# Springs not bouncing back



## Maplehead (Jan 2, 2022)

Hi All
I have to buy lots of these 10mm x 30mm medium load springs because after pressing just one pickup cover the springs lose their original shape and don't bounce back, (as you can see in the pic). Do I need to go to a heavier load spring or is there a better alternative? I don't want to have to re-make all my die plates as they took forever to mill.
Any and all help and advice is greatly appreciated.
(Picture showing just the top two plates of my die jig.)


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## Aukai (Jan 2, 2022)

Are they coil binding?


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## Maplehead (Jan 2, 2022)

Aukai said:


> Are they coil binding?


Are you asking if the coils are catching to each other? If so then I would say no.
Here's a before and after pic.


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## markba633csi (Jan 2, 2022)

I think you need a much heavier spring with fewer turns


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## Aukai (Jan 2, 2022)

Coil bind I'm thinking about is too long of a spring, and coils getting compressed before the halves come together.


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## DAT510 (Jan 2, 2022)

Looks like you are exceeding the elastic range (in compression) of the springs and ending up with binding (Plastic Deformation), too long.    

If you look here at the McMaster Carr site, you can see the compressed length of the springs at "Max" load.  (Max load is the the load they can see before binding.









						McMaster-Carr
					

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.




					www.mcmaster.com


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## JimDawson (Jan 2, 2022)

OK, that's a new one.  In 45 years of building dies I have never seen that before.

Best guess is that the springs are too short (or too long) for the job, and you are pressing them down hard to complete collapse.  There is a max compression spec on the spring, expressed as a percentage of the spring length.  It could be that your spring pockets are not deep enough.   I assume you are using shoulder bolts to keep them aligned?


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## Maplehead (Jan 2, 2022)

JimDawson said:


> OK, that's a new one.  In 45 years of building dies I have never seen that before.
> 
> Best guess is that the springs are too short (or too long) for the job, and you are pressing them down hard to complete collapse.  There is a max compression spec on the spring, expressed as a percentage of the spring length.  It could be that your spring pockets are not deep enough.   I assume you are using shoulder bolts to keep them aligned?


Here are pics of my set up. Don't know if it helps or not. The purple sticky is pretending to be the .020" nickel-silver blank.


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## RJSakowski (Jan 2, 2022)

I've not worked with die springs but any compression springs that I have worked with are able to be compressed to solid height without deforming.  However, if the the tooling setup would allow compression past that point, telescoping one coil within another, the elastic limit would be exceeded and the type of deformation you are seeing would occur.  The press is capable of supplying enough force to do that.


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## woodchucker (Jan 2, 2022)

Couldn't you redo it without springs, and make it use pins, and the pins become ejection pins.


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## pdentrem (Jan 2, 2022)

We stamp lots of thin strip materials, no drawing jobs. We build our dies with 4 of 3/4” diameter OD 3/8” ID Green die springs 1 1/2” long with a collapsed height of 1 1/4” for the stripper plate and use ejector pins usually 4 to push the knock out to push the part out. 






						Industrial Supply Equipment from MSC Industrial Supply
					






					www.mscdirect.com


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## JimDawson (Jan 2, 2022)

Took me a bit to understand the pieces here, but I think  I have it figured out.

OK, I think  see the problem.   You need to add shoulder bolts through the springs.  So they would go through the punch holder, through the springs, and be screwed into the top stripper plate.


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## Nutfarmer (Jan 3, 2022)

Are you using wood dowels for leader pins? If so that would allow parts of the die assembly to move all over.


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## Maplehead (Jan 3, 2022)

JimDawson said:


> Took me a bit to understand the pieces here, but I think  I have it figured out.
> 
> OK, I think  see the problem.   You need to add shoulder bolts through the springs.  So they would go through the punch holder, through the springs, and be screwed into the top stripper plate.
> 
> View attachment 390671


I'm not understanding the bolts within the springs. How do I compress the plates together if there's something rigid there inbetween them?
Right now the top and bottom ends of the springs sit in 1/4" deep holes in the upper and lower plates.


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## Maplehead (Jan 3, 2022)

Nutfarmer said:


> Are you using wood dowels for leader pins? If so that would allow parts of the die assembly to move all over.


Yup, the metal rods helped keep the plates stuck together after pressing so I moved to wood. There doesn't seem to be any issues with the wood guide rods.


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## pdentrem (Jan 3, 2022)

The shoulder bolts will allow for the spring to compress. I will have to find a diagram.


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## pdentrem (Jan 3, 2022)

This is closer to what you would have in an industrial situation. Complex build.
Pierre


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## woodchucker (Jan 3, 2022)

Maplehead said:


> Yup, the metal rods helped keep the plates stuck together after pressing so I moved to wood. There doesn't seem to be any issues with the wood guide rods.


Odd, were you using hardened pins, or soft rods?  Hardened pins would have been the way to go.


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## JimDawson (Jan 3, 2022)

Maplehead said:


> I'm not understanding the bolts within the springs. How do I compress the plates together if there's something rigid there inbetween them?
> Right now the top and bottom ends of the springs sit in 1/4" deep holes in the upper and lower plates.



I drew this up real quick.  Maybe it will make more sense.


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## Maplehead (Jan 3, 2022)

JimDawson said:


> I drew this up real quick.  Maybe it will make more sense.
> View attachment 390716
> 
> 
> ...


Ok, I get it. The top plate rides down the bolt. Gotcha. However, what do I need them for? I don't think my springs come out of alighment or their respective holes they reside in. They just don't come back to full shape.
Also, thanks for that drawing.


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## Maplehead (Jan 3, 2022)

woodchucker said:


> Odd, were you using hardened pins, or soft rods?  Hardened pins would have been the way to go.


Just 1/2" mild steel rods. I don't think a little bit of play in my guide rod holes is affecting anything. The covers punch out nicely. My only issue is the springs not returning to original form.


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## Maplehead (Jan 3, 2022)

Now if I could just get the punch to knock out the holes and press in the D logo, but that would take me a year to build.


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## JimDawson (Jan 3, 2022)

Maplehead said:


> Ok, I get it. The top plate rides down the bolt. Gotcha. However, what do I need them for? I don't think my springs come out of alighment or their respective holes they reside in. They just don't come back to full shape.
> Also, thanks for that drawing.



The shoulder bolts through the springs keep them from deforming as you are experiencing.  Also attaches the stripper plate to the top die holder for ease of handling.


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## Maplehead (Jan 3, 2022)

One other question.
Any ideas on how I can minimize the pinching effect on the top ends of the covers?
(arrows pointing to them in pic)


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## Maplehead (Jan 3, 2022)

JimDawson said:


> The shoulder bolts through the springs keep them from deforming as you are experiencing.  Also attaches the stripper plate to the top die holder for ease of handling.


I'll add them and see what they do. I like that it makes less assembling.


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## pdentrem (Jan 3, 2022)

There is extra space in that area and metal is moving into it. Need to either fill that space by reworking the die or more force required to really pinch it tight. Another way would be reduce the thickness of the metal in that area prior to drawing it.
Pierre


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## Tozguy (Jan 3, 2022)

Pinching and bent springs are related. Springs are coil binding and preventing the die from closing completely.
I'm with Aukai


Aukai said:


> Coil bind I'm thinking about is too long of a spring, and coils getting compressed before the halves come together.


Need to change the springs for some with enough travel. Might need deeper seats for the springs.


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## Maplehead (Jan 3, 2022)

Tozguy said:


> Pinching and bent springs are related. Springs are coil binding and preventing the die from closing completely.
> I'm with Aukai
> 
> Need to change the springs for some with enough travel. Might need deeper seats for the springs.


Yup, I can see that, or like somebody else said, same length but less coils. Very hard to find.


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## markba633csi (Jan 3, 2022)

I said it.  And part of the problem is you really should have started with a larger diameter spring- more design flexability


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## aliva (Jan 4, 2022)

Perhaps a close fitting guide pin thru the id of the spring may control deflection. You'll have to bore a corresponding hole on the die plate.


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