Shorten and de rate springs

I am restoring an old loader for my Ferguson tractor . The bucket originally had two hefty tension springs , about two feet long and two inches in diameter ,fitted to return it to the fill position after unloading . These have long been unavailable as spares .
I have two long tension springs from a garage tilt door , these are the same diameter and gauge but too long and far too strong .
Is there a way of de rating or weakening these springs and shortening them to fit without ruining its action ?
I can easily cut them to length but am completely ignorant of heat treating and tempering processes . Thanks .

If you"ve got one of the original springs, or know the specs on one, you can call someone like Lee Spring Co and have them custom make what you need. I needed some made special to enable me to rebuild the detent on some valve bodies, and they got them to me in a timely manner, and for a fair price.
That said if the guage of the wire on the door springs is to big to begin with, then shortening them isn"t going to do you much good. Basically when you shorten them you are going to basically make the spring stronger because you reduce the effective length. In other words the spring tension is just as effected by the length of the spring as it is by the diameter of the wire it"s made from, and the number of winds. That"s not to say that the tension wouldn"t decrease once you pulled the spring and"sprung" it, but in, or really close to, it"s original wind, it"s going to be just as strong regardless of how long it is.


Probably not what you wanted to hear, but if you want it to work right, given what your saying, it looks like custom springs are going to be your best choice.
Lee Spring Co.

Thanks for that , the length to strength ratio makes sense.
Lee Springs are a little too far from Southern Australia , but I think we still have the technology left to wind new ones . I will look for a supplier here .

(quoted from post at 19:31:30 07/11/14) I am restoring an old loader for my Ferguson tractor . The bucket originally had two hefty tension springs , about two feet long and two inches in diameter ,fitted to return it to the fill position after unloading . These have long been unavailable as spares .
I have two long tension springs from a garage tilt door , these are the same diameter and gauge but too long and far too strong .
Is there a way of de rating or weakening these springs and shortening them to fit without ruining its action ?
I can easily cut them to length but am completely ignorant of heat treating and tempering processes . Thanks .

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In answer to your question: For a steel coil tension or compression spring it's rate (force per unit of length change) is determined by; the diameter of the wire, the diameter of the spring and the number of coils. Heat treatment does not change the rate but merely allows it to stretch and return to it's orginal length, in other words - act like a spring. In summary if you were to shorten the springs you have found the rate would increase, the spring would become stiffer (stronger as you say). Note - if the springs you have are the same diameter and the same wire gauge as the Ferguson springs then they will have the same rate if you cut them to length.

Some things for consideration: use one spring instead of two, change the attachment point on the bucket or use a compression spring. To use a compression spring in tension, two U shaped bars are inserted (from each end) through the spring. The bars have hooks formed on the ends which seat on the ends of the compression spring. When you pull on the open end of the bars it compresses the spring. The springs of this type (smaller) are common on screen doors and porch swings in this country.

(quoted from post at 19:31:30 07/11/14) I am restoring an old loader for my Ferguson tractor . The bucket originally had two hefty tension springs , about two feet long and two inches in diameter ,fitted to return it to the fill position after unloading . These have long been unavailable as spares .
I have two long tension springs from a garage tilt door , these are the same diameter and gauge but too long and far too strong .
Is there a way of de rating or weakening these springs and shortening them to fit without ruining its action ?
I can easily cut them to length but am completely ignorant of heat treating and tempering processes . Thanks .

Click to expand...

Unless you are going for a "correct" restoration, you are much better off WITHOUT any springs. After dumping the load, simply drop the loader to the ground while going backwards, and the bucket will easily latch back into the fill position. Those springs are usually so stiff that the bucket will SNAP back so quickly and with so much force that any material remaining in the bucket will become airborne and land on the tractor hood and maybe even you.

What a nice source, Lee Springs ! Thanks NCWAYNE !

Thanks again all , Rustyfarmall, I am looking to restore it correctly but the advice on the snap back is really appreciated . I now know why they were removed at the farm it came from , they used the loader there for shifting chicken poo ! :shock: :lol:

(quoted from post at 15:38:29 07/12/14) Thanks again all , Rustyfarmall, I am looking to restore it correctly but the advice on the snap back is really appreciated . I now know why they were removed at the farm it came from , they used the loader there for shifting chicken poo ! :shock: :lol:

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Yep! The return spring for my McCormick #31 loader is hanging on the wall in my shop. My dad also had a #31, and the return spring for his was also hanging on a wall.