on your goals...

Yes. 5160 and 1095 are both often used for springs. Your best bet for making strips quickly would be shearing of annealed stock. You probably don't have a shear, tho. (Shears come is all sizes, from ones that can only shear a thin guage to ones that can handle stock 1" thick or more.) Your other challenge is heat treating. To get an effective spring, you will need to harden and temper. Annealed stock has a fairly low yield point (the point at which the bent metal "gives" and won't spring all the way back). There are lots of resources on that here at IFI. Look in the heat treating section.

This is actually a rowing machine with pneumatic resistance. The weld failed. I'm concerned that it wouldn't be safe for me / the cylinder to weld it. In any case, I only have a stick welder not a spot welder. Repair suggestions?

oscer, Looking for stove pipe can cause health problems due to wallet shock. You don't actually need as heavy a product as that generally brings up. Metal duct is okay. Culvert is pretty good. If you can't find scrap, get seamed pipe -- even my local Ace Hardware has it relatively cheaply. 2 pieces of 6" seamed pipe can be seamed together to make a 12" pipe. Or, if you mail-order or look harder, you can find 12" seamed pipe as well. I spent a ton of money on my first setup because of the "stove pipe" thing. Later I found out that a forge draws significant amounts of cool air and the flue gas is not as hot as the exhaust an enclosed wood stove produces. Further, I was pretty scared of galvinized. Now I know that the temperatures that make zinc dangerous are much higher. (And, I'd bet money that the stuff I got had a zinc primer under the black paint.) Note: anything that touches your structure should be double-walled.

Right, hot roll always has "mill scale" on it. It's left to save money, but it also protects (slightly) the steel from rusting. So, as ken says, it has some scale to begin with that cold rolled doesn't. But the steel isn't inherently more prone to scale.

Inseam measurment for pants is also a good starting point. For most folk, that's fairly close to Thomas's wrist height suggestion.

I use regular 20 mule team borax (laundry booster) for my flux. In that form it is hydrous (is chemically bonded with water). Putting it on hot metal (orange heat) quickly drives out the water and melts the now anhydrous borax (melting point: 1,369°F). With that flux, I can't use Frosty's low-temp approach. So, I clean the piece (sometimes by grinding), heat it to orange, give it a quick clean-off on the welding surface (don't waste time with any other surfaces) with my butcher block brush, get flux on it quickly and then get it back in the low O2 environment of the fire. If you have a commercial flux, it will probably be borax based with other ingredients like boric acid (melting point: 339.6°F, boiling point: 572°F). Not sure what else might be used for lower melting point or coverage between 572°F and 1,369°F.

Do not build up the face to make it flat. Do not machine the surface to make it flat. Flat is not important. Hardness of the top plate is. The top plate is *not* wrought iron. It is high-carbon steel that has been heat treated. Any welding on that will ruin the heat treatment near the weld. As Fatfudd says, do your research. You will find that unless the anvil is in truly horrible shape, you're better off using it as-is.