Ferguson Posted February 14, 2011 Share Posted February 14, 2011 I am now 0 for 6 on hammers. Every hammer that I have made has cracked, some in more than one place. What causes cracking? Working material too cold? What color should the hammer be before I start to hammer on it? ===============================Home Made Hammers General note: The hammers are shown in reverse chronological order, so the newest hammers are at the top. I did not keep track of the number of heats. Suffice to say that it was many, partly because my forge will not get hot enough. My propane forge will not get hotter than orange, even after adding a second burner, and tuning the burners on the bench. So I am working with the forge that I have.Hammers 4, 5 and 6 Process for Hammer 4: I started with 8 inches of 1045 steel, 1/2 inch square. I used a oxy-acetylene torch to heat the end of the bar, and then beat it on a steel plate on the floor to upset it. I drilled two 1/8 inch holes, 3/4 inch apart, to facilitate slitting for the hammer hole. Then I used a hot chisel to make the slit between the two holes. Then I used a series of drifts to drift the hole bigger. I tried to be patient, leaving the hammer in the fire longer than last time, to get it as hot as possible, and only hitting the drift a couple of times before putting it back in the fire. I drifted it to 3/4 inch by 1/2 inch oval for the hammer handle. Then I cut the hammer from the bar. Results for Hammer 4: Inspection revealed a long crack, marked with an arrow, so I put it aside. Process for Hammer 5: I started with 6 inches of 1045 steel, 3/4 inch square. I used a oxy-acetylene torch to heat the end of the bar, and then beat it on a steel plate on the floor to upset it. I drilled two 1/8 inch holes, 3/4 inch apart, to facilitate slitting for the hammer hole. Then I used a hot chisel to make the slit between the two holes. Then I used a series of drifts to drift the hole bigger. I tried to be patient, leaving the hammer in the fire longer, to get it as hot as possible, and only hitting the drift a couple of times before putting it back in the fire. I drifted it to 7/8 inch by 5/8 inch oval for the hammer handle. Then I cut the hammer from the bar. Results for Hammer 5: Inspection revealed a long crack, marked with an arrow, as well as another crack around the hammer hole, so I put it aside. Process for Hammer 6: I started with 6 inches of 1045 steel, 3/4 inch square. I used a oxy-acetylene torch to heat the end of the bar, and then beat it on a steel plate on the floor to upset it. I drilled two 1/8 inch holes, 3/4 inch apart, to facilitate slitting for the hammer hole. Then I used a hot chisel to make the slit between the two holes. Then I used a drift to drift the hole bigger. I tried to be patient, leaving the hammer in the fire longer, to get it as hot as possible, and only hitting the drift a couple of times before putting it back in the fire. I stopped after the first drift to inspect the results. Then I cut the hammer from the bar. Results for Hammer 6: Inspection revealed a small crack, marked with an arrow, so I put it aside.Hammer #3 Process: I started with 6 inches of 1045 steel, 3/4 inch square, 0.9 pounds. I used a oxy-acetylene torch to heat the end of the bar, and then beat it on a steel plate on the floor to upset it. I drilled two 3/16 inch holes, 3/4 inch apart, to facilitate slitting for the hammer hole. Then I used a hot chisel to make the slit between the two holes. Then I used a series of drifts to drift the hole bigger. I tried to be patient, leaving the hammer in the fire longer than last time, to get it as hot as possible, and only hitting the drift a couple of times before putting it back in the fire. I drifted it to 7/8 inch by 3/4 inch oval for the hammer handle. Then I cut the hammer from the bar. I put the hammer in a vise, heated the end I had just cut with an oxy-acetylene torch, and hammered it to upset it. I rounded one end, as I intended to have one square end and one round end. Results: No cracks around the drifted hole, but cracks on both ends, apparently from the upsetting process. Note that the upsetting did not seem to cause cracks in hammer #2. Patience seems to have paid off in the drifting process on hammer #3, so I need to be similarly patient with the upsetting process, taking the time to get the ends very hot. I will try again. I purchased some 1/2 inch square 1045 steel, I may try that for my next hammer, make a lighter hammer. Smaller stock will heat up and cool down faster. I may also make some additional oval drifts in smaller sizes, perhaps 3/4 by 1/2 inch.Hammer #2 Process: I started with 8 inches of 1045 steel, 3/4 inch square, 1.2 pounds. I used a oxy-acetylene torch to heat the end of the bar, and then beat it on a steel plate on the floor to upset it. I drilled two 3/16 inch holes, 1 inch apart, to facilitate slitting for the hammer hole. Then I used a hot chisel to make the slit between the two holes. Then I used a series of drifts to drift the hole bigger. I drifted it to 7/8 inch by 3/4 inch oval for the hammer handle. However, the hole was larger than the drift, so I drifted it to 1 inch by 7/8 inch oval. Then I cut the hammer from the bar. I put the hammer in a vise, heated the end I had just cut with an oxy-acetylene torch, and hammered it to upset it. I rounded one end, as I intended to have one square end and one round end. Results: The upsetting went well, increasing the end from 3/4 inch to 15/16 inch, in three heats. The two 3/16 inch holes were apparently too far apart, so the hammer hole ended up bigger than I had intended. Unfortunately, there were cracks on both sides of the drifted area, perhaps resulting from letting the metal get cold during the drifting process. Overall, I think that I am getting closer to a process I can live with Next: Try again with 6 inches of 3/4 square, aim for a lighter hammer. Drill holes 3/4 inch apart. When drifting, limit the drift to three hits and then drive it out. Hammer #1 Process: I started with 8 inches of 1045 steel, 3/4 inch square, 1.2 pounds. I drilled two 3/16 inch holes, 3/4 inch apart, to facilitate slitting for the hammer hole. Then I worked on necking down the two ends, making the hammer longer. Then I used a hot chisel to make the slit between the two holes. Then I used a series of drifts to drift the hole bigger. I ultimately drifted it to 7/8 inch by 3/4 inch oval for the hammer handle. Results: Not good. Tapering the ends, using my toy power hammer, took a long time, and the result looked very rough. After I had finished, I heated part of the hammer, near the head, in order to straighten it. The long crack you see on the left was the result of a couple of light blows to straighten the head. Next: Try again, but do not taper the ends, just upset the ends to make the hammer head larger. I don't see a way to go forward at this point, kind of like I have run out of ideas. I may try to go visit a local expert blacksmith, and see how he makes a hammer. My home made forge may be part of the problem. I have spent a fair amount of money and effort trying to improve the forge, lining it with ITC-100, adding a second burner, trying different MIG tips, tuning the burners, without the forge getting any hotter. I don't have the cash at the moment to buy a commercial forge. Details from the link My home made hammers --------------------------------------------------------Forge burnersBurner Experiments When I added a second burner to my forge, I copied the dimensions of the first burner, but did not have the results that I wanted. The second burner did not work nearly as well as the first burner, either in the forge, or on the bench. These are both Reil type 3/4 inch pipe burners, using .023 inch tapered MIG tips. Note that I live at 5000 feet, so I need to use a smaller tip due to lower air density, to get the right fuel-air mixture. Previous experiments with the first burner persuaded me that the 0.023 inch tip was correct, the others ran too rich. After considerable head scratching, I decided to put both burners on the bench, and swap parts until I understood what was happening. After swapping parts, and more head scratching, I realized that both the burner flare and the jet tube mattered. Then I put the first burner back together, and checked how it was running, which was well. The second burner was still not doing well. I tried different stickout of the flare, and found that fairly critical. If I slid the flare back to where it was flush with the end of the pipe, which really meant no flare, I could not light it. If I moved the flare to where it was sticking 1.8 inches past the end of the pipe, that did not work well either. The correct number turned out to be around 1 inch. Note that the flare on the first burner, purchased a few years before, worked OK at 1.8 inches. Looking at the flares, I could see that the newer flare was a little different, a bit longer. How far the tip went into the bell adaptor also seemed to matter. If I stuck the tip too far into the bell adaptor, the flame would blow out at higher pressures. Finally I realized that if I pulled the tip out further, it would run correctly. The big surprise to me is how differently the two burners tuned up. Dimensions that worked on one burner did not work on the other burner. But I finally got both burners to work correctly. The photos below are of the second burner that was originally working poorly, after I finally got it tuned right. Burner at 2 psi Burner at 15 psi The first burner seemed to work better with a flare stickout of 1.4 inches than 1.8 inches, so that is where I left it. Note that in the beginning, the first burner tip stuck almost one inch deeper into the bell adaptor than the second burner. I later pulled out the tip, similar to the second burner. So don't just blindly copy dimensions, realize that you need to experiment to get the adjustments right. So the burners worked pretty well inside the forge, they both have a nice cone of flame, similar to what you see above in the photos. However, the forge does not seem to get much hotter than it was with one burner. I was hoping to get to white heat, but at orange-yellow. ----------------------------------- All Very frustrating, of course. Richard Quote Link to comment Share on other sites More sharing options...
Glenn Posted February 14, 2011 Share Posted February 14, 2011 Please read the article on Seeing Colors. Tell us what you are doing now. What steel are you using? How much soak time in the forge, what color do you start working the metal, what color do you stop and go back to the forge to reheat? How many heats? Etc, etc Once finished what process to you use to heat treat the hammer? Etc.etc. We can guess all day long as to "what if," but we need to know what you are doing before we can make suggestions. ------------- You say you have a homemade 5 gallon bucket forge, which I made a few years ago. but I knew that there was room for improvement. I calculated the volume as 263 cubic inches. The outside and inside of the forge taper, with the front a semicircle 7.5 inches wide by 4 inches tall. The rear is 6.5 inches wide by 3 inches tall. The forge is 13.5 inches long. From the photo of your forge it would appear that both ends are open. My first suggestion would be to close one end to the forge builds up and retains heat. I pulled the information from your link so we could better assist you in answering your questions. Quote Link to comment Share on other sites More sharing options...
Ferguson Posted February 14, 2011 Author Share Posted February 14, 2011 The steel that I am trying to make hammers out of is 1045. I don't seem to be able to get my work beyond medium to high orange in color. I put it back in after three or four hammer hits, generally. I have some scrap steel that I leave in the forge to keep whatever I am working on off the bottom, and it gets to medium yellow, eventually. How long should I expect it to take for 3/4 inch square steel to come to temperature? I leave it in the forge for a minute or two, no more. In the middle of this process I upgraded my heating torch, from a Victor #2 oxy-acetylene cutting tip, to a Victor size 8 oxy-propane rosebud. The rosebud does not seem that much hotter than the cutting tip. I usually do close the back end of the forge, not sure that makes any difference. I have yet to try to heat treat any hammer, as I find cracks in every hammer before I get to that point. What else do you need to know? Maybe I should make a video showing my process...... I watched a video of Mark Aspery making a hammer, and was amazed at how long he left the piece out of the fire, at least triple the amount of time that I would leave it out. Richard Quote Link to comment Share on other sites More sharing options...
rthibeau Posted February 14, 2011 Share Posted February 14, 2011 you should leave the steel inside the forge at least 5 minutes to start with...after the forge has heated up...don't take it out until it gets the temperature color you want to play with. If it takes longer than 15 minutes to get 3/4" sq bar hot enough, then the forge is underheating. Oh, and I use 1.5" sq 1045 to make hammers. Never had one crack like yours. Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted February 14, 2011 Share Posted February 14, 2011 Looks to me like a seam in the bar of steel you made them from. Quote Link to comment Share on other sites More sharing options...
rthibeau Posted February 14, 2011 Share Posted February 14, 2011 Figures the Grant would come up with something seamy...... :huh: Quote Link to comment Share on other sites More sharing options...
Ferguson Posted February 15, 2011 Author Share Posted February 15, 2011 Looks to me like a seam in the bar of steel you made them from. I have cracks coming from two different bars of steel, 1/2 inch square and 3/4 inch square, so I don't think that it could be the steel. Richard Quote Link to comment Share on other sites More sharing options...
ciladog Posted February 15, 2011 Share Posted February 15, 2011 I have to agree with Grant. I have bought square bar many times and found a fold seam from the mill rolling running the entire length. Sometimes you can't see them until you start to forge the steel. I bring them back to the supplier for exchange even if I have cut them up and they take them back. Quote Link to comment Share on other sites More sharing options...
forgemaster Posted February 15, 2011 Share Posted February 15, 2011 I'm with Grant on this too, 1st thing I said to my self was "seam in the bar". Get a piece of bar stock that is from the same bar lenght (heat No. etc) and either die penetrant test it, get it tested, or mag particled, at the least try, oil soak the sample, clean it well, then dust with chalk and leave it for a few hours. The chalk will draw the oil out of the seam/flaw if there is one. Even though you are using 2 different sizes and finding the same problem with both, does not mean that those 2 sizes were'nt rolled out of the same billet. Phil Quote Link to comment Share on other sites More sharing options...
Ferguson Posted February 15, 2011 Author Share Posted February 15, 2011 OK, I decided to test the "bad bar" hypothesis, so I started with a 3/4 inch square 4130 bar. I was very careful not to quench it in water, I just let it air cool down to 300F. No cracks were found, hallelujah! That does not prove that the 1045 bars were defective, as I was careful never to water quench it, and 4130 is a very different alloy than 1045. But it is certainly possible that I was working with bad 1045 bars. I don't have access to a dye penetrant system. So how should I heat treat it? I don't have an oil bath, don't even know what oil I should use if I wanted to set one up. Since my work is pretty small, hammer heads, punches, etc., I should be able to use a quart paint can or something like that. Should I use a gallon can in an attempt to reduce splatter? Would it be OK to quench it in water? Which cools the metal faster, oil or water? Obviously the hammer is pretty rough, but I am interested in function not appearance. If I can get a working process I can then work to improve the appearance on the next hammer. As an aside, I made a very crude set of tongs to grab the hammers, using 1/4 by 3/4 bar, and they seem to work. No way that the hammer will be able to slip out of those tongs, as I welded pins onto the jaws to engage the hammer hole. Richard Quote Link to comment Share on other sites More sharing options...
rthibeau Posted February 16, 2011 Share Posted February 16, 2011 4130 should be quenched in oil. A bucket of used motor oil could be used...outside....but peanut oil is a good inside choice, about 2 gallons in a container for what you are making should suffice. I have used bars of steel with this apparent seam on one side without any cracking or other problem......not to say that wasn't your problem, just that I haven't seen that result. Still might be that you weren't letting it get hot enough before hammering. Keep at it and things will get better. Quote Link to comment Share on other sites More sharing options...
evfreek Posted February 16, 2011 Share Posted February 16, 2011 Hi Ferguson. It looks like you might have this problem solved. That is good news. One thing that made me nervous about your process is using an oxy-acetylene torch to heat the 1045 bar for upsetting. I would be very careful about upsetting anything other than mild steel unless the heat was pretty even. Somebody at a demo told me this, and it made sense, since the outer fibers of the metal are suffering extension that may violate forging rules. Start big and draw down. Trying a different bar of different steel is also a good idea. I have seen beginners mess up similar leafing hammers made out of A36. Maybe going with mild steel might be a good idea if you are just starting. Many don't heed this suggestion, including me. The blacksmith who helped me make my first hammer (out of 1045) made his first mild steel hammer years later. He told me that someone suggested it has a "stickier" sweet spot and was much less likely to send a punch skittering across the room with an off center blow. After he tried it out, he proclaimed that it, indeed, worked exactly as advertised. Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted February 16, 2011 Share Posted February 16, 2011 I used to seam test bars for E.M. Jorgenson. Take a piece of bar 2 - 3 times the bar size in length. So 3/4" X 3 = 2-1/4. So take a piece two inches long, heat it up and upset it down to one inch long. If there are any seams they will open up. 'Course I was doing pieces up to 10" or so diameter. Also note that square bar is more likely to have a seam than round bar. Also, you are getting "merchant quality" bar not "forging quality" bar. Quote Link to comment Share on other sites More sharing options...
Iron Clad Posted February 17, 2011 Share Posted February 17, 2011 I would not use cold water to quench that 4130. Oil at room temp. or even luke warm oil is best. Also, try closing both ends of your forge when heating especially on the first heat. I built a gas forge from a large piece of square tubing that is approx. 25" long and only one burner, after closing both ends it heats in no time. Working the 1045 too cold may have been the problem. Don't hammer on carbon steel when blood red, too cold. I usually stop hammering when orange. Quote Link to comment Share on other sites More sharing options...
Old N Rusty Posted February 17, 2011 Share Posted February 17, 2011 sorry if this is not the place for this DUMB question .wife is a vet garage sale buyer of ALL tools she thinks i might like. BLESS HER. she foune an old rail road spike hammer head.. not planning to be a John Henry any time soon i look at with eyes of a smith what can i make out of this? i band saw the thing till i got a handled hunk and two nice pieces. the bit with the handle hole is saying" make me into a raised vein leaf veiner " so i took cutoff wheel grinder, and cut a leaf vein lookalike in it cross handle oriented. now dumb stuff is it "safe"to bash it as is ? seems to me it is tough stuff and i cold cut it with saw so whatever temper was there i did not change by heat . iknow absolutely naught about making tools i just buy hammers abuse them unmercifully and take the remnants to tailgate sales.( amazing what some folks will buy!) if too dumb to answer sobeit pax Quote Link to comment Share on other sites More sharing options...
gearhartironwerks Posted February 18, 2011 Share Posted February 18, 2011 4130 should be quenched in oil. A bucket of used motor oil could be used...outside....but peanut oil is a good inside choice, about 2 gallons in a container for what you are making should suffice. I have used bars of steel with this apparent seam on one side without any cracking or other problem......not to say that wasn't your problem, just that I haven't seen that result. Still might be that you weren't letting it get hot enough before hammering. Keep at it and things will get better. The specs for this steel suggest an oil quench, as with 4140 and 1045. However, I've found that an oil quench did not get hammer heads hard enough and have successfully used water as a quench. I think the key is to normalize, then anneal following forging. Then, immediately after hardening in water, temper for 2 hrs at 400 degrees. I have a heat treating kiln and heat the pieces to 1550 deg prior to quenching in water. Used kilns are inexpensive and readily available. If you're serious about metallurgy/tool making, it's a good investment. Heat treating info for most of the materials we use is readily available on the net. I keep a heat treating notebook of formulas, and of failures and successes...mainly because I can't remember anything. John Quote Link to comment Share on other sites More sharing options...
Ferguson Posted February 20, 2011 Author Share Posted February 20, 2011 I made another hammer, number 8, using 3/4 inch square 1045 alloy, from the same bar that was cracking on me previously. I kept it away from the water, and let it air cool. I did not get any cracks, even after I quenched it in oil. My conclusion was that repeatedly cooling the bar in water caused the cracking on hammers 1 through 6. That does not say that there were no hidden defects in these bars, but it does indicate that by eliminating water cooling from the process I minimize cracking. I am not too worried about making these hammers as hard as possible, since I plan to use them on sheet metal. I still need to temper them; I plan to put them in an oven at 300F for an hour or two. Thanks to all for your comments and encouragement. Richard Quote Link to comment Share on other sites More sharing options...
MattBower Posted February 21, 2011 Share Posted February 21, 2011 Just FYI, most oils are too slow as quenchants to produce much hardness in 1045. Quote Link to comment Share on other sites More sharing options...
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