Bending leaf springs

[whateg0]

I am working on a scale version of a old roadster and want to incorporate leaf springs. I have some old leaf springs from a pickup frame that I scrapped and would like to use them. I have heated and bent spring steel before, but never tried to reuse it as a spring before. What I intend to do is cut the spring into narrower, shorter strips and then roll eyes in the ends. It isn't going to be a high-speed kart or anything, so I can't imagine, if it broke, that anything catastrophic could happen. I just want it to look good, and have a working suspension.

Any advice? Is heating and bending the spring going to hurt it such that it would just snap off? I've made slappers from leaf springs and haven't had any trouble with them, but they are a little wider and I don't think I am using them that hard.

Dave

[SidecarFlip]

That's a loaded question (pun intended). When you heat alloy steel, especially sprigs, you change the molecular structure. I'd suggest making your springs from old stock springs and then taking them to a heat treater and having them atmosphere treated for the properties you want. It's cheap.

Note...heat treaters can take a sows ear and make a silk purse. It's all in the furnace application and controled atmosphere....

[ptsideshow]

You didn't say what size, but from the sound of it. You might try Tractor supply or Northern for there trailer parts for springs. As some of the spring sets are 2 feet long or so.

If you have a spring rebuilding shop near you take the info in for a quote. They generally are reasonable on repairs or building new ones and they would be ready to bolt on out the door. And they might be able to start with the ones you have.

That is unless you what it to be a built it all myself kind of thing.
:D

[whateg0]

There are actually a couple of spring shops here. And more than a few trailer supply places. I'm not after a spring of that size. This is going to be put on a small go-kart sized version of an old roadster. I'm not looking to spend a fortune. I had actually considered using a piece of strap and then attaching it to a hidden spring, but then remembered having a bunch of leaf springs saved for "just such an occasion". I guess if it's going to require very much effort to keep it from breaking, I'll just make a small A-arm suspension and use some valve springs. I think I will call one of the spring shops just to see how much, though.

edit: This spring will probably end up being in the neighborhood of 3/4" wide x 12" long, so there are probably no COTS parts that will work.

Dave

[vicegrip]

The science behind this is:
You can certainly heat and bend (curl) an old spring to
what-ever shape you need (want).
The area you heat, will assume hardness properties
relative to the last heat and cool-down you do on it.
You could then do a deep draw to say bright blue.....
and have good results.
===========================

Much like welding, the region where your heating meets the unaffected
remainder of the leaf-spring, will be "in question".
Call it the HAZ , and similarly the more abrupt the transition was
thermally, in your last heat, the more uncertain you can be
of the quallities of this region.

In an application where the spring isn't loaded to a point anywhere
near it's deformation range, it's not likely to be a problem.
The other factor is cycles or flexing, in a hobby or recreation use
you aren't likely to stress the HAZ area enough times for a failure
to occure. In an industrial application 100's of thousands or cycles
will reveal the weakest point.
vg

[SidecarFlip]

.....one reason I never fool with leaf springs....I tend to overload everything. Must be the steelhauler in me.....:p

Airbags are my friend (and overinflating tires)

[usmcpop]

Dave,

I have a whole bunch of Thai machetes made of spring steel. Each one was hand forged from a chunk of steel that was hot chiseled off the momma spring. This was done in a charcoal forge and there's a hardening line about 1/2" x 12". You can heat, quench and temper something that small without too much trouble if you want to bother.

Ping me and I'll send you one of those knives so you can see. As we say down here, "Ain't nothin' but a thang." :D

[vicegrip]

Dave,

I have a whole bunch of Thai machetes made of spring steel. Each one was hand forged from a chunk of steel that was hot chiseled off the momma spring. This was done in a charcoal forge and there's a hardening line about 1/2" x 12". You can heat, quench and temper something that small without too much trouble if you want to bother.

Ping me and I'll send you one of those knives so you can see. As we say down here, "Ain't nothin' but a thang." :D

I have some of these, D!ck sent a few years ago.
Who ever forged them did so close to "net" shape.

In America invercely.........
the old saying was;
"He who would a good egde win .... must forge thick and grind thin".
Spring science is a fascination, in and of it's-self.

Back to brass..........
I'd make yer Idea.... bet it'd be fine.
Phil

[SAWDADDY]

Brownells offers a line of books, gunsmith kinks or gunsmiths oops or something, used to have some but got lost in moving I think. Great books with tons of practical info that can be applied to anything metal. And chapter after chapter on making & modifying springs. flat coil torsion whatever. Plenty of info on home style tempering, anything you could imagine for a spring they had 10+ ways to do it all called out in simple langauge anyone with a tech background would understand.

[Thurman]

I've done my fair share of leaf spring "re-arcing" for round track racing applications. I've never used heat on any of them. I've always used two pieces of railroad track welded side-by-side at the bottom flanges, the use the open space between the two track pieces to lay the spring on and beat the heck out of them with a very large sledge hammer. I've actually curled them backwards somewhat. As far as rolling new "eyes" into the ends: I just don't see a way without heating them, and then I would think this would become the weakest spot.

[walker]

You can roll eyes in a localized heat, but then you must heat the whole spring to orange an quench in water. Go to your local spring shop and watch them make a few, or look on you tube for videos on making springs. Not too tough, need to educate yourself on color/temperature changes in steel, a lot of people are chicken about making springs. Once you watch the pros do it it might make you feel a little easier about doing it yourself. Also, you need a forge to do this, not a torch. You can make one with high temp fire brick and a propane burner though.