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How to Make Leaf Springs

Tommy R

I wanna be Dave
Joined
Aug 19, 2008
Messages
4,271
Location
Austin, TX, USA
I need to make some leaf springs since what I need isn't commercially available. I went to a commercial grade lawn care store today to pick up a recoil spring from a lawn mower in hopes this may work for me. Well, the steel may work, but it's only 3/16" wide and I'm using the RC Brothers leaf spring kit made for 1/4" springs. I could make these work, but would much prefer to get the right spring to begin with.

So my questions....

1. Where did you get your leaf spring material? A store or brand would be much appreciated.

2. How did you go about curling the ends of the springs? I've got an idea in mind, but am nonetheless curious what others have done. :)

Yes, I searched, but was surprised to not find any more information on making leaf springs. I read to use lawn mower stater recoil springs, but not much more than that.

Thanks in advance!
Tommy
 
I've wondered the same thing. I'd read previously that the end is heated then curled with a needle nose pliers. I also read about using the recoil from a lawnmower and also from a nitro truck starter.
 
You can get spring steel (leaf spring material) from MSC or McMaster Carr. I don't have any experience heating up the ends, but sounds easy enough. The problem will be a holes that need to be drilled into the spring steel. Which you can imagine is really f**ken Hard RFH. A steady hand and a carbide drill bit should do the job. If at all possible use a drill press. The carbide drill bit is about 10-15 dollars. Carbide is very brittle so you may want to buy to drill bits just in-case.



Evan
 
I made mine for my clod scaler out of lawn mower recoil spring. It was out of a old b&s 5hp that had thrown a rod. It is the same width as highlift springs. To make the ends I just heated them till a dull red and gave a slight twist with a pair of long nosed needle nose pliers. Then heat and repeat till I got the eyelet finished. So far they have taken a beating on my scaler and are still going strong. "thumbsup"
 
A kind soul is mailing me some leaf spring material. Gotta love this forum! Anyway, I guess my next concerns will be to determine the best ways to curl the ends and to drill the holes.

I want to use 1/4" fuel line for the bushings so that will be my inner diameter for the spring ends. Figured I'd get some 1/4" rod and wrap the spring around the rod to form the loop. I assume it'll need some heat to do that.

For the drilling, I do have a drill press (and cutting fluid), but I'd read some people grind a hole instead of drilling and that worked well. I don't know what I'll do yet, but as always, I'm open to advice and suggestions. :)
 
i just made a pair of leaf springs yesterday, just used a mini torch and heated each end and bent it around but it works
 
So a kind soul mailed some spring steel to me and tonight I tried to make some leaf springs. I used my MAPP gas torch to get the end red hot, then tried curling it around a 1/4" screwdriver because that's the radius I'm looking for (so I can use 1/4" fuel tubing as bushings). Well, here's how they came out before I quit.

780415144_TtY9a-L.jpg


780415193_WyFtg-L.jpg


As you can see, I've got a few issues. First, any suggestions on getting a better rounded loop on the ends? I can't figure out a good way to do that. Secondly, I may need to get some arch in the springs. Any suggestions on the best way to do that? I tried just arching one of the springs and it kinked in the middle.
 
i made mine by not even heating and using visegrips and brakeline and my hands and mine came out great, and you just keep working around with the visegrips and bending with your hands and then when the gap closes then you can go around with the visegrips again making sure its good and round,

i will try to grab some pics to be a little clearer"thumbsup"
 
You're saying you bend the steel around the brake line with your hands....and a vise grip? I tried just bending the steel, but it snapped. So that's why I was trying heat.
 
i made mine by not even heating and using visegrips and brakeline and my hands and mine came out great, and you just keep working around with the visegrips and bending with your hands and then when the gap closes then you can go around with the visegrips again making sure its good and round,

i will try to grab some pics to be a little clearer"thumbsup"

"thumbsup" I did the same thing...here's some pics how they turned out on 1:6 WIP. Mine came out the perfect size for black nylon spacers I purchased at Ace Hardware, and the inside diameter is perfect for 3mm srcews.

http://www.scale4x4rc.org/forums/showthread.php?t=43773

Cobalt bits work good. I think I paid $8.00 for a pair, bought 2 sets. Used a center punch to mark and drill press for the holes...couple of things I found out, you should punch on something hard like an anvil, vise etc or the springs will crease when punched. Also, drill with something reasonably hard under the spring...I used left over 1/4 in aluminum. Clamp them down or you might have a propeller blade in your hands if the drill bit bites in.

The nice thing about buying a recoil spring is there is lots of it...usually 6 ft, either for new sets, extra leafs, or oops.
 
Nice build! Always liked CJ6's. :)

So can you elaborate at all on the method you used? I've tried wrapping the spring around the brake line and it seems nearly impossible. I've tried grasping it with the vise grips and bending it, but the radius was too large. As I tried to tighten it up, it snapped.

I just don't see how y'all are bending loops on the ends of this spring steel. Obviously, there's something I missing here... :|
 
Some 20+ years ago I made some leaf springs for a truck I was building. I used hack saw blades ground down to 1/4" wide. Here are some of the things that I learned.


1) High speed steel blades when bent too far will not return.

2) Bi-Metal blades will bend farther than high speed steel blades. "thumbsup"

3) Go Slooow when grinding blades down. Heat is your enemy, too much heat will take out the temper.

4) Heat your ends to a cherry red to remove the temper.

5) Clamp blade and bolt in a vise and start your bend using a small hammer wrapping blade around bolt.

6) Reheat blade to cherry red.

7) Finish bending blade around bolt.

8) Reheat blade to cherry red.

9) Adjust loop diameter as needed.

Your blades don't need to be red in color when bending, you are taking out the temper.

If you need any holes in your springs use a Dremel with a grinding stone or carbide burr. Pressure from drilling causes friction which in turn causes heat. See rule #3. Get some used dental burrs from your dentist. They are either diamond or carbide and small in size.
 
Anyone interested in more spring steel? I've been thinking about adding it to the website for purchase . The material tommy has is what I will be selling.
 
I have and still use the strap banding that is normally used for crating, it can be found in various widths and thickness. its easily cut with avaiation (tin) snips. I heat the ends to remove the temper.
 
Well, I may have finally figured out a good technique for curling the ends of the spring consistently. First of all, I wanted to use 1/4" fuel tubing for bushings. It fits a 3mm screw inside nicely. So the insider diameter of the leaf spring loop needed to be close to, or a little smaller than, 1/4". A screw driver or drill bit will likely be the right diameter to act as a die.

So put the "die" in a vice so it is held securely. Heat the tip of the metal red hot and place the end of the steel to the die. Grab the die and the steel with a pair of relatively small pliers and hold steady while pulling the other end of the steel to wrap it around the die. BE CAREFUL not to burn yourself! While the heat dissipates very quickly, it's not worth taking any risks. You may have to repeat this process a couple times before you make the entire loop. Just try to use as little heat as you can.

Here was the result of my first attempt.
786493785_t74DV-L-1.jpg


And this is with the fuel tubing in there.
786493641_Apqn8-L-1.jpg


I hope the process I outlined is clear. If not, let me know and I'll see about grabbing a couple pics to illustrate it better. :)

The next issue is how to put a slight arc in the springs. The other day I zip-tied one to a can overnight and it put a bit of an arc in it. A slightly smaller diameter can or maybe leaving it tied up longer and I may get the results I'm after....
 
Resurrecting the dead here, but is there now a general consensus on how to put an arc into the spring that will maintain its shape? I've just been heating them, then pushing it against a small paint jar with the radius I want for about 5 seconds. Seems to help.
 
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