(Leaf) Spring Steel - CS70 / CS80 annealed state suppliers

[sis]

Hi,


I am attempting to purchase some spring steel for leaf springs. As I understand it CS70 is often specified but I am having trouble sourcing it at a resonable price. I know I can get it from reeves but its a bit pricy and in 24" lengths so there would be a lot of waste. I've contacted a number of industrial suppliers in the Sheffield area which can offer CS80 and in imperial sizes but only in the hardened and tempered state.

3/64" / 18 gauge - 5/8"
16 gauge - 5/8" and 1/2"

Can anyone recommend an alternative supplier?
If not can anyone advise on the process for annealing and/or hardening and tempering?

Alternatively how machinable is it with modern carbide tooling?

Thanks,
Steve

[jo479]

try ebay for spring steel, there is a chap advertises it, I have had several coils off him for loco springs

[jo479]

I had a quick look at my previous orders on ebay, the seller was Skywayta2010a118 , search for him, he has vast quantities of spring steel

[chris vine]

Hi Steve,

I have never softened spring steel to make leaf sprints. I find that it machined fine with modern carbide tools.
You can cut it with a sharp hacksaw blade if you take it slowly.

To my mind it is a lot easier and less likely to end in a broken spring to do it this way.

Chris.

[trainman]

I got the springs cut for my Britannia tender by Model Engineers Laser, they did a great job.

[sis]

Hi

Thanks to all those that have replied. I’ve got in touch with the ebay seller.

Good to know it is machinable with carbide.

I did not even conisider to ask MEL as it being carbon steel I had thought it not feasible to have it laser cut as gauge plate is I think not possible to laser cut.

Thanks
Steve

[92220]

The guy that took over Hewson Model Supplies sells CS70 in the annealed state. He also gives instruction for heat treatment after machining to shape. I bought mine years ago, from Doug Hewson, and machined the leaf sections with standard HSS cutters. If you want to check this guy, just Google D.Hewson Models. This comes up as the to[p listing. Just click on it and thie Doug Hewson catalogue cover page comes up and at the right hand side is a red box that say "Current Catalogue". Click on this and you get the available listings.

Bob.

[peterdanastas]

Try AJ REEVES or BLACKGATES

[sis]

Hi,

I contacted the steam workshop but they are still "looking for" what stock they have. AJ Reeves - only sell in 24" lengths which makes for a lot of waste and higher cost. I will write to Blackgates.

Thanks,
Steve

[ettingtonliam]

So what size are your springs and how many of them do you have to make?

[oldnorton]

Steve

Speak to M-Machine. http://www.m-machine-metals.co.uk. They have a web download PDF catalogue, that is not quite as readable as the old one, but p83 lists all manner of spring steel sheet and they normally guillotine your desired width.

In deference to others who like to work with the material as received, usually described as in a semi-annealed state, my practice is to anneal it first, then cut, drill, etc. and roll to shape. Then you separately harden individual leaves properly, quench in oil, and anneal to a pale blue in an available oven.

Norm

[millman]

Oldnorton I assume the “available oven” is the domestic oven when the wife is out shopping.

[Neale]

I tried making leaf springs for my 5" Black 5 tender. Machining and rolling to required shape was easy enough. Hardening - heat to red and quench - was easy. What was really difficult was trying to temper to the right colour uniformly. I thought that a sand bath heated from below would do the job but it is very difficult to make sure that the embryo spring is properly and consistently in contact with the sand. Very difficult to get the thing uniformly heated along its length. Too little heat and the thing stays remarkably brittle. I snapped a couple of them that had not been quite sufficiently heated. I'm not sure that a domestic oven gets quite hot enough. OK to temper carbon steel cutting tools which need something around light to dark straw, but not enough for springs. I have started making springs for the bogie, and I'm currently planning to use a bath of molten lead which I believe is about the right temperature and at least gives a chance of soaking for a few minutes at the right temperature.

Quickly coming back to the original subject - I found someone on eBay selling big rolls of annealed spring steel a touch overwidth that machined nicely to size. The seller was skywayta2010a118 (2087) (I note that he was already mentioned above) but that was back in 2019. £11 for a 1kg coil which is going to be enough to make all the springs I need about 5 times over. That seller still appears to be selling spring steel strip. Good luck!

[oldnorton]

300 degC for a dark blue starting to turn to pale blue, 310 degC is the stated figure for loco springs.

A bit much for most domestic ovens to hold. A lidded gas BBQ will get there.

I used a ceramic furnace with small, lidded clay pots to put the leaves in, but the temperature control of cheap ovens is not perfect.

A three inch depth of fine, dry sand in a biscuit tin, over a camping gas stove, takes a long time to come up to a steady state but you can measure with an IR gun and turn back the gas. The leaves can be pushed into the sand for contact and the edge exposed will show the colour - a few experiments first on scrap until it all settles then you can do lots all at once.

[Neale]

Don't have an IR gun so the idea of a very deep bed of sand hadn't occurred to me as I could not have measured its temperature. However, I discovered at my club night last night that I have a friend who does have one - might be going begging to him one day soon!

[chris vine]

I have to repeat my earlier reply: why go to all the bother and worry of hardening and then tempering when you can form/machine/drill spring steel in its hardened/ tempered state.
Modern tools make light work of it and you remove all the risk of breakage from getting the tempering wrong.
C

[92220]

I agree with Chris. The leaf springs on my 9F were all made from hardened and tempered spring steel strip. Any machining you might want to do is easy with readily available carbide milling cutters and twist drills. If you have decent industrial quality HSS tools, they will also cut the spring steel in it's tempered state, though carbide is always much easier, and quicker.

Bob.

[Neale]

It's a good point, and I'm not afraid of machining a bit of hardened spring steel given that I have CNC-milled HSS toolbits before using carbide tools. I'm sure that this probably sounds naive to experienced loco builders (which I am not - my Black 5 is my first) but I don't know how you can put a curve into ready-to-use spring steel. Is it that actually you should start with a flat spring and let the loco weight set it into an appropriate curve? I have been rolling mine to about the right curve before h&t operations and they look OK on the tender (just a couple of steel leaves plus tufnol to act as packing/dummy leaves).

[chris vine]

Hi Neale, to curve the spring strip in its hard state you could certainly roll it.
I made a curved former, male and female, and just pressed them to shape.
Either way, I think it’s best to over curve them and the bend back by hand a little until you have the desired curve. Maybe a little experimenting to get it right. If you don’t bend them back a bit. They will do it all on their own when you load them up for the first time!!
However, a little experimenting to get the desired curve is much easier than all the heat treatment palaces…
Chris

[oldnorton]

Jul 28, 2023 22:10:01 GMT chris vine said:

I have to repeat my earlier reply: why go to all the bother and worry of hardening and then tempering when you can form/machine/drill spring steel in its hardened/ tempered state.
Modern tools make light work of it and you remove all the risk of breakage from getting the tempering wrong.
C

Chris

Greatest respect for you, but I hope we can disagree as friends.

If you have made them that way, and are happy, then that is fine. But I am not content to advocate such a method to others.

How do you know in what state the steel is delivered? It is described as semi-annealed.

I know it is not fully hard because you can put a bend in it. That means that the loco's weight can deform it. I don't think that is how springs are supposed to be?

Norm