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Leafspring steel


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I have been using leaf spring steel for my fist 3 knifes I have made and would like to know if what I am doing is correct?


forging to about 1/4 inch

Grinding and shaping

heating to orange heat 2 times letting it sit to cool both times

heating to a bright orange almost yellow heat and cooling in corn oil preheated

tempering in oven at 450 for 1 hour

sanding and finishing


this was my first proper knife done with the leaf spring

the handle is Heart wood from Africa that my wood working buddy gave me.. not the best pic



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Welcome to the site. I am not a fan of using colors to determine temperature for hardening blade steels. Ambient light is a key player in this problem.

However there are simple shop tests to see if wot you did was right. I take a file and see if the steel is hard right after I remove from the quench, Then with a hard test sample I have forged to a blade thickness and hardened I break it and look at grain structure, If you have overheated the steel in hardening steps it will have really large grains and that makes for a poor knife blade, And if the grain is right then I temper and see how the blade flexes and holds an edge,,,if all is well I make a knife, And don't forget to use a magnet if you like to find correct heat for hardening,,,,All of this and more are in the knife making lessons in the forum.

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"The proof of the pudding is in the eating"; so use tests  should indicate if it's hard enough/too soft/too hard, tough enough, etc.


When working on a heat treat for a steel new to you it is common practice to forge a bunch of simple blades and test to destruction for differeing heat treat processes.

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"Leafspring" steel can be just about anything.  If it is from a modern automobil or truck then it is most likely some version of 5160 in which your temper is too much for a knife that size (k, that's my opinion you'll just have to work it out for yourself).  Your probably floating around 54rhc while most makers would want it in the 58-60 range.  A temper at 400-425 should get you there.  Remember, you can always raise the temp if it's too hard but getting it hard again is a whole other story.  It's always good to know what you are working with unless you like to experiment and waste steel, time and fuel for the experience. :blink:   As for the finished knife, well done. B)

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Considering all the variables, I'd say you're doing the best you can with what you've got.  Not knowing the type of steel your working means that you have no chance to maximize the performance of the steel with the proper heat-treat regimen.  You knife's performance under use is the only way to judge it; just hope that the blade doesn't snap in two some day down the road.


I will say, though, that forging to about a quarter inch is leaving a lot of meat that still has to be removed by files and sanding.  On a knife the size in the photo, I wouldn't want a spine thicker than 3/16", and that's for a beat-around-the-woods kinda knife.  I would suggest that you spend more time with your hammer practicing good hammer blows so you can bring your stock thickness down to almost-finished and have a smooth surface.  Make sure your hammer faces are dressed well, and buy or build a flatter.  Otherwise, you're burning up resources to reduce the metal past all your mule tracks.

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I take the other side of the road on this: If you have and unknown steel you can do rather simple shop tests and see if it will indeed harden. Then with more testing with different tempering times and temps you can indeed get the most out of that steel if you are willing to spend the shop time to go through the steps needed. And of course wotever you find and record that works will only work on that particular piece of steel. In a stack of leaf springs it would be a good starting point but each leaf needs a confirmation.

All that said I prefer to buy new steel from a rather short list of wot I have data on and like how it works and performs. A call to a supplier and for a fair price it is at my house in a few days. I sell knives so I have to be sure that wot I put so much work in is up to my standards. And as a big part of that I am very careful of the suppliers I use. If in the unlikely event I would try a  new supplier, the first shipment would go through my shop with a close eye on how it matches with my expectations.

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