Making my first springs - what do I need to know?

I'm repairing an old musical instrument and need to replace 4 small torsion springs. Measuring one of the unbroken springs gives: wire diameter 0.5mm, 2 1/4
turns, inside dimeter 3.5mm, one arm about 22mm with 2 small bends in it, the other arm is about 11mm with 1 bend. I'm planning to take a naive approach and simply wind some piano wire around a 3.2mm mandrel, add the bends and then bake it at 250C for an hour or so. Will this work? How do I hold the start end against the mandrel?
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Winding a spring from piano wire of the appropriate diameter should do the trick, it is unlikely that you will need to heat treat it. Do not try to b e too economical with the initial wire length. Use a long enough piece to get a good hold on it at each end and try to keep some tension on it as you wind it. There are a number of designs of spring winders marketed to the instrument repair trade. While not worth buying for 4 springs, looking at the instruction pages for them might give some clues for your application, try having a look at Votaw Tools springwinder which has a video and manual for their tool: http://www.votawtool.com/springwinder.html . In the UK you can buy spare parts for many instruments from Dawkes Music http://www.dawk es.co.uk/index.php. They list springs and spring wire under repair materia ls and formed springs under spare parts. Their site has good pictures of t he spare parts so if your particular brand/model isn't listed have a look a t other makes to see whether there is something that looks similar that mig ht be adapted. I have always found them to be very efficient and helpful.
need other items such as reeds, lubricants or cleaning brushes if you deci de to place an order with them.
Good luck
On Sunday, January 4, 2015 9:07:01 PM UTC, no snipped-for-privacy@thanks.com wrote:

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Thanks for the reply. The instrument is an old East German Melodeon so I'm resigned to making the springs. The video at the votawtool link makes it all look as simple as I had hoped. I thought heat treating was needed to remove stresses and reduce the risk of failure ... but that's based on very hazy memory.
On 05/01/2015 11:08, Brassman wrote:


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On Monday, January 5, 2015 12:30:32 PM UTC, no snipped-for-privacy@thanks.com wrote:

I see that this company specialises in accordion/melodeon parts. Might be worth giving them a call. I have no personal knowledge of them though.
http://www.cgmmusical.co.uk/CGM_Musical_Services/Springs.html
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I just have a hole in my mandrels, but that wouldn't work for the arms. What about just tapping a small hole in the side of the mandrel for a screw? Might make a washer shaped to capture the wire if needed.
Pete Keillor
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These people specialise in accordion/melodeon parts. Might be worth giving them a call. I have no personal knowledge of them.
http://www.cgmmusical.co.uk/CGM_Musical_Services/Springs.html
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IMHO, heat treatment will result in annealing, so reducing the springiness.
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Springs are tempered to a higher temperature than cutting tools in order to avoid the brittleness that comes with the cutting tools' hardness. There's a
lower for tiny ones.
regards
--

Mark Rand
RTFM

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