Newbie Questions

[reefera4m]

A couple of questions those with more experience/knowledge.

First, I'm working with OFLSS (Old Ford Leaf Spring Steel) from a '78 Ford Heavy Duty Pickup, which I'm assuming is 5160 (maybe I shouldn't assume but can't confirm one way or the other). The first knife I made seemed to work out pretty good - I heat treated it and edge quenched first and them tempered at 400 degrees for two hours. The edge definitely hardened - a Nickleson file skates over the edge and when I lock the handle in my knife vise to polish the blade there is still some flex. The steel is quite tough to work.

I have quite a bit of this steel and I figure that at the least it would be good stock to begin with. I started out by making some blank stock. First I clean off the rust with a flap wheel (24 grit) and wire cup brush then cut to rough size with a cutoff wheel then heat it in my forge and straighten it.

My questions are:
1. Is there any benefit to removing the rust prior to working this steel or would the heating/hammering just reduce it to scale that i can knock off with a brush?

2. How much forge work of thinning/shaping versus grinding/sanding? Certainly hammer work is less expensive than grinding/sanding belts but is there a point that I can over hammer - assuming I stop before the blade becomes too thin?

3. Other than cooking out the carbon, is there a limit to the number of reheats/forging work I should be aware of and if so what would be the effect of too many reheats? I ask because this steel is tough to work and I've found that it is taking me a fair number of reheats to get the rough shape I want.

On another subject - A bladesmith I recently met says he uses WD 40 sprayed between the layers of steel he uses to make damascus. He says that the oil burns out the oxygen during the forging process and it reduces or eliminates the need for flux. This is the first I've heard of this technique and am curious as to how common it is?

[GHEzell]

1. Not really. Knock off the loose stuff and have at it.

2. I like to forge very close to finished shape, leaving the edge about the thickness of a nickle. To a point, it depends on the quality of your hammer-work, if you have a tendency to leave deep dings, you may want to leave more meat to the blade.

3. I just forged 2 blades tonight from 5160, and it took about an hour and a half working on one while the other was reheating. Yes, 5160 does resist the hammer more than, say, 1084, and takes a little longer. I worry more about temperature than time when forging, it is better to take more heats to achieve the shape you want than to forge too hot. Even then, a good set of normalizing cycles will fix most problems, as long as the steel does not go into sparkler mode... Decarborization is usually removed when the blade is ground to final shape, and can be avoided to some extent by controlling the forge atmosphere.

I have heard of oil being used in canister welds for that purpose, but not in regular patternwelding... interesting, it might work.