heat treating question

Ever read "The Complete Modern Blacksmith" by Alexander Weygers? He goes into quite a bit of detail about heat treating scrap such as car springs. It's a pretty common book in libraries. I believe I got my copy from Lindsay's. Gary Brady Austin, TX

" It remained to harden and temper the tap. I coated it with Joy dish-washing detergent, heated it to a "cherry red" in the forge and quenched it in mineral oil. I cleaned up a couple of places so I could see the colour and heated it on a lab hotplate to light brown. See Making_a_tap3.jpg. This is a nice way to temper small objects as the hotplate has a thermostat and is much more controllable that a flame. " This was drill rod but I use the same technique on OCS. For a tool such as you describe, you want it tougher and not as hard as a tap. The difference is just in the tempering. Heat to a dark brown or purple. These colour changes can be fool you: Nothing happens and then sudenly it goes really fast. For objects larger than my little hotplate can handle, I have a 4"x8" piece of plate with little legs that hang over the edges of my anvil. This helps to keep it in place. I heat this in the forge to red and then use it to heat the object being tempered.
Hope this helps.
Ted

You want a surface that you are going to hit with a hammer to be soft. You don't need dead soft so I would recommend normalizing. Heat to red and let air cool. The back end of a chisel is soft and you dress of the mushroom curls when they become dangerous. Stainless makes a good surface to hammer on. Something like a pad of 316 stainless will work harden as you hammer on it limiting the mushrooming. Randy
I want to make a hinge fuller out of old truck leaf spring. I figure I can cut them with a torch and grind the ends clean, and heat them in a forge and hammer them flat, and then do the shaping on a mill and belt sander. There will be 2 pieces both layed on their long edge, edge up. One will be welded down and the other will be hinged such that when it is in the fully down position it lays edgewise right on top of the other one. The top of the hinged piece will be hit with a hammer. I want to know the best way to heat treat the top surface that will be struck with a hammer. My goal is to have it tough enough so it doesn't mushroom right out under hammer blows, but not hard enough to chip.
I'm a total rookie at heat treating.
Anyone want to take a stab at this?
Grant Erwin Kirkland, Washington

I agree with Randy. Spring steel is way tougher than mild steel just normalized. It should hold up pretty well, especially given that you are hand hammering, not power hammering.
Steve Smith
R. Zimmerman wrote:

Unfortunately, yes.
Apart from being one of the worst books on smithing you could possibly find, he clearly doesn't understand heat treatment himself, let alone explain it.

Why don't you add another slab of steel to the fuller upper to whack on? After you heat treat the tool piece, (heat to 1575 degrees F and quench in oil, then draw to 400 degrees F) grind a flat spot on the back of the tool and arc weld on a piece of soft steel about two inches square by a half inch thick. Most old truck springs are at least two inches wide, so the local heating of the arc shouldn't affect the working face of the tool. It should take a While to batter through that, and you don't have to worry about damage to your hammer face, plus it's a much larger target than the edge of an old spring.
Happy whacking...
Charly

Don't forget he said he's a total newbie to heat treating.
+++1575 degrees F and quench in oil, then draw to 400 degrees F+++
English translation = heat until a magnet no longer sticks to it, dump completely in oil until cold (watch out for initial surface flash fire), wipe clean and set your home oven for 400 degrees. Bake for 1:30-2:00 and let cool.
Dan Crowther

Why not make a spring fuller out of a coil spring and not heat treat it. has worked for me for years Doug