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Making Bed Springs


MissyBoling

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MissyBoling

I've spent the last few days drawing up a plan for a set of bed springs replicating the springs on my mothe's childhood bed from the 1930s. The estimate for having the springs (204 of them) custom made was close to $1000 due to the machinery set up time for each type of spring. Soooo, I spent yesterday researching how to make my own springs. Due to the large quantity, the method needs to be efficient and consistent in results. I'm not too concerned about the large compression springs, but the tiny extension springs will be a problem. Due to the extremely small inside diameter, the mandrel will need to be so thin that it may not support the process of winding the wire around it. My other main question is whether the music wire needs to be stress relieved by heating after the spring is formed. I've gotten a lot of conflicting information about that, and about the method of doing it. One spring manufacturer said that music wire specifically needs to be heated to 500F for 30 min after the spring is formed. Another source said that anything over 350F for 20 minutes is overkill. Then there are those who insist that it's not necessary to stress relieve at all. I'd appreciate any thoughts on this.

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Perhaps purchasing some centering springs used in model train couplers would be an option.  Attached in a pic of two different sized springs I have used. One has an interior diameter of 1.5mm and the other is 2mm. Both are 5mm in length. There may be even smaller ones available.  These are compression springs so a coil would have to be made into a hook to be used as a tension spring.

Here is the link to the company. http://www.kadee.com/htmbord/page846.htm

Cheers, Guy

springs.jpg

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MissyBoling

Thanks Guy, this is a great resource. Unfortunately, these are still too big for the extension springs in this particular project, but they could be very useful for other things. ?

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Peter Jensen

Missy - Why don't you start by telling us the dimensions of the extension springs you are trying to replicate?  Inside diameter of spring, diameter or wire gauge of the wire, length of the coils when not in tension, distance between connecting points, and size of connecting loops.  Also whether you are most interested in having the springs be accurate in scale, look appropriate to the overall scale, or function with a springiness that seems appropriate.

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MissyBoling

Extension spring dimensions: (These springs will connect the large compression springs to each other.)

  • wire diameter 0.008" (0.20mm)
  • outside diameter 0.042" (1.07mm)
  • inside diameter 0.026" (0.66mm)
  • overall length, including loops, 0.26" (100 springs), 0.45" (40 springs), and 0.7" (4 springs)
  • the inside diameter of the loops needs to be a minimum of 0.017"

These are the dimensions I figured when I was still hoping to have them commercially made. This would be extremely close to exact scale replication of the full size springs. How close I can get to this doing it by hand, I don't know. 

Look, function, and accurate scale are all equally important to me. The springs will need to support a mattress likely filled with beads or sand, so they will be under a certain amount of constant stress, and they will occasionally have giant fingers testing their springiness. 

For an inside diameter this small, the winding mandrel would likely need to be about 0.02" (0.5mm), so the mandrel will be too flexible to support the winding process as it's usually done. 

I'm planning to experiment with a modified version of this method to see if it will work. The use of the tube should provide the support to the mandrel and keep the coil size consistent. Soooo, that's my thinking so far. What is actually possible to do in reality remains to be seen.

 

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Interesting video.  I too am interested to hear how your springs go ....

 

FWIW, Dritz glass head quilting pins are about 0.019" diameter.   While they are probably more flexible than desired, they are more resilient than many other mandrel possibilities.

 

Crystal Glass Head Pins

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  • 3 months later...

Stress relieving coil springs increases their life; that is, the number of times they may be used before they break in fatigue.

I doubt that it is important for a miniature which will rarely be used.

I first learned about this in a metallurgy class, perhaps 1962. Hazy recollection was an hour at maybe 400F, my class notes have disappeared sometime over the last half century.

Then in 1996 I was talking to a maker of miniature firearms. He had made a miniature Uzi, for Colonel Uzi, who at that time was living in Bucks County, Pennsylvania. Uzi told him the same thing about springs (coil springs in an Uzi firearm), to stress relieve them about an hour at 400F.

For some time I thought this very interesting but could not figure out what it did.

Then OH - a coil spring under compression . . . it is a long metallurgical story but yes, relieving those residual stresses from forming a spring improves its life. Once I got my brain in gear I realized I have seen one irritating failure caused by those residual stresses in a coil spring, and am aware of how to stress relieve the steel. Has nothing to do with making it softer.

About this time in the conversation my wife would be making "T" symbols, and slashing motions across her throat.

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  • 2 months later...
MissyBoling

Hi Gerry! I see we're going to be in class together in Castine. ? I took a detour from this project to work on some other things that had a deadline, so I haven't actually tried yet, but music wire is what I have on hand to use. 

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  • 3 weeks later...
MissyBoling

Thanks, but I've got a good stash of music wire. Are you just experimenting, or are you making something? Looking forward to seeing you in Maine! Bought my plane tickets today. 

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  • 2 months later...

Hi Missy,

Looking for a different wire type and came across .006" diam .152 mm music wire/ spring wire. Wasn't sure how fine you had found:

http://www.travers.com/wire/p/87454/?keyword=music wire

And a maker of tiny springs:

http://www.drtempleman.com/coil-springs/miniature-springs

The above also sells tiny springs, compression conical for just over a buck each, compression pricier at $3+ for tiny

A truly excellent description of making tiny compression springs using a small lathe:

http://www.deansphotographica.com/machining/projects/springs/springs.html

And a three part that also mentions straightening the music wire before coiling if it was previously coiled:

http://firearmsdesigner.com/?p=247

torsion spring: http://firearmsdesigner.com/?p=276

I'd love to see pictures of your spring progress!

 

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ElgaKoster

Lynda thank you for all the links, I am saving the website that sells them, you never know when I might need some.

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MissyBoling

Lynda, thank you for all the great information! I'm also saving the website that sells springs. I may be able to use some of the conical ones, but I'll have to check my measurements to see. 

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