evfreek

How about going Chinese? In other words, forge like the Chinese did. The main problem about these cast iron anvils is that their edges degrade rapidly, since they are high stress areas. On a Chinese style anvil, the edges are heavily radiused. The shape is almost like a loaf of bread. Not having a decent edge on your anvil is going to be limiting for two main techniques: isolating and drawing. Both can be done with the appropriate (steel) hardy tool which is designed to spread the stress over more of the comparatively weaker anvil face. Cast iron is weaker in tension. A hardy tool stresses the body of the anvil much more in compression as opposed to the edge techniques typically done on a western style anvil. Someone from China once posted a picture of his setup on the web. What was remarkable was the heavily rounded shape of the top of the anvil and the tremendous assortment of hardy tools he had. Nobody sneered or poo-poohed his setup. But it requires different techniques.

My path to success has not been smooth. The worst thing that I have tried is TPAAAT. It has never helped me acquire any anvils. But, there is one thing that I have learned. TPAAAT, like many other things, tends to leave the control out of your hands. If you really want an anvil. don't wait for someone to tell you about his uncle's friend's brother-in-law, unless you really like following these tenuous trails. My first anvil was a concrete brick. It lasted long enough to forge two tools, but that was good enough. The second anvil was a piece of railroad track. The best thing that I did in my quest for an anvil was to spend $100 on a Miller Thunderbolt stick welder. In the time that I could have allowed TPAAAT to hold back my learning progression, this simple welder can easily turn out a dozen anvils. Seize the opportunity. The best time to begin is now!

I never did find any of that odd flint that I saw at Four Corners. Maybe later, when I go there again. I eventually found some better web resources, especially a Youtube video about finding flint (chert) where it does not naturally occur. Look at rock fill, especially near railroads. Most of the fill rock was local. There was a lot of basalt, and nothing like the one in the video with 50% flint! Eventually, I found one piece in a landscape job that looked just like the example. This worked great. Another video recommended jasper. But this does not have the correct fracture geometry, and requires a lot of work with the hammer to get a good edge. It does, however, work as well. The drill bit mystery was not quite solved. Thomas pointed out that the drill bit could be HSS which doesn't throw the same kind of sparks as simple carbon steel. Not for the bit I was using. The tip blew out while drilling aggressively, and it turned out to be an old carbon steel drill. It is really easy to see the difference between 1080 and HSS with a spark test, but the bit could have been 1085. It is not HSS, for sure. Anyway, it worked, but with much difficulty, with the correct rock. Probably, it was not full hard, and the spiral flutes make it difficult. I will try unwinding it and hardening it better. Anyway, thanks for the help. Flint and steel is fun. Eventually, I'll get back to the Arizona question. Meanwhile, the main points are: get a smooth full hard piece of steel, and although the type of fine grained quartz sedimentary rock may not matter much, the fracturing pattern of flint really helps to get that nice edge. Rounded rocks do not work well. Videos help to show the striking technique.

Hi. Thanks for the information. I was trying to use the tip of the file. Now I know that I have to use the edge of the file with the teeth ground off. I used to have a geology pick, but lost it quite a while ago when I decided that I was not going to study geology. I will try the striking off a hammer head as well. I tried using a large carbon steel drill bit (no teeth), but this may have been the wrong kind of rock. Doing a web search on the Indian rock drawings and Arizona flint did not turn up much. The only hit I got was for Payson, Arizona, which is quite a distance from Four Corners. That site had a large picture of whitish rock with red streaks, which looked a lot like the rocks I saw. I will try watching that video that was suggested for finding flint in California. I think that I may have already seen it and it did not help much. I have some strong, hard rocks, but these do not throw any sparks. I also have obsidian, but as mentioned earlier, this does not work. I also have illumite, lots of carbonates like baker and baroque dolomite. Obviously, these will not work either.

Hi. I visited an Indian trading post near Four Corners, NM, and one of the sellers told me that the rocks that they sell with drawings on them are flint, and will throw sparks when struck with a fire steel. They did not have any blank rocks, but they said that the flint was very hard to find in the outcrops, most of the rock being sandstone. I found some rocks which looked promising, but they did not create sparks when struck with a file tip. Is this a valid test? Does this kind of flint throw sparks? Is there a good test or way of recognizing flint that is usable with a fire steel? I'm just curious. The only thing I have gotten sparks from is mischmetal.

Nice block. This is inspiring. FlyingXS, that is a good idea. I might try a partial through hold for a plug weld, but this may warp the plates.

I have this problem too. The bad thing is that the creeping white shadow does not appear for months and is only visible after installation. Often, it is so slow that the customer does not notice until a guest asks "what's that white stuff?" Does acid really work?

It is not 1040. 1040 will show more bursts. The picture is not very clear. 1" from a scrapyard could be almost anything. If it is 1.5", it would be most likely 1045. Do you have coupons for comparison? I have about 15 different alloys, and sometimes I can nail it so good that I can sell it on Ebay without worrying about bad feedback, and sometimes I am just stumped. I bought a block for a fabricated anvil, and the scrap yard told me that it was not mild steel "because of the way it rusted". It did not match any of my coupons. I shaved off a bit and heat treat tested it. Not hard. That's all that mattered, and it was just for curiosity. That block is now a good anvil, with a 1060 table and a 4140 horn.

Not easy, and I would suspect that your electronics teacher does not know how much difficulty this project entails. Why don't you start small and make a demonstration version. I was just talking to someone who was tasked with developing an induction heater that would take a piece of steel up to 2000 F. I was kind of skeptical, since he said that he did it in an afternoon. I asked him how he got the steel above the Curie point. He said that it was very straightforward. Set up the PWM of the half bridge converter so that it is driven from the feedback of the output coil. That makes it track the maximum power point as the resonant frequency changes. He told me that this is only one op amp, and it is only difficult if you don't know what you are doing. He did say that his converter was low power and multi-killowat units were challenging because of all the parasitics. If you are doing less than 100 watts, designing a demo unit is fairly straightforward.

Joining a blacksmith association is money well spent. At least it has worked out pretty well for me and my buddies. As for horizontal vs vertical and observations of rebound, you should be aware that rebound does not necessarily imply efficiency. Count the blows required to taper a piece of 1/2" square in both orientations. Try alternating. The results may be interesting. That doesn't mean that I don't like horizontal. I have two railroad track anvils. The vertical one is great for all kinds of forging. The horizontal one is good for straightening sheet metal and flattening pipe ends.

I hate drilling hard steel or work hardening steel. Usually, I will just hot punch it. There are two ways that have been successful for me. First, sub-critical anneal, a propane torch is sufficient. Second, using a big 3/4" drill that only runs at a few hundred RPM rigged up as an "old man". The 2x3 lever and chain makes more difference than the RPM. There are two tricks that I haven't tried, since I just bought a drill press (my first one!). Try drilling with a piece of mild steel or a bad drill bit until the hole gets real hot. Then let it cool and use a regular bit. I am sure that this will work, since I have an antique carbon steel drill bit that got hot, and it just mangled the tip. Since it was a garage sale bit, I did not figure it out until I did a spark test. Oh well, it will be the bit of a hatchet or hardy tool now. The second trick is to use an Artu drill. I have never seen one of these work in person, but there are videos. Basically, you run it hot and fast with a lot of pressure and no lube. The brazing on the carbide will give way at about 1000 degrees, but the sales guy said that the steel will will be toast by then. Has anybody else tried this? It seems that it should work.

Some tongs break at the rein weld, due to either grain growth, bad weld, stress riser, or corrosion.

Hi. I pretty much agree with Brian. I made a few of the loop and cut type pokers, without upsetting for the join point, and they look unsatisfying. I have also destructively tested a few and they are surprisingly strong. The welds are definitely not x-ray quality, since I have taken one apart, and it was pretty bad, maybe 30% inclusions. No matter, the joint will probably break at the wasted area just outside the weld anyway. One of my customers said that my poker worked fine in the fire, but he also used it to hook toolboxes out of his truck box. He said he was surprised it hasn't broken yet, since if the toolbox catches on something, he will yank until it comes out. This kind of abuse stretches the weak area, which is pretty strong in tension. Prying, bending or hammering the area will usually make it fail, but it does not normally happen in the field. As to whether this is a good idea for beginners, hmmm, I'm not really sure. I see the point. Colleagues tell me that good forging practice does not make money. Intentionally engineering in stress risers so that the product fails before its time makes money.

Hi. Thanks for the comments. It does not point as well as I'd like. It will point correctly in the wind, but a small fan will not spin it. The tube bearing was made by fullering pipe, then melting a button of brass in the end. It spun well when the pivot was sharp, but will wear down to a blunt point which doesn't spin so well. It was also found to be sensitive to the alignment. The slightest bit off level and the barrel will foul on the shaft. I will not be in charge of the installation, so I warned them to make sure it is level. Miclael, since you are in the Bay Area, you can come out and see it after it is installed. The target date is in May

I finished the weathervane that I inquired about here. The suggestions from John B were especially useful. I decided to do it all traditionally, and only used arc welding to do some fixturing. The key joint was the collar for the direction pointers. It was made out of flat bar pierced in 4 directions and rolled into a square. The NSEW rods were put in the holes and it was heated in the center of a coal fire. It was then fluxed with borax and touched with a brass key at the right time. The fire was then allowed to die down and the finished item was quenched and removed. It worked and looked great! It shifted a little in the fire, so that gave me an opportunity to do some strength testing. The other tricky part was affixing the sheet metal cutout to the direction arrow. This was done partially with collars, but these proved too flimsy. They also attach at the weakest point. So, a sled was cut out of thicker angle iron and cold rivetted to the sheet metal. Then, the sled was hot rivetted to a clip that was raised from the direction arrow (horseshoe style). Finally, the front of the sled was affixed with a U-shaped pierced clamp and tightened with a wedge through the holes bearing against the sled and the arrow. It worked out tight and strong, but I was surprised at the lack of details that most web searches brought up on methods that don't use arc welding. Attached is a picture.

I have a large Hay Budden which is over 3" thick at the hardy hole. This is safe for anything that won't damage a standard 1 and 1/8" hardy tool. My smaller anvil (about 90) only has about 1" or so, and it is not safe with even aggressive hand hammering. I would not worry about the less demanding uses, such as cutting, bending with a fork, welding in a round bottom swage, or using a block tool. I would not use a cupping tool to form the rounded end on a hammer. This is above the safe limit.

These questions require understanding the mechanical properties of the material and are beyond the scope of simple applications of the conservation of energy and momentum. The next installment should shed some light on this topic. Briefly, one is pretty much safe as long as the maximum impact stress is less than the elastic limit of the material. Otherwise, there is a risk of leaving a dent. The maximum impact stress is a function of the hammer momentum (not energy) and contact area. That is why the radius of the edge is important. The article had some use to me. It helped me figure out what size of anvil to make/buy. It helped me understand why putting silicone rubber under the anvil to quiet it down wasn't such a bad idea. It did not sap all of the precious hand hammering energy. It helped in the construction of my latest fabricated anvil in that it didn't have to be over-welded. Theoretical does not have to mean useless. Some people over at anvilfire said welding was a waste, because it used so much electricity and it was not worth welding up an anvil. Looking up some welding guides gave some theoretical breakdowns of labor vs electricity costs per pound of deposit for different electrodes. Now, these guys over at anvilfire have way more hood time than I do, but a simple test backed up by smart meter data proved them wrong. Now, a lot of armchair experts will insist that those smart meters are inaccurate, but it agreed with the theoretical deposition tables. I would say that theory had proved itself against "the experts". It reminds me of what I told an engineer. Your design failed in Spice, then it failed on the bench, and then it failed in the prototype. What more do you want?

Hi Gerald and others. Physics definitely has applications. But, sometimes they are far removed from the task at hand. Many years ago, I was hanging out with a physics professor who was installing a 3 story tall particle accelerator. The installation was kind of tricky, because these things are top heavy, kind of like a power hammer. I asked him if it was like moving a power hammer, and if he was doing calculations. He said that the riggers do all that, and they should do fine. It would not be done in a day or even a month. So he didn't have any role? Well, he said, if the riggers get in trouble, they will call the engineers. And, if the engineers get in trouble, they will call the physicists. I asked him if that happens much, and he said hopefully not. But there is one famous time that the engineers got in trouble and had to call the physicists. That was the o-ring low temperature failure that let to one of the greatest space exploration disasters in history, and it had to be diagnosed by a physicist. I talked to another physicist about this, a fellow who did not have much good to say about the investigator. He said that many engineers could have solved the problem but they were held back by a cultural problem. Seems that there is a big problem with mistaking skepticism for intelligence. As for practical applications of the hammer and anvil calculations, here are some: 1. There are two numbers given from two different calculations. One of them says that a bigger anvil is needed for the same efficiency. The cost difference between the two calculations is not trivial. As I recall, there is a factor of 4 there. What the inelastic model says is that you do not need as much mass as previously thought to attain decent efficiency. In fact, there is even some efficiency at 1:1 ratios. In other words, if you suspend a 2 lb hammer on a thread and strike a target up against it with a 2 lb hammer, you will do some work. The elastic model says all energy will be lost. This is clearly wrong. And it can easily be demonstrated with a string, a couple hammers and a finger (or piece of modeling clay). Interestingly, it was not a physicist who introduced me to this idea. It was a blacksmith, the web personality FredlyFX, who I met at a CBA spring conference. This observation contradicts the figuring from the guru at anvilfire. The distinction is not trivial. It is the difference between wanting a 400 lb anvil vs a 100 lb anvil. 2. As was correctly pointed out, the model does not account for anvil strength. That was considered a fatal flaw, since the idea of the rubber anvil was brought up. Far from being fatal, it highlights the importance of thinking of efficiency as the battle against energy loss. There are all sorts of ways that energy can be lost, but by doing the calculation, the maximum energy loss due to low mass ratio can be calculated. This is incredibly valuable. Once the mass ratio is brought to the desired value, it can be ignored when the question of material strength is asked. This meta-analysis is called decoupling. In other words, one can make the statement that when the anvil is less than 100 lb, material strength is not so much a worry, since too much energy is lost in the mass moving, while at greater weights, attention can now be directed to the material strentgh. 3. There has been an excessive focus on the limitations and assumptions of the model rather than its (rather simplistic) conclusions. One important thing that it shows me, which I did not realize until doing a couple of web searches, is that it is also useful to ask where does the lost energy go? Does it disappear into thin air? No! The emphasis on conservation of energy in the model directs us to ask this question, which is more important for power hammers. The energy, even if it is only a few percent, goes into movement of the anvil. In a power hammer, this is transferred to the foundation and creates noise and nuisance vibrations. There is one company which analyzes this transfer and recommends its padding instead of increasing the anvil mass. Why? Increasing the anvil mass helps, but it reaches a point of diminishing returns quickly. The model beautifully illustrates this. In the end, it is cheaper to buy a dissipative rubber pad whose main function is to waste energy. But the naysayer will complain that energy wasted is money wasted. The manufacturer uses the model to show that this wastage is limited as the conservation of momentum and energy show. The object is not to harness this energy, but to keep it out of the foundation, where it can cause problems. In that way, I think that skepticism is less a measure of intelligence than is the rational quest to save money without accepting mediocrity. 4. Left as an exercise to the reader: these calculations provide the foundation for more advanced observations, including three which might be of interest in the blacksmithing community. How hard does the top have to be (yield stress), what is the effect of anchoring the anvil on a softer substrate, what is the loss associated with a lose top, and what is the loss associated with off center blows whose axes miss the center of mass. One of the questions that always comes up is why is a full pen weld needed to join a hardened top to the anvil body. A naysayer will complain that any porosity in the weld renders it useless for this purpose. This paper will help the enlightened reader understand that rarely is the problem black and white, and there are other more cost effective ways that ignore the non-full pen weld after its contribution to loss drops below a certain threshold.

It is a worst case analysis. Any support will increase the efficiency.

It is useful knowledge in that it provides a pessimistic estimate (or worst case). Any connection whatsoever to the earth will act to improve the efficiency. So, if an efficiency number of 92% is computed, a naysayer cannot jump in and say it must be less than 80% if the anvil is sitting on anything, even a rubber pad. He can reply that it must be higher than 92% since the anvil is welded to an I'beam which is buried 8 feet into solid ground, but the model does not address that side. Therefore, this model is not very useful for those little 25 lb striking blocks that seem to work so well with 12 lb. sledge hammers. That is not the place to apply it.

No need to be skeptical. Just understand the limitations of the simplified analysis. The paper considers a freely suspended anvil (not anchored). All the lost energy goes into moving the anvil. For the first calculation, full rebound, there is a hidden assumption of no anvil deformation, because a point mass cannot store energy in its deformation. The similar is true for the second calculation, but with the empirical observation of the coefficient of restitution, the additional assumption is introduced that most of the deformation is in the target (hot metal). This conclusion does not follow from the analysis! It is an experimental observation from industrial forging processes. That is why it is so annoying to have a missing bibliography. Most industrial forging processes occur at e = 0.1 - 0.2. This is much closer to full stick than full rebound. Most beginners and finish forging processes are at 0.8 or worse. These numbers can be searched on the Internet, but they are only tabulated for large industrial forging hammers.

Hi Gerald. The analysis assumes no contact between anvil and earth. Thus, it produces an pessimistic answer (underestimate of efficiency). Accounting for a connection is not trivial. This calculation is significantly beyond the textbook applications of conservation of energy and momentum. Before calculations of this type are made, the hammer-anvil impact force needs to be estimated. This estimation will open the door to the above and other interesting statements, and will appear in the second and forthcoming parts of the paper. A significantly simplified and more approachable set of articles is running in the CBA magazine as well as some other local publications. As expected, they have attracted quite a bit of controversy, primarily due to the author's gaps in clarity and anticipation of the kinds of questions. There should be another installment appearing soon, perhaps in the next issue.

A good starting point for those who are interested in the physics is "Physics of Anvils"

What is the cutting capacity of one of these anvil shears? As good as the Beverly?