Knife out of an Auto Leaf Spring

[akapennypincher]

Anyone ever build a knife out of a Auto Leaf Spring? I did this back in High School, and the Leaf spring worked wonderful. i use to get them for FREE at the auto Wrecking Yard. The owner always accused me of making KNIVES, but i told him I was making Ab Irons for Harvesting Abalone via scuba. think he believe me... :rotf:

 

[PitchyPine]

Yep but it`s getting harder too find thin ones if any at all.

 

[rebel727]

Yep but it`s getting harder too find thin ones if any at all.

I had a bunch of them from the 50's that prolly would have been thin enough but I recently sold them all for scrap. I've got a short pry bar that was made from a cut and quartered model A spring. It would make a dandy knife. My first wifes dad made hunting knives out of old Civil War sabers back in the thirties but I guess that would be cost prohibitive now.
:rotf:

 

[ameling]

I've known a few friends who have made knives from vehicle leaf springs. You can make a good knife from one. But they are getting harder to find. Most vehicles have gone to using coil springs or torsion bars. Different manufacuterers used different steel alloys over the years, but most tended to be 1085 or 5160 steels. Vehicle coil springs tend to be 4063 or 5160.

But you might want to look to your lawn mower for steel. The blades tend to be 1085 or 5160 - just like those old leaf springs. They also come in several thicknesses - 1/8, 3/16, and even 1/4 inch thick. And somewhere between 2 and 3 inches wide. But most importantly, you can generally get all you want for free.

One little note about car leaf springs. A friend made his throwing knife from a '54 Ford leafe spring many years ago. He cut it to length, forged it to shape, and heat-treated it properly. But it always reverted back to that slight curve from the original leaf spring. A couple of throws, and it had that slight warp to one side. Old re-used steel can have some "memory" from its past. It's a known hazzard. That's why most professional knife makers always start with new steel - no "past history" to cause problems, especially at the end after spending all that time working on it (cracks, warps, uneven heat-treat, etc.).

Just some humble thoughts to share. Take them as such.

Mikey - that grumpy ol' German blacksmith out in the Hinterlands

 

[Charles D. Prokopp]

I use leaf springs for all of my knives. The steel is easy to forge, heat treats easily and makes a great blade. To overcome the "memory" issue, I normalise my blanks by heating to red hot, then cooling slowly in the forge to room temp. Repeat the process three times. Makes the steel easier to forge and a lot less prone to warpage.

 

[paulvallandigham]

I made my first Bowie Knife from a truck leaf spring that dated to before WWII. it was about 3/16" thick, and you just can't find leaf springs that thin now. Most today are 3/8" thick! We annealed it by heating it to almost white hot in a stack of wood we burned, and let the steel cool slowly in the ashes for 3 days. I proceeded to cut and grind and file away anything that did not look like a Bowie Knife, and quit when it was done. There has to be a better way to make a knife, and there is! :surrender: :hatsoff:

 

[Charles D. Prokopp]

Yeah, Paul, you sure did that the hard way!

 

[boar]

n my country some of the knife makers are using Amish buggy springs. I made one throwing knife out of a car spring. The way we got rid of curve was to get red hot and wipe back with rag of cold water. Steel has a memory, it will go back flat. Have two throwing knives made out of mower blades. Rotto tiller tines are good for flint strikers and knives.Dilly

 

[bocalbender1]

The cold water trick is some times used to get stubborn dents from old auto bodies. I think I'll give that a shot for my next knife! Thanks for that tip! :thumbsup: BB

 

[Johnny Tremain]

Dang,

I just sent a few model "A" springs to the scrap man.

They would have worked real nice.

We have old car swapmeets here 2x a year. You can go there and pick up springs for 5-10 bucks.

Also on-line car forums the HAMB

 

[wildeagle]

Good tip johnny :thumbsup:

 

[vikingsword]

Leaf spring that are used for small trailers are just about the perfect size to start with on most knives. Any spring steel material you salvage is going to be tempered and in pretty much a non-straight form, if you have the capabilities to heat it up to or above 1550 degrees you can straighten it out and not ever have to worry about any memory it had. This can be done with an oxy/accetalene torch, if the piece is not too long, a rosebud tip works well. If you do have access to a forge and are going to forge it out to shape then it will not be a problem anyway. Sometimes a welder in your area may have one, if not check for a farrier, or even a clay potter who may have a kiln to at least bring it up past this temp as it will also soften this steel so you can work it with grinders or files. At one time all my custom knives were forged from salvaged spring steel, or old files, or old hay rake teeth,or old tractor seat springs, or, well you get the picture, the posibilites are endless , old files can be some of the best. vikingsword

 

[Blizzard of '93]

Volkswagen springs from the rear suspension up to year '69 makes excellent heavy blades. a soak at bright red will lay 'em flat.

 

[ameling]

There are times when "old steel" just hangs on to its past "memory". My friend did anneal that '54 Ford leaf spring. He also forged it to shape in a traditional coal-fired forge. And he did a very good job of heat-treating and tempering the blade. But it still "warped" back to that original curve of the leaf spring in use. He also repeated that whole heat-treating process several more times, including once with a professional knife maker. It still retained that past memory. Logic and technical experience/knowledge said it shouldn't, but it did. So sometimes that past can come back to haunt you.

This did happen with one friend who is a professional knife maker. He spent most of 40 hours forging and hand-finishing a knife blade from "old steel". But in the final heat-treat, it cracked! Yes, he really did know what he was doing and had already reached that Master Bladesmith level. That "old steel" just had internal problems that did not show up until that final heat-treat. So he had to pitch it. That 40 hour "lesson" was not lost on him. He now starts with new steel.

He also learned that lesson to NEVER just pitch a bad blade into the scrap pile. Somebody will come along, fish it out, slap some handle on it, sell it to somebody else, and then have that "knife he made with his stamp/mark" come back to haunt him - for shoddy workmanship! He also doesn't sell any blades to anybody else for them to finish - because you never know how good of a job that other person will do putting a handle on it! And with his stamp/mark on that blade, the rest of the work on it also gets linked back to him! Another hard-earned lesson.

Every time you re-use "old steel" from whatever source, you run the risk of having problems with it from its past. Doing this for yourself only affects you. But doing this as part of your business has far ranging consequences. How many people can afford to ... waste ... a whole weeks worth of labor in their business?

I sometimes use old steel for a number of projects. But it does occasionally come back to haunt me. But most of my projects are small, so the occasional loss has not stopped me from using/re-using old steel.

Just some humble thoughts to share. Take them as such.

Mikey - that grumpy ol' German blacksmith out in the Hinterlands

 

[vikingsword]

I would like to have seen this particular project knife that failed, I've never run into that problem in my 19 years as a knifemaker but I never stop learning and there's always something a person has never seen before. I have no doubt that your proffesional knifemaker friend knew exactly what he was doing,All of the best of the best run into problems with a knife or two on occasion. I've found that if a piece of steel has a set that give me repeated trouble that I must bring that piece up over 1800 degree's for a time, which I do in forging anyway, that way the molecular memory is rearranged to your forgings, making It very important to forge evenly on both sides of the blade lest you creat uneven stresses when the blade is forged down below critical temps. If you do not, warpage is almost immenant when the blade is heat treated. Files can present their own set of problems if the teeth of the file are not ground away first before forging because if they are forged in to the blade, they can cause undo stress points along the edge and create micro cracks upon hardenig the edge, not always but it does happen often. I use mostly factory barstock these days,as it's very much easier to use since salvaged steel usually dosen't come in a very usable proportion, and doing this for a living means time is money,( I hate that aspect of the business), and it can be a real pain if every time you want to forge a knife you have to reproportion a piece of steel before you actually start forging the knife. The only exceptions I make these day's is for my ball bearing blades, as that type of steel(52100) is not readily available from a factory, and when it is offered the price is too much. Wes

 

[Blizzard of '93]

Viking do you use the balls or the tracks for the blades? I know it is very tough hard metal.

 

[vikingsword]

I use both ball and roller bearings, and their races if they are suitable. Not all bearings are usable however because some makers will use 440c for bearings, which is stainless and air hardens during forging( It can be done but all at very high temps, and requires a complicated heat treat i'm not set up for). Some other bearings are made from very high quality mild or low carbon and are simple case hardened. I always test the first bearing from each batch for hardening capabilities so I don't waist my time forging out an entire knife and have it not harden( first time doing that,was the last). I have a pair of little giant powerhammers that draw a bearing up to two inches around down to a usable billet in just a couple heats, then I hand forge them using a hand hammer.Wes

 

[LFC]

Just as a matter of interest, here's an outfit whose smiths make their stuff (usually) out of old truck leaf springs.
[url] http://www.himalayan-imports.com/khuk1.html[/url]

 

[rich pierce]

another source is farm steel especially harrow blades.

 

[Desert Rat]

With all the talk about lawn mower blades and other options. Can a knife be made out of a mower blade without forging? I haven't paid close attentention to mower blades to know if it could be ground down slowly.