HC RR-spike knives make better letter openers and pry-bars than knives, but only in contrast to higher carbon steel and more sophisticated alloys. about like the mild ones but wil a little copper in them. Guru the Cu RR-Spikes then? not common but out there. If you want to avoid all this then you need to puchase new steel of a know composition, then heat treat it at the recomended temperatures. Testing unknown steels is a trial and error, as well as educational process. On alloy steels the colors are similar but not the same temperatures. Each color indicates a specific temperature on plain carbon steel. Temper temperatures are often judges by the rainbow of colors that appear on clean steel. Many "hard" tools such as hammers can be filed and others such as knives a file will scratch but not cut well. ![]() You want to temper to as high a temperature as possible and keep the necesary hardness. The minimum tempering temperature is 350☏ and 450☏ is recommended for many steels. Temper your hard sample at different temperatures until you find the right hardness. This also reduces the hardness but that is a necessary fact of life. Tempering is the reheating of the steel to some temperature below the hardening point to reduce the brittleness. 4140 is an alloy steel with 40 points carbon and 1095 is a plain high carbon steel with 95 points.Īfter hardening any common steel you need to "temper" it. Mild steel known as SAE 1020 has 0.20% carbon or 20 points. Points is a common term for the decimal percentage of carbon in steel. You always want to use the least severe quench that produces the necessary results. Water is too sever (too sudden) for these steels. Note that many tool steels are air hardening (no quench) and other are oil quench. If it hardens then it is probably less than 50 point steel. If it doesn't harden then try a little hotter (a low orange). If it slides off without digging in you have a hardenable piece of steel. Heat it to a medium red or a little higher than non-magnetic (steel stops being magnetic at 1435☏. Be sure to use firm pressure as lightly grinding can make small sparks that appear to be higher carbon than they are. Test a couple known pieces of metal and see the difference. As the carbon increases the sparks start to branch and get fuzzier and fuzzier. Wrought iron and very low carbon steel make long sparks with few branches. On a grinder in low light grind the sample and watch the sparks. As with all scrap steel the best thing to do is take a sample and test it.įirst try the "spark test". However, spikes were manufactured by many manufacturers and they vary quite a bit. The high carbon are 40 to 60 point carbon steel and supposedly marked "HC" on the head. RR-Spikes, There are two types a low carbon and a high carbon. Obviously they were too high of carbon for that treatment! Terrible things! I broke them no too long ago trying to straighten them cold. My first pair of tongs were made from spikes. But if you make a long slender blade it can be either too brittle or too soft. So if you make a relatively heavy blade like most hunting knives it will do OK. This results in a blade that is more brittle and prone to breaking. In a lower carbon steel blade you must temper less to keep the hardness. The result is a strong flexible blade with a hard enough edge to stay sharp. ![]() Most good blades are made of relatively high carbon steel (60 to 90 point) and are tempered way back after hardening. This is too soft for a great knife but good enough for an OK knife. I'm not sure what the carbon content is of each type, however many spikes have about 40 point carbon making them equivalent to a 1040 steel. The high carbon ones are supposed to be marked with an "HC" on the head. ![]() RR-SPIKES: There are two types of spikes, low carbon and high carbon. McMaster-Carr carries them in two sizes for 0.60 USD (look under spike). Sometimes you find them at fleamarkets and such. The rail roads don't like it, it IS ILLEGAL (tresspassing, theft). RR-SPIKES: Henry, Most folks pick them up along rail road beds. I've seen the "S" code also, but I don't remember what it stands for.Īs for finding them, I just take a walk along some railroad tracks and pick up cast offs.Ī good time is after they do track maintenance. If there is an additional "C" on the head, it means copper has been added to the alloy. I have been told that NON-HC spikes haven't been made since the 70's.Īll current spikes are HC, but there are variations. Non-HC spikes were about 20 points of carbon. They make better letter openers than knives. RR spikes: HC RR spikes are 30 to 40 points of carbon. There's more (other RR steels) if you're interested. on RR spikes, I found the following somewhere online: RR-Spikes : Spike Material and Use To a new blacksmith with hammer and forge every RR-spike looks like raw material! :)
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