Leaf spring, blue temper stock sources?

[gwrdriver]

IMHO a lot of it has to do with the proportions of the spring.
My first leaf sprung project used 1/4"x .032" in a relatively short (in height) stack but relatively long from hanger to hanger. Those springs were a bit stiff but worked OK. The second used 1/2"x .062" (plumber's snake) of relatively short length and those were like cast iron.

I recall that a common working compromise is to make leaf springs with alternating layers of spring steel and something dead, like half-hard brass or mild steel, or in England, a phenolic plastic.
I've never used phos-brz for leaf springs but based on its basic attributes I'm sure it would make good ones.

[Fender]

Spring steel at least in scale thickness is too stiff to work well.
A stack of steel leafs acts more like a bar then a spring.
Phosphor bronze is a much better material for scale leaf springs

Spring steel leaves that are scale thickness can be mixed with enough plastic (Delrin/acetal) leaves to achieve the desired stiffness. The plastic leaves add thickness to the spring stack, but no strength. Another strategy (although more work) is to “hollow out” the individual steel leaves so they have less stiffness.

[Rwilliams]

Long ago I watched a friend install a well worn blade on his bandsaw. He then got out his small angle head grinder and proceeded to quickly remove the teeth that remained on the blade while the blade was in operation. A great show of sparks. He than began to stop the saw and check the width of the blade that remained. A few more passes with the grinder with blade running around the pulleys had the remaining blade material at the desired width for the leaf springs he was going to make. The grinder was used to cut the blade and then the length of spring steel was taken to his shear where it was soon reduced to the desired lengths.

[Harold_V]

There can be a negative to using an old bandsaw blade. Especially if the wheels of the saw from which it comes are of reduced diameter. Blades that don't fail from tooth wear commonly fail from fatigue caused by the endless bending and straightening of the blade as it is routed around the wheels of the saw. The greater the wheel diameter, the less severe the flexing, resulting in reduced fatigue.

That issue aside, it should be understood that the back of the blade is not heat treated the way the teeth are. It is high carbon steel, but not hardened. That is so the blade enjoys a prolonged life, which it would not if the back was as hard as the teeth. You can thank induction heating for that ability.

H

[Bill Shields]

Acreed on the ph br....but if you are worried about $...??

[RET]

Hi,

This is a little bit off the original topic, but I think it is still worth adding.

Leaf springs are just one of the many things that don't scale well in our models. Fender gives one of the workable methods of overcoming this. If you use so called "dead" materials like sheet brass, etc. in most applications, the "dead" material will still contribute to the spring stiffness because as the assembled spring flexes, in most instances the added material will not be pushed beyond its elastic limit. By contrast, the plastic strapping (a good source for the "dead" leaves) is so flexible that it doesn't really contribute anything at all except the thickness of the dummy leaf which is exactly what you want. In addition, much of the plastic strapping is already black in colour. As a bonus, the plastic strapping is also already the proper width and thickness for 3 1/2" and 4 3/4" scale models.

An alternate method which I have talked about before in other threads is to put thin spacers between the leaves and to bend each leaf to a different radius with the longest leaves having the smallest radius and the shortest leaves having the longest radius. In a spring made this way, as the load is applied, each leaf will progressively add its share to the total load as the longer leaves bend and contact the shorter ones below. Very simple and very effective. KISS (Keep It Simple, Stupid!) strikes again!

The leaf springs on the main axles of the 3 1/2" gauge Boston & Albany tank locomotive I have are made in this way and they work very well. I can rock the locomotive from side to side (about 5 degrees each side of center which is a lot) and not one wheel will lift off the track! I learned this method from Harry Hawkins who was a member of the Toronto Society of Model Engineers and who built the Boston & Albany. I bought it from Harry and completed it, but Harry did all the hard work.

Those are the two methods I know of that work for models. What has been said before is correct. Make a spring that looks lie the full size one and usually it won't flex at all in your model.

Richard Trounce.

[Dick_Morris]

I got some .042 black Delrin sheet, cut it to 1/2" wide, and alternated it with steel leaves. One disadvantage is that the springs are probably more "bouncy" as the Delrin serves as a lubricating layer between leave and you lose the friction of steel on steel.

I got a lifetime supply of .042" by 3/8" and 1/2" steel when I bought 100' rolls a number of years ago. It cost more than I wanted to spend, but it's nice to be able to just go to the shelf and cut off whatever I need when I need it. The earlier stuff had nice smooth rolled edges, the later stuff is sheared and the edge isn't as pretty. some comes as blued and some comes bright, but a bath in chemical steel bluing takes care of the color.

All of the steel strapping I've seen is thinner that what it should be for scale springs. It's probably work hardened mild steel and not as good for the purpose of being a spring as true spring steel.

[SteveM]

I haven't been able to find it, but among the stuff my dad left behind is a roll of phosphor bronze. It's 0.005 (appears to measure slightly larger, maybe 0.0055).

I have several feet of it. More than I will use in three lifetimes.

It was tested with an analyzer, and I've included the analysis.

If anyone is interested, I will search for it.

Steve

[tetramachine]

I saw a listing for blued spring steel, in thickness up to
015. It was sheet, or roll.

Travers supply.