geekhack
geekhack Projects => Making Stuff Together! => Topic started by: abrahamstechnology on Mon, 24 September 2018, 09:40:27
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Hello,
I think a very good idea would be some sort of 3D printed press tool to uniformly bend worn-out Alps leafsprings back to their original shape. I have lots of black Alps that I would like to restore, but I fear hand bending them will cause inconsistencies. I am not good at 3D design, though.
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Bending springsteel back into shape relies on over-bending. The amount of the over-bending depends on the state of the spring. So the best way is bending them and inspecting until they are at the desired position. Perhaps you could make something to help with the inspection process? Or what did you have in mind?
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Ohh, I would be interested in this too. I have a lot of alps switches that need restoration.
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This will not work.
Spring properties change when you over stress them, which is needed in order to change them. Since each spring has been work hardened and stressed differently, bending them all to match will NOT result in an even tension or feel.
Restoring several used springs to match is actually a quite technical process and not something you will accomplished by just bending them to look alike.
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I could imagine some apparatus powered with something like a torque wrench might work. You bend them to whatever radius is needed to produce a specific amount of torque.
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I could imagine some apparatus powered with something like a torque wrench might work. You bend them to whatever radius is needed to produce a specific amount of torque.
It could, but while you can match one point in travel, you cannot make multiple springs match across their range of travel.
So let's use a Cherry red spring since it's easy to understand...
start = 30g
mid point = 45g
End = 55g
As they wear, the higher use ones will now read:
start = 25g
mid point = 35g
End = 45g
Now let's say you rebend the more heavily used to match the lesser used ones. While the lesser used are still normal, the tweaked ones now show:
start = 28g
mid point = 45g
End = 60g
Yes, you matched the mid point, but you cannot match start and end because the force curve has been changed. You can re-bend to match start or end, but you will mess up the mid point. You can NEVER match all 3 ever again, at least not without some serious equipment or melting them all down and remaking them again. Let's say you have that equipment though, you weakened the spring even more while bending it so it will fade even faster this time than it did last time and as it fades it will fade differently than it did before.