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I Forge Iron

Jack Hammer Hardy's


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A while back I bought some Jack Hammer Bits at a flea market. Brought them home and stuck them under a bench till I had time to forge for me. I made some time yesterday and this morning. So I made 3 hardys. A cold cut, A hot cut and a snub scroll hardy. Here are the finished tools.

John

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Very well done! I havent made hardys yet- I think the hardys ill make will be more inclined to the smithing magician type- a frame with a lot of attachments that fit in a sliding frame- you really did a nice job on those!
Bb

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Thanks for the feed back guys.

David S.
Forged at a good bright orange, Normalized by letting them air cool overnight and then heated them to non-magnetic Then Quenched the working end in oil, Hit the tip quickly with the belt grinder and then let it draw heat from the shank end to a purple color. Then quenched the whole hardy in oil till cool.
Got the tempering out of one of the Best of the Bits from the AFC.
Will get to try them out on Thursday.

John

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Those are nice! I made a few straight hardies in the past from jackhammer bits. If you go to a place that rents jackhammers they will sometimes have broken ones ~ that's how I got mine (free!). I think that they are made out of S2 or S5 steel, if that helps anyone with the heat treat.

Steve

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Nice. I have a few around that I mean to make into tools. The collar obviously makes a good hardie tool. The shafts will probably be hammers, and the working ends will either be stakes or hammers depending on the shape. At least one will probably be a creasing stake.

Do the S-steels tend to have any markings? The NTBA Junkyard steels chart claims S5 as typical of jackhammer bits.

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Jacob,
I can't answer you questions sorry. I have a relatively low tech approach. Grinder shows High carbon, smack the end with a flea market ball pien. creases the hammer face not the edge of the bit. Forge, temper and smack tool edge again with flea market ball pien. Still creases hammer face not tool edge.
Not scientific,not safe and not an approved method but an honest answer anyway.

John

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You ever get a hunk of microalloyed strain hardened leaf spring and try to harden that like it was 5160 you will remember that such charts are "suggestions" and even then they can be coloured by the local pool of scrap of the people creating them. (personal experience)

Sometimes they are also back evolved---ie Machinerys Handbook says that Sx is a good steel for jackhammer bits gets turned around into jackhammer bits are Sx even if no place makes Sx bits cause they cost too much...

Why I weasel word anthing I make out of scrap steel that I can't *prove* is an exact alloy. If I don't know; I don't claim that it is.

A friend of mine is going to be brining me some 100 year old mining steel, (drill bits, machine parts etc) off his ranch which was the largest Mn mine in the world at one time a long time ago; guess I will have fun trying to figure out what it might be; but hope it's just plain carbon steels.

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Hi JWB. These are really nice hardy tools. I wouldn't worry about what kind of steel they are as long as they perform well. If you make a hardy out of mild steel, you will find out right away. Tom Clark makes his out of truck leaf spring. Not simple 10xx carbon steel. They work just fine and sell too. They are just beautiful. I have an old hardy, looks like more than 50 years old, and works well even though students abuse it. My striking partner made one out of mystery steel and he needs to sharpen it every two or three cuts. Mark Aspery prefers hot cut chisels, and he gave an excellent rationale during his demo at the last California Blacksmiths Association spring conference. One of the workshops was to make one out of "blacksmith qualified as 4130" sucker rod. The one I made was ruined in an instant when a beginner saw it, borrowed it without asking, and tried to plow it through a barely hot 1" bar. I fixed it, and it has worked really well as long as it is not abused. It works almost well enough so that I do not miss the hardy.

I don't know how to spark test S-2. Besides, I don't think it is used much for jack hammer bits. Might be able to find some in oilfield scrap. S-5 has enough molybdenum so that you can see it in the spark (0.45%). You can check my spark photos in the gallery for references. :cool:

Probably a better way to figure it out if you are really interested is to do a heat treat test. Most of the S series of steels will still be pretty hard if tempered to 800F to 1000F. S-5 will be 52-55 Rc. S-7 maybe higher and S-2 maybe 40 some odd. Simple carbon steel will not be this hard if tempered to 1000F. Put a piece in a muffle furnace and get it up to a light glow in the dark. A file may scratch but it will not cut well. Remember that the S series have secondary carbides, so you will have to heat to a higher temperature before quenching. S-7 will be very hard if allowed to air cool, and a file will not cut at all.

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evfreek,
My view on it is since they are made out of used jack hammer bits it's probably already seen more abuse than I can dish out (although my dad always said I could tear up an anvil in a sand pile with a feather). I don't get to wrapped up in numbers and letters.;)
Thanks for the info though.

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I don't know for sure what the jackhammer bits I used were made of. I do know that they were definitely more redhard than 10XX. S1 or S5 was simply a guess based on charts I had seen. Regardless, brought them to critical as judged with a magnet and oil quenched. Drew the temper on the edge to a brown and called it good. Might not have been optimal but was free and worked well for me:D

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