The Home Machinist!

I have used both spring steel and phosphor bronze for the leaf springs on my 1.5" scale PRR K-4. I used spring steel for the main leaf springs and phosphor bronze for the lead truck as I found the spring steel leafs to be too rigid for the lead truck. I had little success trying to machine spring steel. I ended up having my main springs cut and punched at Trainman's shop. I do not know what loco or scale you are building but phosphor bronze can be milled and drilled fairly easily and provides good elasticity properties for scale models. It is available from McMaster Carr.

I have also read where some Live Steamers have found that a full spring pack of reasonable scale is far too stiff. One common solution is to make some, perhaps alternate, spring leaves out of a plastic strip such as Delrin or Nylon. Both are readily available in black, some are also available graphite-loaded for low friction to boot.

McMaster-Carr carries all this, and of course, they have no minimum order limit.

Don't use Teflon; it will deform very quickly; think of the Teflon sold for valve packing material.

Holes can be drilled with a carbide spade drill. I did that with a 1/8-inch bit. Make up a fixture that's essentially a sandwich of two bits of steel top and bottom with the spring steel in the middle. Make a guide hole in the fixture, then drill through the spring steel. I did many leaves that way.

Milling a slot is a different issue and I offer no advice on that.

You could buy my dad's Waterbury Farrell benchtop punch press and punch the holes.

Not sure the capacity, but the company made a 5-ton that has a larger crank, so this is likely smaller.

Appears to have a 2" throw and 6" capacity under the ram.

Die sets we have found are 4" between the pins.

Not sure on what it's worth.

It's located in Southwestern CT.

Steve

Carbide will take spring steel. Like others have said, clamp it so it can't vibrate. Carbide likes feed, and by using a heavy feed rate it will dispel the heat into the chips. For smaller size tools, you'll need a good feel of the "limit" of the tool. Too little and the heat will work harden the spring steel, too much and it breaks off.

I successfully milled the slots in the top springs for my locomotives. Used a small 1/8" diameter 4-flute carbide end mill.
Also used plenty of lube oil and a constant feed rate. I did break one mill cutter learning the limits of the set up, but otherwise easily milled the slots in the spring steel.
~RN

NP317 wrote: ↑Fri Feb 02, 2018 11:36 am Used a small 1/8" diameter 4-flute carbide end mill.
Also used plenty of lube oil and a constant feed rate. I did break one mill cutter learning the limits of the set up, but otherwise easily milled the slots in the spring steel.
~RN

My experience with the 1095 spring steel and milling would seem to recommend a soluble oil over cutting oil. My carbide cutter cooled w/ True tap Aqua was still going strong after the job was finished whereas the carbide cutter with lube oil died after 21" of lineal cutting. My guess is the water component of the soluble oil was much more efficient at removing the heat and keeping the cutter cool than straight cutting oil.

HJ

Excellent tips for working with spring steel here for making leaf springs. I too have this work ahead of me. I assume all of the slotting and drilling of the center holes takes place before forming the leaves to the intended precamber radius? My plan was to make a hard wood former with the desired radius and bolt each leaf one at a time to the former and beat both halves or ends to match the radius with a rubber headed mallet. Does that make sense?

Thanks,

Rob

Rob Gardner wrote: ↑Mon Feb 05, 2018 11:26 pm My plan was to make a hard wood former with the desired radius and bolt each leaf one at a time to the former and beat both halves or ends to match the radius with a rubber headed mallet. Does that make sense?

Not exactly. If the leaves require a center opening, and it's created before forming, you'll discover that the bends will kink at the hole. Also, if you make the desired radius in your form, the resulting spring won't conform. It's going to spring back some, so you have to form around a smaller than desired radius, allowing for spring back. That's true regardless of how you form the spring, including using a die set in a punch press.

You might enjoy success by clamping the spring in the center, sans the opening, although I expect that it won't be adequate to prevent movement as you manipulate each side. It's going to want to rock side to side at the center point.

You might be better off to make a simple wooden (hard wood, like oak) die set and form the leaves using a large vise. A reasonably sized arbor press would be better.

H

You might be better off to make a simple wooden (hard wood, like oak) die set and form the leaves using a large vise. A reasonably sized arbor press would be better.

On some springs I used the curve from them being in a roll when received and it gave about the correct curve. You can also take your spring stock before you cut it into lengths and run it through a sheet metal roll. I also used a piece of pipe and a piece of wood cut to the same radius and an arbor press. Note that you have to over bend the stock by quite a bit if you use a die. I think the radius on my die was somewhere around half of the final radius of the spring. Note that the spring stock rusts easily and it's promoted by the oils and acids on your hands.

SUCCESS!! I used the wisdom of those that posted a reply to my question. Spring material "WILL" machine with the use of a carbide tool. Thanks to all. Michael