That is why it is called a mechanical advantage.Īnvil size is not as critical. and a power hammer can hit a lot harder than a human. I would agree with the statement about the power hammer and a ratio. Its mass allows me to hammer sideways on occasion and it tends not to budge, I seldom use hand hammers weighing more than 3 pounds. My final purchase was a very large European anvil and I love its huge sweet spot (aka thick waist) and its massive top surface. I have used many different anvils for hand forging over the years. The Massey Clearspace hammers from the UK were perhaps an exception. Most of the old tyme power hammers had too little anvil IMHO. Thus,over time I have kept increasing anvil mass with improved "feel" and I rather expect that going higher would add the effect with some diminishing returns, My littlest 50 pound hammer has a 25:1 ratio, but I have never built that unit with less anvil mass and cannot really say anything about mass change effects. I moved on to better hammer designs before I did any anvil changing, and the better hammer designs used centered guides for much better control and rebound/percussion effects. Way back in time I made I-beam spine hammers with a much lower ratio of about 8:1. My experience with my power hammers is that 20:1 makes a more fun hammer than with the previous 16:1. The Soderfors also shows no sway or marking on the face but there are some chips out of the edges. A bearing doesn't rebound as well from the Trenton as the Soderfors either. Trenton ad the Trenton has a taller waist so there's more iron under the blow but it's a soft wrought body. Soderfors moves metal FAR better than my 200lb. Other than damage the anvil hammer ratio isn't such a big deal except for efficiency and overall hardness has almost as much to do with it as weight under the blow. Chipping edges doesn't have as much to do with hammer weight but the heavier the hammer the more likely and more severe the edge chipping so don't miss. So, I THINK using too heavy a hammer on a soft bodied anvil, especially if it's a light weight or thin faced one could result in eventual sway damage. I have seen a couple swayed anvils I THINK may be erosive wear but I don't know about the mechanics of that. I've never seen it in a Swedish cast steel anvil that hasn't been through a fire or such. I've seen this most commonly in wrought body anvils but some cast bodies too. Sway is (IMHO) caused primarily by deformation of the anvil below the face steel. The cause of edge damage is pretty obvious, though I'm sure some clever folk have come up with other methods. I only see two types of anvil damage on healthy anvil. The only legitimate hammer:anvil ratio I've seen raw data for is the power hammer ratio. Striker, horn, and hardie work are of course exceptions to this. One experianced guy working with a hand hammer is unlikely to damage any reasonably sized anvil, so if anone thinks they are suffering due to small anvil syndrome pratice more and slowly work up to a bigger hammer. However, when hand forging your strength, endurance, technique, and hammer size are as important as anvil size. If you work on the horn or in a swedge in the hardie hole, (or do much of anything more than forging a simple taper or beveling a blade) there is significantly less mass under the hammer and the overall mass of the anvil would need to go up if you wanted to maintain mass under the hammer. On a hand forging anvil this is not true. On a power hammer all of the anvil mass is directly below the hammer head. There is also a link somewhere here to a Japanese engineering paper placing the ideal ratio somewhat lower. The gist of the chart is that minimum shoud be about 10:1, there are diminishing returns beyond 20:1, and 15:1 seemed to be a sweet spot on the cost/benifit curve. showing POWER HAMMER tup to anvil ratios. There are a few threads on this in the power hammers section, and in those threads are refrenced a chart from Chambersburg Engineering Co. I realize a definitive paper is most likely not available but with enough people looking and discussing the subject we should be able to sort it all out. What is the original source? Who made or chose the numbers? I am looking for where all this started, the research that determined the *correct* size ratio. I have also seen comments that 3 and 4 pound hammers can be used but not for constant use as it will start to deform the anvil.ĭid someone long, or not so long, ago threw a guess into the air?ĭid it take hold like a urban legend and every one else repeat the number because it sounded like it had validity? Or is there research to prove the number? This is suppose to be the *correct* ratio as to not damage the anvil with use. That is a 2 pound hammer on a 100 pound anvil. I have seen where a hand hammer should be 2 percent of the anvil weight. There has been a lot of numbers thrown around for anvil size and hammer size.
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