Cracked Collins Legitimus: What Do You Do?

My uncle was a welder for 50 years. On many occasions, i would watch him fix cracks in steel, aluminum, cast steel. He always fixed them the same. He ground down into the crack, on each side if it was a thick piece, until he was right through it. Then widen it up a little bit. Then, with the appropriate welding rod/wire & welding machine (Tig/Mig/Stick/etc...), he would make passes & fill it in. He told me over & over that the repaired spot would be stronger than the rest of it. He also said none, not one, of his repairs came back because the weld broke. He once welded up a huge cast spoke weighted wheel from a tractor that was part of the old belt driven power equipment sawmill stuff. It was shattered & in about 15 pieces. We worked on it all weekend but he got it fixed. He used a ratchet strap to hold it all together. I have seen him do tools & axes as well. He did say axes should be re heat treated & tempered though. Too bad he is retired from welding now.
 
Interesting advice so far.

If I weld it, I will let it cool without pounding on it. I will then grind everything flush, including thickening up the edge just a tiny bit, and then normalize 3 times, likely at descending heats of about 1600F, then 1550, then 1500. I will also soak at these temperatures a bit longer than usual in hopes that carbon diffusion will largely draw carbon from the high/medium carbon original axe head into the low carbon weld thereby equalizing the carbon content throughout. (BTW, does anyone have any information on what steel Collins used for the Legitimus line?)

For rehardening I will soak again, a bit lower at 1475 or so for about 5 minutes, then quench into Parks 50. I am considering just fully hardening the entire head, rather than just edge quenching the bit. At the thicknesses of this piece, neither the entire edge nor poll will fully harden, but they will be a lot stronger than just steel that has been heated and cooled. And, when tempered around 500-550F everything will be plenty tough. (I'll begin the tempering at 500 and decide how far to go based on how the edge works with a file.)
 
There are hard face welding rods that might make the repair and not require hardening and tempering.
 
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To flatten the weld so that you dont have to grind that much. Moreover, if the welding process goes somehow wrong, punding will show any imperfections.
 
John Frankl said:
Interesting advice so far.

If I weld it, I will let it cool without pounding on it. I will then grind everything flush, including thickening up the edge just a tiny bit, and then normalize 3 times, likely at descending heats of about 1600F, then 1550, then 1500. I will also soak at these temperatures a bit longer than usual in hopes that carbon diffusion will largely draw carbon from the high/medium carbon original axe head into the low carbon weld thereby equalizing the carbon content throughout. (BTW, does anyone have any information on what steel Collins used for the Legitimus line?)

For rehardening I will soak again, a bit lower at 1475 or so for about 5 minutes, then quench into Parks 50. I am considering just fully hardening the entire head, rather than just edge quenching the bit. At the thicknesses of this piece, neither the entire edge nor poll will fully harden, but they will be a lot stronger than just steel that has been heated and cooled. And, when tempered around 500-550F everything will be plenty tough. (I'll begin the tempering at 500 and decide how far to go based on how the edge works with a file.)
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I know just enough about welding to get myself in real trouble sometimes, but I think I remember a friend of mine who is an old welding instructor mentioning one time that high carbon steel is a bitc@ to weld without cracking when it cools. I think that is why the oldtimers peened the weld as it cools. It is supposed to reduce the stress in the steel left over from the welding process.

I don't know what the carbon content of this head is or whether it is high enough to require special processing to survive the welding process.

Hope I've helped muddy the water sufficiently!

Regards,

Jeff
 
if you're using a stick welder, you could use 1065 rod and "probably" be close enough on your steel match.
I used to know a guy who welded cast iron with 1013 rod starting by heating the entire cast piece to 600F before welding to limit thermal shock to the surrounding metal.

your plan of action looks pretty good to me, with the 3 normalizing cycles and tempering to 500.
 
"There are hard face welding rods that might make the repair and not require hardening and tempering."

The problem would be the heat affected zone around the weld. Regardless of the hardness of rod, other parts of the edge would likely get hot enough to be softer than I would like.
 
Yeah but you can minimize the area of heat by clamping wet rags to the blade on either side of the weld. A skilled blacksmith whom I respect suggested just welding it - no heat treat.

I bet you could get the rags as close as a 1/2 inch apart. 1/4 inch of that area will be the weld. And probably 1/16 adjacent to the rag wouldn't reach tempering heat. So you end up with 2, 1/16" wide softer areas on either side of the weld. That's probably not worth going though through the hardening and tempering processes unless you just wanted to do it for fun.
 
Go for it! :>

Considering the narrower wedge of the axe it wold stick deeper into the wood.
 
Thanks, Square peg. Certainly worth thinking about. I'd likely redo the whole thing 75% for fun and 25% because the original crack makes me suspect the original heat reatment.

Pindvin, the crack is right at the edge, so no reason to grind away the top and bottom.
 
If you're set up to do the heat treat then you may as well go for it. If nothing else it's a grand experience.
 
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"One test result is worth one thousand expert opinions."

Wernher von Braun - The man who led NASA to space
 
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