Road springs

[Derek Sheldon]

Is there any used for used road springs or is it a case for the scrappy

[Hugh Barnes]

Dont be too ready to bin them. Imperial dimension steel for spring leaves is now unavailable. The material can always be reset and longer leaves cut down to smaller leaves thus losing the wear portions. That's my approach, anyway...

[David Cochrane]

And if the wear isn't too bad, you can grind/polish out the 'steps'. I did that on my Chummy about 40 years ago and they're still going well...

[Chris KC]

The main reason I keep mine is that a scrap spring can be very handy if you find a broken leaf. 
Those with blacksmithing aspirations can turn them into decent knives I gather.
And I'm sure it says somewhere in that panel beating book I lent to Hugh that old leaf springs are favoured for making panel slappers.
One thing is for sure, decent quality steel isn't going to get any cheaper.

[Bob Culver]

It is interesting to reflect that until about the 1860s high carbon steel was a very valuable commodity. Wrought iron was known from about 2000 BC but it was the development of steel ie hardenable "iron" which heralded the iron age, about 1200 BC,  although it took near 1000 years to cross Europe to Britain. Peasants did not have swords because were so expensive. Steel was extensively hammer welded to less expensive wrought iron to provide cutting edges. A solid carbon steel axe head or old leaf would have been very highly prized, though now of little more value than soft mild steel. Many old axes had just a hard edge.
Myriads of guys make custom knives; mostly from car leaf or coil springs so despite all the b.s. and fancy prices they do not really know exactly what made of or the optimum treatment.
In the  1950s broke a leaf in our Seven. The spring maker gave a great spin about the art of hardening and tempering. After a week the short top leaf bent up and stayed there. My father was not impressed.
A broken rear main can be serious in a Seven. The cracks are usually very evident for a very long time prior (unless hidden by gaiters)
Broken springs were common in all cars. A springmaker told my father that oiling the springs was the main cause!. But before very effective ling lived hydraulic s.as. May have been just carbon steel and not alloyed.

[Andy Bennett]

My pet niggle is the use of the phrase 'wrought iron' to describe anything that has some curly edges on it, when it is almost always mild steel. Wrought iron now is a prized commodity that is hunted down in reclaim yards and farm sales from old gates and used by the highly skilled to repair listed gates and such like.

As to blade making I have only ever made a few from layered mild steel (for flexibility and strength) and a harder steel for the edge. The high carbon steel can come from things like road springs or old files for really hard tool steel.

The real skill comes in the fire welding stages where the layers are welded together in what is quite a spectacular stage. Then the added skill is down to folding and layering to build up the strength and flexibility and ability to hold an edge.

I do get people wanting to 'make a chef's knife' on an experience day but I have to explain that the original course I went on for blade making was for experienced blacksmiths, took 3 days, and resulted in a 6 inch simple blade. What they end up making is something that looks like a knife but is actually a letter opener.

The likes of 'forged in steel' who make a blade from a single leaf spring in an afternoon are somewhere in between the letter opener and a 'proper' forged layered knife. That's TV for you.

[Chris KC]

How anyone can watch more than one episode of the TV knife series is beyond me . There must be a lot of very bored Yanks. Have also given up on the UK Repair shop series. 

Well there's something we can agree on Bob! I dumped TV entirely when they switched off the analogue signal and haven't regretted it for an instant. Social media may very soon go the same way.

[Andy Bennett]

Bob, you would be surprised how accurately you can work temperatures from metal colour. Whilst the colour is given a name, whether it is 'straw' or 'Cherry red', it is a colour recognised for its temperature rather than its straight literal interpretation. Cherry Red is even easier as it is also the point at which steel ceases to be magnetic so you can double check your visual estimation if you need closer accuracy.
Andy

[Bob Culver]

Thanks Andy. I had read that somewhere but not utilised so forgot. The hot colours assume subdued interior light as an old factory , a point not always emphasised. The temper colours are less debatable but the metal must be cleaned bright immediately before, another point often not emphasised.

[AustinWood]

In a former employment I worked on the development of laboratory furnaces. Testing them on site involved running them up to temperature (1000+ degrees) and monitoring the temperature.
On site at Harwell the customer would pop in from time to time to see how we were doing. He'd look into the furnace and tell us the temperature. He always had it right within a few degrees. Years of practice. He trusted his view more than our thermocouples and Wheatstone bridge.