Types Of Metals Used For Tools

[Willem]

Old leaf springs are normally 5160 high carbon, newer ones EN24 or equivalent, and you are right - it is a good steel for knives. Main thing is to not over heat due to the relatively lowish carbon content (about .6) - but the heat treatment is very simple - heat in a fire or even with a gas torch until dull red going onto brighter red, test with a magnet - if the steel no longer holds the magnet, keep it at that temp for another minute or two, quench in old motor oil, stirring it around. Remove after about 5 or so seconds, and let it cool off in the air.

Sand off the oil, stick it in the oven at between 360 and 425 F and watch it from time to time, it will go a golden yellow, then brown, purple and then deep blue - at this point remove it from the oven and let it cool off or quench in clean water, sand to shiny and repeat. And that's it. Apart from putting it together and sharpening it, of course..

[BIGGUNDOCTOR]

Leaf springs would be hard to have professionally heat treated due to not knowing the exact steel specs. Some are 5160, some older ones were 1095, ya just don't know unless you get it tested $$$, or you can get the specs from the original manufacturer. Another issue is that some used springs will have micro cracks from years of use, not often ,but it happens. You can go the above heat treat route which will give good somewhat predictable results, but if you want guranteed results you need to get a known tool steel grade from a supplier. www.iforgeiron.com is my other hangout.