What wire for spring and where from?

Dunno how effectively. You would need to temper as well as hardening.

Piano wire is OK, don't anneal it first though. I've wound springs quite successfully from piano wire on the lathe, it's an 'interesting' excercise. 3mm might be 'very interesting' They need tempering afterwards, a domestic oven will do for that. I can't remember the precise details, I think one place to find them is one of Guy Lautard's 'Bedside' books.

Should be doable with piano wire, though of course that will be prone to rusting. Buy it from model shops or piano repairers, though I don't think they actually use 3mm thick on pianos.

HTH Tim

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I have just tried as a long shot heating the wire to cheery and then quenching with no noticeable effect, still no spring left in the wire and a previous look through my books did not mention springs although I have a few books left to read.

Thanks for your response Tim

The 3mm was what I had to hand, ham radio antenna whips and the like.

Cheers

Adrian

Sounds like you've got an austenitic or ferritic stainless wire (i.e. not much carbon in it) which had its original strength from being cold-drawn (i.e. heavily cold worked). You can soften it by heating but it won't harden by quenching.

You're probably much better off nipping down to the car breakers and canibalising something off the pedals of a(or several) car(s). when i was into karting I used to use a tension spring an inch up from the pivot pulled back to a clamp on the frame - easy to tweak and easy to get. Richard

Congrats! You just discovered annealing, the art of making things dead soft. No real hope of getting where you want to go from that point. If you have any of the material left, try bending it cold. If it breaks, it would not ghave lasted in use anyway.

Most, if not all coil springs are wound around a mandrell cold. If you dig around, there are nomographs that use the wire diameter and a couple other variables to determine the diameter to use to wrap the wire around, in order to arrive at a particular diameter of coil.

Use piano wire from a hobby store that caters to the radio control airplane people. It's cheap, usable as is, and you get enough that you can experiment with a couple lengths to see how small a diameter you need to use to wrap it around. It is not full hard, and bends well, without breaking.

Cheers Trevor Jones

Hello.

Coil the springs cold, then heat treat depends on material but for piano wire 230 C for 20 minutes and air cool.

Piano wire is hard drawn, and ground and polished before final drawing process for really good quality surface finish, which equals good fatigue life. From memory, BS5216, and 0.70% carbon, 0.45% manganese I think!

Many larger springs were made from annealed spring steel (BS1449 if my memory serves me correctly), followed by conventional oil quench and temper to around 45 Rockwell C or Austemper to around 48 Rockwell C.

Worked in the spring industry for 14 years, used some exotic materials too, but for a go cart, the stainless should be fine, would heat treat a bit hotter, say 280 C but 250 C should be fine too.

Lots of maths around stress in springs, but with 3mm wire for a longer fatigue life, don't let the D:d (mean diameter to material diameter) ratio get below 3:1

Enjoy! Bill

I have found a website that describes the whips as made from 17/7 PH Stainless steel.

In my above tests I thought that that annealing could be reversed, but obviously not in this case, does anyone recognise the material.

I have some more at 3 mm and I will try to bend cold, but I will be using goggles, gauntlets and any body armour I can fashon!

Adrian

The PH in the name is for Precipitation Hardening. You are going to need a oven that has a very accurate temperature controller, and the appropriate information to determine both the temperature required, and the cook time to get the properties you need, IF the properties will suit the use as a spring. You are going to have to research that too.

Cheers Trevor Jones

IF the properties will suit

OK I will try to get myself some piano wire.

Adrian

I've found the reference, in Guy Lautard's first Bedside Reader, I don't think it's the main reference I used and may not be all that much help, but I'll gladly scan & email it to you if you wish.

Cheers Tim

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This might be useful:-

Tim Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

Tim

I have temp solved my issue at present, (not that nice looking) and next week will try to get some piano wire if time allows. I did a search on the web and found something, if I need the scans then I will drop you an email many thanks for the offer.

Adrian

I found that as well, about the only real link google came up with.

Adrian