Ken Nelson

I would second Ric's suggestion of getting proper salts, as they are meant for heat treating, and you can get test materials and other supplies for keeping a neutral environment at the same time. You might be able to work out a purchase at a local heat treat facility. I purchased my high temp salts from a heat treater in Milwaukee rather than try to get them straight from Parks. I also was able to buy 5 gal of Parks 50 from them at the same time. If you can find someone there to help, have them show you their set-up, and how they maintain their salts and safety, while you will probably need to scale it down, a day watching, talking, and learning from them may be worth more than a month's worth of Googling. A quick way to help make sure your blades have no moisture on them when going into the salt pot, is to have a oven set to 300+, and bake the blades for at least 15 minutes to make sure the water has evaporated. Or hold them next to the salt pot in the heating chamber to do the same. Best of luck, I know I love my salt pots. Oh, and make sure that the welds on your pot are top quality, you don't want a crack starting there and have 1500 deg molten salt running into your heating chamber.

There are a few key points to remember when dealing with springs, prods and blades. First, flex vs bend. When a piece of steel flexes, it moves from it's original shape a distance and then returns to true. In the flex range there is no damage to the steel, at least not until you start reaching 100's of thousands of cycles. Car springs and axels flex constantly and hold up quite well, but may eventually fatigue. Bending is what happens when you exceed this motion. the steel deforms permanently(takes a set) and is damaged. That piece will never be as strong again. you can thermal cycle it to relieve the stress and re-heat treat the steel, but it has also changed by thinning or stretching a bit. Second, the range of flex of a given piece of steel is determined more by geometry than heat treat. if you were to look at two pieces of steel, both the same alloy, length, and hardness, the thinner one wil flex further than the thicker one, while the thicker one will be more difficult to flex. Think of a 10" bowie vs a 10" fillet knife, or if you would like a more extreme example, 10" by 1" by 1/4" thick 1095 hardened and tempered to a RC 60 may flex only 40 deg or so before bending slightly and then breaking, while a 1095 shim at 10"x1"x.002" and same hardness may be rolled up on itself 3 or 4 times and still return to true. Heat treat makes more of a difference once the flex limit has been reached. A fully hardened piece say RC 65+ will snap and shatter if the flex is exceeded, while an anealed piece of the same alloy will bend quite a way before finally tearing. Cracks, micro cracks, and even deep scratches can play XXXX with flexing and bending steels though. the bottom of a scratch, or crack will act as a focal point for stresses, and can cause steel to weaken dramatically, or fail at ranges and pressures much lower than expected, often with dramatic results.

Steve, you are right, I did meant to write tempering, but I should know better than to post when I am tired.

That is a good method for differential hardening, and will probably serve well enough with any of the many steels used for leaf springs. Please remember though, flex is dependent on the geometry, not the heat treat. a softer blade may bend when flex is exceeded, a hard one may break, but at a much higher force.

Brownells has Toughquench, and MSC has a quench oil that is similar. both are quite similar to Parks AAA, which I believe is still carried by elliscustomknifeworks.

while an oven can work well for many simpler steels, H13 should not be tempered in an oven.Crucible steel recommends that the steel is tempered at 1000-1200 deg F. Fully hardened h13 drops only slightly in the range from 400-800 deg, and then gains a point or two of hardness again at 900 deg F. the higher temperatures are recommended to get the H13 out of the brittle tempering range.

Steve, I also like using L6, as it has some of the best qualities for a sword. If I do not want to spend as much time on annealing (as you have to fully anneal L6 or it will chew up your belts and bits) I will turn to 8670, or BE 5634 (a European grade 75n8) Both of which I get from Bestar. The steels listed above are all intended for use in industrial saw blades. All of them have Nickel in the mix from about 1-2.5% All have been designed to take abuse while still being able to cut tough fibrous materials, and hard materials. If all you have is basic heat control, you may want to stick with 5160. If, however, you have the equipment to properly control your annealing, and hardening temperatures and times, you can get more performance out of saw blade steels than spring steels. For example, I sent some pieces of 8670 and 5160 for impact testing, and found that the 8670 could have the same toughness as the 5160 and still be 2-4 points RC higher. In other words, the 8670 could be just as tough and hold an edge a little bit longer. Mind you, on the other end of things, I have also used 1075 and my own shear steel for swords in the past. Both of which have performed well.

what type of use? stage, fencing, or combat? it may make a difference, and adding to that, you probably do not have the heat treating equipment to produce rapiers that would pass for inclusion into fencing associations, those standards can be very strict and often require high levels of control. All in all though, I do not find 5160 to be the best steel for any sword. there are other steels that have better combinations of toughness and edge holding. look through the steels used for industrial saw blades, you will find steels that are more suited to a sword than steels that were designed for springs.

I am not sure about your choice of steels, 1095 tends to be a little too brittle for swords. I would recommend using 1060 or 1075 instead. Yes, it is possible to temper back the blade further, but using a lower carbon steel to start with will give you a better martensite structure for a sword.

Greetings, You mentioned there was some more information on the wrapper, could you give us all of that information? It may help to determine exactly what steel you have, and what would be the best temperature and time ranges to work with.

There may be a different problem that is being overlooked here. 1/32" is quite thin, and has little lateral strength. Hardening and tempering to a higher hardness may help, but if you are not driving the punch directly forward, then you will get flexing and bending in the punch. One thing to check would be the punch holder, how straight does it hold the punch, is there a angle near the top of the barrel, and is the hammering surface directly in line with the punch? Any of these could impart lateral forces. If your son is not coming down directly with the hammer blows, you can get the same problem. The ends of the punch are important too. In a case like this they need to be exactly perpendicular to the shaft, or the punch will flex/bend opposite the higher edge. One other thing that may help would be to make the punch as short as possible to get the job done. While heat treat is important, and getting a good even hardness will help tremendously, I think there may be more than one dimension to the problem. Good luck

When sharpening by hand I use diamond stones, if a blade is badly worn or damaged, I use a flat chainsaw file to do the rough work, often draw filing to set up the edge.

Robert, thanks for the link, that was very interesting. I had not seen a good experiment with vegetable oils before. I had recommended the mineral oil, as it is easy to get, and is consistent from year to year and batch to batch, and is more resistant to oxidizing. However, I don't think you could pay me to go back. I am much more happy using quenchants that I know match the steels I use.

Parks #50. It is a fast oil that works very well for simple carbon steels. It will even work well on W1 and W2. veggie oil may work, but you will likely have some fine pearlite left in your blade. If I was to use an oil that was not made for heat treating, I would go with a straight mineral oil, the type you find in farm stores for treating cows.

back to the cable question, I am not sure it would be a good cable to start with. IIRC 6x37 means 6 cables of 37 strands each wound together for the total. That could cause two problems. First, a good cable for welding would be 7x7 or 7x13 which means 7 cables, including the one in the center. The 6x37 probably has a synthetic center that will cause all sorts of problems with welding, or allow the cable to collapse, giving it only as much mass as a 3/4" or 7/8" cable. The second problem would be the size of the individual strands. When you weld a cable together, you will get a decarb layer on each strand. In a way this is nice as it adds to the pattern, but on thin wires, you can lose over half of the carbon in the steel while you are welding. a single wire in a 7x7 is about .111" dia. If you were to only lose carbon in .005" all around, you would still have .101" of good steel in each strand, or about 82% of the wire. in 6x37 each wire is about .045" by the time you lose the decarb, you have a .035" center, or only about 60% good steel. The cables I have used in the past are 7x7 aircraft cable bright finish. Those are available in various sizes, and are not coated or filled with any plastics or fibers.