Well, my hobby budget is shot, dead, kaput, gone, non-existent for the unforseeable future but I really wish to make progress on some of my “To Do” projects. I’ve been working on a United/PFM 2-6-6-2 that I got in a box. I have re-soldered some parts, finished stripping paint, have made several screws on the lathe (very, very handy), and am down to the last hurdle, other than the gear whine. The front engine is missing all 6 springs for the axles. This creates some problems with derailments, mostly with the front axle, but I need to get them in there, and I must do it with materials on hand. Does piano wire , .025 I think, make suitable springs? I was looking to wrap the wire around a small rod (appropriate diameter), and while keeping the wire tight, heating it red and then cool it. I’m just wondering if this would hold up over time, or if there is another metal that would be more suited for this. Anybody try doing this? How well did it work?
Real piano wire is already a spring. It has been heat treated and tempered to the proper hardness to use as a spring. It will be tough to wind but can be done. You can heat it and quench it after you wind it but you will not have a spring at that point. It will need to be tempered (re-heating to a lower temp to draw some of the hardness out) which will give it a spring like tendency. Not knowing the material used in the wire I can not give you specific temps and times to heat to so some trial might get you there. I would try to make some first without heating to see if it can be done.
In addition to pike’s answer; .025" wire is way too big for locomotive axle springs; you need something on the order of .0025".
NWSL offers replacement springs for a reasonable price. Another alternative is the knuckle spring on couplers.
There is no need to heat the springs after winding, as piano wire is spring temper already.
After checking out my stock of wire, the smallest I have is .02 and you are right about it being too big. I was looking at heating it just to get it to form to the small diameter. I’ll have to check other options, including the coupler springs but I don’t know if they are strong enough. I have a variety pack of springs I bought years ago and will sort through and see if there is any with a suitable wire size and try reforming them. After that, I might try remotoring it using a donor motor and flywheel. I have really been getting into using the mill/lathe and may try making my own gears and boxes to eliminate some of the noise. I had this engine running for several hours on a small oval 18"r track and have decided it sounds like my truck, a turbo diesel, emphisis on the turbo whine, but on the good side it ran well.
A quick and cheap place I go for a replacement spring is an old click type ink pen, the spring in there fits many needs, and is generally long enough for several replacements.
It was done all the time back in the dark ages. You used something like a drill bit whose diameter was the core for the spring and you would two brass rods side by side to create the spring. When they were separated you had two springs. If this works for you I would then heat them and plunge them in a cup of water while hot to temper them
I have never had to make my own springs before, but I know there are some articles on the subject on this website listed below. It’s not a free lunch, though, because the website has articles on everything that could be made at home, so you will have to do some searching. Also, if you find the article I’m thinking of right now, you will have to adapt the methoods to fit your required spring size
For all the time and effort, not to mention grief, associated with such a project, there are a number of Internet sources available to buy different quantities and assorted sizes without breaking the budget. That’s what I would do and that is just buy a spring assortment for a couple of bucks and be done with it.