eseemann

Has anyone tried cold working a leaf spring?

36 posts in this topic

Good Morning, 

I was searching YouTube for information about re-arching leaf springs because I am thinking about ordering a champion power hammer spring once I find a shop in North Alabama that can do this work. I saw a video of Pakistani smith cold working a leaf spring and I wondered what you good folks thought about that. I figure hot working the spring and then re-tempering once you are done is much easier to say that do. 

thanks 

 

 

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I don't know that you'll get very far doing that.  It didn't look like he was.  Alloy content will contribute to the problem too.  So no, cold working tempered steel isn't a good idea. 

I don't know about the rest of the guys here, but if I caught someone doing that on one of my anvils they'd get knocked up side the head with a bucket of coal at minimum.  That is how one ruins an anvil.

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JM, 

Thanks for the information, it seemed like it might not work that well but I thought I would ask. 

 

Ernest

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Stress cracks, uneven work hardening, anvil damage -- where to begin? At least with a car spring, if it breaks, it's got a car on top of it to contain the flying pieces. If your power hammer spring breaks, we'll be reading about you in the Prayer Request section of IFI.

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Have a look for Forgemaster's posts on working spring steel. Phil's method is to heat to greasy stick temperature and then set to the required shape, the greasy stick temperature is the tempering temperature so you do not need to re heat treat after setting.

 Search on "greasy stick"

Alan

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That is one of the things I had in mind when I told my wife that I would want someone else to show me how to build the LG type linkage since it would be right next to my face. That is why I am either going to get a spring shop to make a "champion" style spring or go with a "Rusty" style spring. 

Alan, 

I will do just that. Have you ever used the temp sticks? 

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new spring is the way to go (stress cracks in old spring) for the cost of a new spring and the time, trouble and fuel of shaping and heat treat I would seriously consider the spring shop. 

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Charles, 

i have a new spring to work with for the "Rusty" option. I figured out a good while ago that it is not worth it messing with a scrap spring for this type thing. You can't buy a rebuilt face for the $100.00 you would save. 

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$100? New trailer springs run 1/2 that, lol. I do know that suspension shops some times use presses to rearch springs, but other than gaining a cuple inches lift in a new truck I wouldn't recomend it for a hammer. 

 

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that is probably the first time ive seen  a third world smith using a London pattern anvil. And damaging it.

                                                                                      Littleblacksmith

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There was a fellow extolling his method of making swords by taking a sledge hammer and flattening a leaf spring cold.  He was talking about how strong there were---which is to be expected as they ended up several *TIMES* heavier than medieval and renaissance using swords.  The possibilities of catastrophic failure with the cold work plus the unknown fatigue state of a used leaf spring were great enough that I guessed that the folks spreading the link for his video were probably liability lawyers... 

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Charles, 

So where would someone get a "Champion" style spring if he wanted to order one? I figured (not knowing any better) that you could have a spring shop that started with flat spring stock arch the flat spring stock to the right shape. I am thinking this may be one of the items to add to my list of thing I don't really understand. 

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I would imagine a spring shop would be the place to go, they generally have a large blown gas forge and a heat treat furnace, plus eye benders, punches and gigs (not to mention small parts and "U" bolts or benders to make them). If you can lay hands on a blue print, or mesured drawing it would be best, leaf length, leaf thickness, leaf count, leaf end shape as well as number and placement of shackles all come into play. Now remember this is an old mechanic not a power hammer engineer talking, so I can't speek to the oscillation rate of power hammer springs, and at what point they "foster", if you have ever seen the front tires on an old 3/4 ton Econoline (drove one at the right speed to experiance road tramp) you know what I'm talking about. 

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The spring shop in Anchorage I used to get drops from cold arced leaf spring from NEW stock. They didn't re-arc springs at all. You can hear the forge running in the back ground of the video, that spring may have been normalized or even annealed but the rust and wear spots makes me doubt that.

Frosty The Lucky.

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Would a small trailer springs (26" eye to eye) taken apart and put back together in the "right" way work? I think I could get that pre-stressed but it would not be the same shape as proper "Champion" spring. Is that worth messing with? I showed my wife how the tire hammer linkage worked and she commented it made her dizzy. 

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Do you have a picture of the hammer with the spring? If so, get a pair of calipers and take a measurement of a part you know the correct dimension for. It's pretty straight forward to interpolate the dimension of the part you need. Yes, that's plenty good enough these hammers weren't made to  space ship specs a good eyeball is close enough for a lot of it.

Frosty The Lucky.

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Frosty, 

I think I understand what you are saying. I am about 95% set on using a "krusty" style spring until I can get a larger work space but here is the plan for "the next one". 

Get small (24" ish eye to eye) 3 leaf trailer spring. Reverse the leaves and (maybe) use a come along tool to get it to the right shape. The funny thing is I work in Huntsville where a good chunk of what happens is rocket science so I should know better. 

On another topic, I have used the sage advice of Thomas Powers (on account of he knows many things) and have been gifted some forklift forks that I plan to cut up in to manageable chunks using a portaband saw (lenox bandsaw blades 24 tpi) and the angle grinder with cut off wheels. This will give me what I needed to upgrade to either a cut-off saw or larger grinder namely a good excuse. My portaband saw goes up to 420 fpm, am I correct that on something like forklift forks I want to go no faster than about 200 fpm?

I hope to get some of these chunks over to the local forge group for iron in the hat so the new folks don't have to resort to an ASO.

Thanks for all your help,

 

Ernest

 

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One quick follow up, can a carbide reciprocation saw blade (like for cast iron) be used on forklift forks?

 

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10 hours ago, eseemann said:

One quick follow up, can a carbide reciprocation saw blade (like for cast iron) be used on forklift forks?

 

Probably, but it would be slow going.  Better to use a metabo style slicer wheel on a grinder.  If you can get a real Metabo (they aren't cheap) it's well worth the investment.  Otherwise a good grinder and slicer wheel will be a lot faster.  Wear your safety gear.

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JM, 

Thank you for the information, I have seen metabo products on different websites and they seem to work and not be cheap but they work. my planned PPE is would be auto darkening welding set to grind, ear plugs, n95 mask jeans, long sleeve welding shirt (fire resistant but i have not tested that) and leather shoes. Do you think that will work? 

And a large fan so I don't pass out from having long sleeves and jeans on in Alabama in July! This is my find 

KIMG0204.jpg

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Almost the forklift forks we make (and I work for the largest manufacturer of forks in the world) are 4140 or 15B30. I have cut planty of forks in a metal cutting band saw with a good Lennox bi-metal blade. I'm sure you can get something close for a Sawzall, or even a hacksaw if you have extra time on your hands. They aren't anything super exotic

Brian

 

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Brianc, 

Thanks for the information, I will give it a try. The band saw is a good nicer to work with than the angle grinder. 

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Follow THE Rule of Saw Blades, "3 teeth on the work at all times." Unless those forks are 1/8" thick 24tpi insanely too fine a blade. The cuttings will gall and jam that puppy in no time, you'd have to feather it into the stock to give it any chance of clearing. you might as well use a hack saw.

Use as coarse a Bimetal Portaband blade as you can find and don't give it full throttle unless it's working properly full out. Your Portaband is a variable speed isn't it? Mine is and it was old when I bought it at auction 30 years ago. I haven't bought Portaband blades in a long time, still have some from the auction. You can get away with variable TPI that are way finer than the rule wants.

The other rule of saws. "Listen to it!" I've never met a saw that didn't tell you EXACTLY how it was cutting, if you're hogging it too much, not enough, when it was about to fail, just skating, floating on cuttings, etc. It doesn't matter what it's cutting be it a chain saw cutting through an auto body to rescue someone or a jeweler's saw cutting 24ga. silver, a concrete saw, composition blade or dry saw, mill saw or. . . They ALL sing their hearts out to you, you just have to listen to the music.

Frosty The Lucky.

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Frosty. 

As always I am happy to get information from you. The thickest part of the forks are 2" on the shorter end and 1 3/4 down to a bit less than 1/4" at the end of the taper. My saw has a speed control and I will take your advice. 

 

thanks 

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My pleasure, Dad would be happy to know I'm passing things along.

Next time you see Travis Taylor tell him Frosty is a fan and waiting for his next novel. :)

Frosty The Lucky.

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