Ethan Paul Dobbins

Here is a temper chart, and a incandescent chart, that i downloaded off of google a long time ago.They are not poster sized but you could print them off at a library that has a printer if you don't have one.

Oil for hardening steel, you might as well just get a jug or two of plain vegetable oil from the store. It will work as well as anything else besides Real engineered quench oils that work better, but cost a lot for a beginner. For hardening water hardening steel, Large pieces like hammers and whatnot, or just cooling off mild steel,A bucket of water will do fine. if you're doing a nail just put the hot nail in the header over the pritchel hole and hammer the head onto the nail. It will cool off on its own.

The grain does look a bit large, especially in the third picture. If you do your first normalization at a higher temp say just under 1600 degrees just to make sure you get everything into solution and without really trying to reduce the grain size as much as trying to get it all equal size with this heat, then drop the temperature of the next one to 1500 then drop to 1400 and do a couple at as low of a temperature as the magnet will not stick to you might get finer grain structures that are more equal in size. Make sure you ramp up your heat slowly so you do not overheat the tip or edge. I like to do it in the shade to make sure The colors are not too hot. I attached a picture of a color/temp chart showing the number of cycles I do at each heat. sometimes i will do extra, just depending on if I feel like doing more than usual, and intuition. I tried to take a picture of the grain size i get doing this, but an ipod camera seems to not want to focus very well. I will tell you it is comparable to a broken nicholson file, though somtimes slightly larger but I am very happy with the results .

The rod you sparked looked like high carbon, but the first block looked relatively low in carbon. brake rotors like that are usually cast iron, and it could make a good fire pot for smaller work. The round block looked to be a little higher in carbon than the first block, but i don't usually do spark tests with a dremel. The speed and type of grinding wheel you use can change your spark test a little, But I would say you could get some hardness out of the blocks if you heated them to non magnetic and sprayed them down with a hose, and maybe dump a bucket or two of water on them. You'll need a lot of coal or gas to get them that hot though, so you might be ahead to just use the bigger one as an anvil as is. hot metal is a Lot softer than even cold mild steel, so you should be able to forge on that larger block for a while.

It's not worth your time to try to fix a crack, because short of cutting it off and forge welding on a new tang, or cutting it up, stacking it, and forge welding it together into a billet, there isn't a way to fix it that isn't prone to failure. It will be easier and quicker to just throw it in the box of broken projects that everyone has in the corner of the shop, and forge a new one and make sure not to hammer below a red heat so that it does not harden and crack again Or, if you were using scrap steel like leaf springs, it might have had a pre existing crack. Also it is my opinion that If you have one crack, there is probably another hiding somewhere in the steel that you can't see yet.