Working with Scrap Jackhammer BIts?

[Robert Simmons]

I am looking to use some jackhammer bits to make a hot cut hardie, Today I went down to the home depot tool rental place and asked if they had any jackhammer bits that were no longer serviceable and thus scrap. I scored 12 of them which amounts to a lot of tool steel. So now that I have them I am thinking of how to handle them metalurgically.

I think if I just heat them yellow and hit them with my hammer they will probably laugh at me. That may or may not be true. I know that when working spring steel, I have to upgrade to a 4lb hammer and smack the crap out of them. So I assume the jackhammer bits should be about the same.

So I am trying to think of a strategy to handle this. I had thought that perhaps if I anneal or normalize them three times perhaps I should have an easier time working them. Am I barking up the wrong tree here? Normalizing is easy enough and if that is sufficient then that is the route to go. If not then with annealing them i have more questions.

If I were to anneal them I would need to have some medium in which to anneal them nicely. Currently when I anneal I throw the part in my pile of brick forge, bring it to yellow, turn off the burner and button up the forge tight to help it cool slowly. However, I have heard that it is best to pack them in other materials that form around them. I had considered sand but I think the sand would melt around the steel at yellow temp so that may not be smart. What would be awesome would be small BB sized beads of refractory material you could pack the part in to cool but I know of nothing like that on the market. So any suggestions there?

If I am barking up the wrong tree or someone has a better suggestion, I am all ears and appreciation.

-- Thanks,
-- Robert

[Mills]

Robert have worked those bits aquired the same way you did. I also have some S-7 and don't believe they are the same thing. Others have pointed out that manufacturers use what is available that will satisfy the requirements cheapest. Junkyard rules are always in effect.

With that out of the way the most straightforward approach to this is sacrifice a chunk and see what happens. More importantly what you can do with it. There are some sophisticated ramping up procedures for certain alloys to get the best performance from them. i don't think you'd be able to duplicate that. You have what you have. Working any unknown steel and knowing that is is some type of medium carbon or an alloy steel I start at a lower temperature and see what I can do and how much force is needed. Then increase the temperatures as I become accustomed to its performance. and throw some away as I go. when finished forging I have vermiculite to put hot pieces in for annealing. If of a thin cross section I'll throw in a large piece with it to hold heat longer. Many times i won't bother with annealing and just normalize 2 or 3 times. set aside til it gets cool then reheat and let it cool again. After wards I have to decide what is most likely that I have, air oil or water quenching. take a good guess and try it.

That takes sometime and is part of the price you pay for the education. It is also why I don't scrounmgs as much as I used to. Takes a big bite of time to Make something if I only have enough for one. If there is enough that I can make several items then it becomes worthwhile to learn how to work it.

Happy hmmering

[arftist]

Forging at yellow heat, you are well above the critical temp for med-high carbon steel, as soft as it will get, anealed or not. If you need to do cold work such as filing, cutting, drilling, then anealing first is needed. The important thing with anealing is that the metal cools through the critical temps as slowly as possible. The method you are using is pretty good. If you want to further slow the cooling, put more metal in the forge. It can be mild steel.
For alternatives, wood ash is good.

Realize though, that tool steel will only get so soft, whether at yellow heat or anealed it is still very hard. If your anvil is large enough, enlist a striker.

My first hardy cut off was a jackhmmer blade already shaped like a cutter. I think I just ground the cutting edge a bit, and modified the shank to fit the hardy hole.

Let me take this opertunity to mention how I use a hardy cut off. After I cut most of the way through the work peice, I quench it. It the snaps off easily.
Using this method, I have NEVER struck my hardy with a hammer, nor struggled to make a cut.

[Mainely,Bob]

I would also vote for experimentation as you can never really be sure about a type of steel unless you buy graded metal from a known and reputable source.Those bits may have come from 2 or more sources who may use a different grade of steel for different types of bits so who knows how many different types of steel you have in that pile.
I would also keep detailed notes while I was doing these experiments.That notebook will pay BIG dividends later on by avoiding going down the same road twice(or more).

A four pound hammer will wear even an experienced younger smith out unless the arm swinging it does so on a regular basis and is used to the weight.The alternative is to stay with a lighter(2-3 pound)hammer but decrease the area of the point of impact.
This can be done by using half face blows on the edge of the anvil,slightly tilting the hammer so the edge acts like a fuller or just using either a ball or cross peen hammer to move the metal and then go back later with either a flatter or plannishing blows.
Knowing you are just starting out I am thinking you may be falling into the trap that some newer smiths do and that is using a bigger hammer and wearing yourself out when the better answer may be working smarter with lighter gear such as fullers or different "Dies" as B3 calls them.
Then again,there`s always the dreaded striker approach.
You never know,the wife/girlfriend/significant other may have a better eye than you and take to it like a duck to water. :)

[Robert Simmons]

Thanks for all the info. I am strong enough to wield the 4# with pretty much ease but I don't think much heavier would be feasible. I was thinking of having my 14 year old help with either the 4# or a 16# if need be. I do get concerned about the 16# impact on my small 70# farrier anvil. I would love a bigger anvil but I am afraid that will have to wait until finances permit. I would like to have an ozark pattern some day.

Anyway back to the bits, unfortunately i dont have a trip hammer (in fact I am not sure I could use that in my improvised workshop anyway as it might crack the garage floor with shock.) I wish I had a shop in the country somewhere and could afford a big blue. At any rate I think I need to master the hand hammer first before going for power tools.

Anyway it will be an adventure. Thanks for the advice.

-- Robert

[pkrankow]

Jackhammer bits are usually more similar to 1045 than S series due to material cost. Not saying S series jack hammer bits don't exist (they do).

1045 is pleasant to forge and moves easily at temperature. S7 is not as much fun.

I cut till about a 1/8 x 1/8 (maybe more) or so piece is left and twist it hot and the cut parts neat.

Cutting all the way hot is dangerous as you can have a very hot piece of steel land somewhere it shouldn't, like in some wood, under a wall, in some leaves, in a boot... Not to mention the potential damage to your tool and hammer.

Phil

[evfreek]

I tried one of these broken bits that a local smith gave to me. He told me that it was similar to an S series steel and had work properties. In my experience, it was not the same at all. I made identical tools out of this and an S-7 bar and let a couple of other smiths have at them. They ruined the tool made out of the bit. So I fixed it and it responded well to a water quench. It also sparked as a 50 point simple carbon steel.

Some smiths in a demo shop complained about the people rotating through the shop goofing their hardy. I made one for them out of known S-7 (bought from a reputable supply and spark tested). Years later, it is still fine. I found that it was hard to work by hand, but still faster than grinding.

There are spark photos in my gallery. They should be enough for you to figure out what your piece is.

[Timothy Miller]

My recent experience (last year) with jack hammer bits has been that they are 1045. I also went to the home depot rental center as you did and bought some used jack hammer bits for a $1 each. I spark tested them against a known sample and they checked out as 1045. In addition I checked with the manufacturer and they confirmed this. I think Vulcan made them. In the past jack hammer bits were made of better steel S-1 and the like but these days they use 1045. I personally don't really like to use 1045 for tools I think it is too soft for most things. I would use it for dies that I am only going to use for a short run or fullers, swages and such. If I were going to make a hardie from scrap steel It would probably be 5160 or perhaps 4140 but its a lot of forging work to make a hardie and why use less then the best steel for the job. It is going to be one of your primary tools. I made a hardie from S-5 a few years ago. It is nice and thin so it cuts easy and it has good red hardness. But that also makes it hard to forge so you will probably need a power hammer to do it. Just my two cents do what makes you happy. Also there is really no need to anneal 1045 just normalize it.

[Charles R. Stevens]

Drysweep/kittyliter fits the bill as a refractory material you can pack hot steal in to sneak it slowly.
A older welder that works with exotic materials turned menon to it.

[arftist]

Definitely don't use a striker or a big sledgehammer with a 70# anvil. The small anvil, especialy a farrier type is a big part of why it is so hard for you to move the metal.

[Alec.S]

first let me tell you My story!

last monday, i go to the local tool hire/ shop..... and i see that they have a hundred or so rusting jackhammer bits!
i go inside and ask the shop keeper weather they have any they would like to give me..... he says... those ones you saw out there are to be sent off into the city to be reforged..... the conversation continues and then he says... " i recall you saying you're a blackmith, would you be able to reforge them? i say yes and he gives me 3 to reforge.... just to see how i got on!
so that afternoon...... i put nice sharp tapers on three 1 1/2 inch jackhammer bits with a 2 2/4 pound strait pein hammer!
i was done in half an hour...... i definatly did wear me out.... ( who needs to go to the gym when you can go to the forge ! lol)
i got £8 for them..... not bad i say for 30 mins work!
so... yes you can... the steel i should suppose to be aroung the 1040 - 1050 mark...
it is tiring... but more than possible...
there is no need to normalize or anneal before forging....once above austenine ( i don't know how to spell it.), it makes no difference
more than possible
just have patience befor doing any final heat treats.... test out to see if it normalized is good if not harden and temper...

sorry for any spelling mistakes ( quick typing)


alec

[bigfootnampa]

Personally I find that I am most efficient with a 1.75 to 2.75 pound hammer when working heavy hard steel. With a 4 pounder my speed and fine control degrade too quickly. I would advise you to stick with a hammer size very close to what you normally use. Rather than changing hammers concentrate on the principles of concentrating force on small areas by using an appropriately fullered face/section of your hammer and delivering closely spaced overlapping blows. Even my nailmaking hammer at about 18 oz. has a small face and can be whipped through the air at high speed so that used for taking small bites it is quite effective even on hard and heavy steels. The only jack hammer bit that I have done much with was VERY hard stuff
(seemed like S7 to me) but it may have been pretty old. That was before I had my Anyang (which would have made a HUGE difference). You can see it here: Kurt's Chisel

[MattBower]

I had a slice of breaker hammer bit tested for chemistry. The guy who gave it to me (rents and services the hammers) assured me it was S5. Heard it from a sales rep. It tested at 1040-45 (within spec for both steels). I suspect the vast majority of them are in that range.

I don't think your problem is that the steel is terribly hard. (1040 isn't especially hard forging, and neither are the auto coil springs I've dealt with.) It's just that you're not very experienced at moving it around. You would think that smacking it hard, with a heavy hammer, would be all there is to it. You would be wrong. Get on YouTube and watch Mark Aspery and Brian Brazeal hand forge steel. I, for one, cannot make metal move nearly that fast, or with such precision. Very few smiths that I've seen can do so. It takes practice, and a certain amount of strategy. It's not all about brute force. Watch Mark's video on forging tapers, and notice how long the tip of the taper stays hot. Now you try it. :o

[Bob S]

I have to upgrade to a 4lb hammer and smack the crap out of them.

Robert,

I'm guessing that you're doing this (blacksmithing), more or less for 'fun'. If so, what's your hurry? If it takes a little more of less *forging* (not "smacking the crap out of it"),whats the hurry? The time spent forging, actually forging, is what it's all about.

Enjoy it.

Bob

this is a small cutoff hardy I made from a 'jackhammer point' a few years ago. The shaft is 1" square.

[Nakedanvil - Grant Sarver]

Having been a manufacturer of paving breaker steel for many years, over time, I had spectrographs done on every other manufacturers steel. To the best of my knowledge, the only time an "S" series steel has been used is for specific applications and usually that was only .680 chipper steel. These are a commodity product and the finished tool sells for less than the cost of "S" series steel.

For most of the last century 1078 was manufactured specifically for this purpose. Essentially a high silicone 1080. Brunner & Lay (the largest bit manufacturer in the world) uses a modified 1045. Vulcan used 1078 for most of a century and more recently switched to 15B40, a boron steel much like 4340. This steel will spectrograph as 1040/1045 because the boron is minute and often overlooked. I made millions of bits from 8630 and 8640 steel. Many chipper steels are made from 9260, an AISI grade very close to S-5 in chemistry.

Junkyard rules apply.

OBTW: "Jackhammer" bits have a hole down the center. Paving breakers sound exactly like a percussion drill (jackhammer), hence the modern misnaming.

[Nakedanvil - Grant Sarver]

Just a little trivia:

Way back when (even before my time) it was common to break rock by hand drilling a series of holes and driving wedge in the holes (actually "feathers" of half round with the wedge driven between them) to fracture the rock. Still done the same way only with power-driven or even hydraulic wedges or "powder" in the holes.

When it was done by hand a star drill was hammered to make the hole. It was called "jacking" and when done one-man it was called "single jacking". In a two man operation, one man guided and rotated the "steel" while the other swung a sledge and it was called "double-jacking". Even today some people still refer to a hand hammer as a "single-jack" and a sledge as a "double-jack".

As an aside to that, "John Henry was a steel driving man" means he was a driller and he was beaten by a steam drill or "Jackhammer".

[MattBower]

Great trivia, Grant. And great info about bits. But John Henry won! He just died in the process. (Or at least, that's the version I know.)

By the way, I just went back and looked at the data for the bit I had analyzed. I notice that it had 0.2% Si, which is consistent with 15B40. So who knows? It was a little low in manganese to be 15B40, though.

[Nakedanvil - Grant Sarver]

Great trivia, Grant. And great info about bits. But John Henry won! He just died in the process. (Or at least, that's the version I know.)

By the way, I just went back and looked at the data for the bit I had analyzed. I notice that it had 0.2% Si, which is consistent with 15B40. So who knows? It was a little low in manganese to be 15B40, though.

Yeah, that's the story ain't it? And the steam drill could only do maybe 600 blows per minute with a couple hundred pounds behind it. I've drilled a few holes in concrete by hand and a little electric hammer-drill can do about twenty to my one. Ya gotta wonder what 'ol John Henry was snortin'

15B40? Yeah, they do buy enough that they can tinker with the chem if they want. Been there - done that.

[bigfootnampa]

Gee Grant!!! I am most surprised that you still remember the specs on those old steam drills!! What a mind! JK

Thanks though, it is interesting to get more authoritative info. I guess the silicon is added to the alloys to improve impact resistance? Which would also tend to make it tougher on a guy trying to hand forge the stuff.

BTW I understand that even today some quarries are worked by driving wooden wedges into the holes and wetting so that the swelling of the wood breaks the slabs out. Apparently a centuries old technique.

[Robert Simmons]

OK so are you telling me it will make a crappy hot cut hardie? That is disappointing if true. I have been unable to find 5160 of sufficient size to make a 1" square for my hardie. I have been looking for coill springs off Semi trucks but have had no luck. I have no idea what I could salvage that would have a thick enough chunk of 5160 to make the hardie. I suppose the 1040 would be better than just mild steel ?

[MattBower]

OK so are you telling me it will make a crappy hot cut hardie? That is disappointing if true. I have been unable to find 5160 of sufficient size to make a 1" square for my hardie. I have been looking for coill springs off Semi trucks but have had no luck. I have no idea what I could salvage that would have a thick enough chunk of 5160 to make the hardie. I suppose the 1040 would be better than just mild steel ?

First, no, it'll work fine. It just may require more frequent resharpening than something like S7. It'll also work considerably easier.

5160 leaf springs are easy to come by, and someone already mentioned the possibility of a leaf spring hot cut that sits on the diagonal. Here's a picture: http://www.britishblades.com/forums/showthread.php?71002-Sashimi-knife-how-to&p=1030266&viewfull=1#post1030266

[Nakedanvil - Grant Sarver]

Don't underrate 1045. It will get as hard as you need or want for a hot cut hardy and will stand up extremely well. Paving breaker chisels take an incredible pounding. Most people are thrilled with a hardy made from a paving breaker bit or an old axle. The trade off between the difficult working of real "S" steel and (maybe) a shorter life for 1045 is a no brainer when working by hand. Besides, you can use the collar to save a lot of the work.

Plain carbon steels are the most wrongly underrated product in metal working. They served blacksmiths very well for a couple thousand years

Besides, no one said 1040. 1045 modified for impact or 15B40 which has nearly 1% chrome and enough boron to make it very hardenable.

Even today medium carbon and low alloy steels are very popular in forging shops for all kinds of tooling. Better steels are harder to deal with and are only used for very long run production. I've cut hundreds of pieces of steel with a 4140 cutter without dressing it at all.

[Robert Simmons]

Thanks for the clarification. I am happy to see I didn't totally waste my time. of course I now have to get it shaped and ground before it can be sharpened. I have a 1" hardie hole and the bit is hexagonal with 1" width at the flats and 1 1/4" width across the points. I was thinking of whether I will have enough metal after I flatten two of the corners. I hope I will have enough. I suppose I could do an upset to push in more material but I was thinking that if I didn't have enough to make it fit absolutely tight, It wouldn't be bad if it was asymmetric octagonal where the corners are cut by a small amount of space. It would probably still sit well in the hardie, what do you think? I absolutely intended to make use of the collar.

Any preference to double bevel versus single bevel hardies? What about curved hardie edge versus flat?

Thanks in advance.

Oh, by the way, as for spring steel, I have a couple of coils of that but its maybe 1/2" diameter rod when flattened so I don't know how I could use that to make a tight fitting square hardie. I have been looking for sources of 1" or bigger rod spring steel for scrap but have had little luck.

[Nakedanvil - Grant Sarver]

Don't worry too much about the fit. I think a hot cut should fit a little loose, not floppy, just not snug, so that it can be inserted and removed quickly and easily. A bick I prefer to fit snugly, depends on the usage. I don't think I'd have any problem with a hot cut having a round shank. Think about it. You could turn it any way you need and once you nick into the bar at all there's no way it could turn. Definitely make it curved like an axe. Brian Brazeal fans his out into a near half-circle.

Have fun and don't worry so much. Today just make tools that work. Tomorrow make great tools. Your idea of what is needed will change over time too.

[fciron]

I have a 1" hardie hole and the bit is hexagonal with 1" width at the flats and 1 1/4" width across the points. I was thinking of whether I will have enough metal after I flatten two of the corners.

I hope you mean that you will flatten two corners that are opposite each other, not two sets of corners.

I make 1" hardy tools out of jack-hammer bits and they fit fine. Even if they didn't fit the hole completely it is not really necessary that they corners be filled. Flat contact on all four sides and the collar on the face of the anvil will be plenty of support.

Grant, what is 'balling a jack'?

It's mentioned in a few folk songs, I thought it might just be running a jackhammer, but if you can clarify that would be cool.