heat treat for spring on slip joint

B

boltcutter

Guest
I just made my first slip joint folder. I want to heat treat the blade and wonder if i should heat treat the spring? It is made from 1084 steel. I also wonder why other knifemakers have said the spring should not fit flat and square against the knife tang and should only hit the blade tang a little on the top and bottom and not square and flush. I bought the Don Robinson book but he uses some other type steel and doesn't elaborate on the spring and blade fit. Thanks for any help.
 
Ok first question if your using 1084 and your making a spring HT it the same as the blade, then draw it back with a torch until you get a blue color from behind the pivot pin hole almost to the tip. This is for all non stainless steels
Second question, the spring is set like that to keep tension on the blade to keep it open.
 
I do what Rusty does but I temper the whole spring with a torch and I do it 3 times, quenching in oil after each heat. I also clean up the spring after each heat so I can see the color change again. I have never had a spring break by doing this.
 
thanks to all who replied. thanks for the book don robinson.
 
Here's another centuries old method that blacksmiths have been using for tempering carbon steel springs. After the spring is hardened, put it in a shallow pan and pour in enough oil to just cover it. In a well ventilated area, heat the pan and oil until the flame sustains itself. I use drain oil. When the fire goes out, the spring will have a perfect temper. I've known about this method of spring tempering for years and recently started using it for knife springs after I was reminded of it by another slipjoint maker. It works every time with no guesswork on tempering colors.
 
Last edited:
K R Johnson said:
Here's another centuries old method that blacksmiths have been using for tempering carbon steel springs. After the spring is hardened, put it in a shallow pan and pour in enough oil to just cover it. In a well ventilated area, heat the pan and oil until the flame sustains itself. I use drain oil. When the fire goes out, the spring will have a perfect temper. I've known about this method of spring tempering for years and recently started using it for knife springs after I was reminded of it by another slipjoint maker. It works every time with no guesswork on tempering colors.
Click to expand...

I've seen this done by blacksmiths to temper buggy springs as well so I know for a fact that it will work.
 
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