Ferguson

I visited Bruce M., and looked at his system. He uses simple bolt on dies. He literally has 100 different dies. The simple bolt on dies can be easily made as needed, and changed quickly using a impact wrench. He does not like spring dies in power hammers, says that they are very noisy and tend to break. I am going to try to attach a couple of photos from Bruce's shop. Bruce's approach made a lot of sense to me. Richard

Thanks to all for their comments. Bruce M. invited me to visit his shop, where I understand he uses bolted on dies. I will try to post a photo after I visit, and also explain how he uses those dies, how or if he uses spring dies, etc. Richard

I am back to looking at building a power hammer, probably a 35 pound "new Kinyon" style. I have good welding equipment and a small lathe, but no access to a milling machine. My question relates to dies. As far as I can see, commercial hammers generally use dovetail dies. Flat dies seem more common for homemade hammers, especially treadle hamers. With flat dies, what do people do for working stock down? I have seen one hammer with flat dies which used a "wedge" with a slight taper, set on the bottom die to facilitate making tapers. I understand that flat dies are easier to use with spring dies, which makes sense. Some people have some provision for having spring dies drop into a square hole, so the spring die stays in place without one having to hold it. I think that I have seen some examples of people using flat dies and then bolting on home made dies. The examples I have seen have the bolt holes on the top of the die, which means that the flat die has holes in it. I was thinking of putting the bolt holes on the side, but I imagine that there would be some disadvantages of that. Do people have hammers with flat dies and no provision to bolt on dies? Since I don't have a mill, the dovetail dies might be impractical in that I would not be able to make my own dies. I like to make my own tools. So maybe I need to stick to flat dies just for that reason. Pointers to useful web sites or previous discussions would be great, as I did not come up with anything in my own searches. As an aside, what do people do to keep the bolts on their hammers from coming apart with vibration? Locktite? Wired bolts like on an old motorcycle? Tack weld the heads? Thanks in advance. Richard

I have been to a Monastery in France which had a waterwheel driven power hammer dating from 1220 AD, reconstructed now. So power hammers have been around for a while. http://www.sacred-destinations.com/france/fontenay-abbey http://www.fr.francethisway.com/abbeyfontenay.php - In French, but claims it was the first hydraulically driven power hammer I remember when I was there seeing a plaque from a French engineering society, so they regarded it as significant. The reconstructed hammer has a 200 pound head. I have not seen anything definitive on where the first blacksmith power hammer was built. Wikipedia claims the earliest trip hammers date from ancient Roman times, or ancient china, but this may have been for mining use, breaking up rock, rather than blacksmithing. Richard

I am going to make an assertion that I am not 100% sure is right. My assertion is that for a hammer to hit less hard it will strike fewer blows per minute. I believe that to be true of the traditional mechanical hammers as well as the home built Kinyon style air hammer. The mechanical hammers have a slip clutch, and light blows are the result of slipping the clutch, so fewer hits per minute. If the Kinyon style air hammer is throttled through the exhaust valve, then the head will move slowly, meaning that it will take longer to go from the bottom or top of the stroke to where it resets the microswitch. However, the self-contained air hammers work on a different principle, and I believe that they operate at the same BPM when hitting softly and hitting hard. I would believe that would be an advantage of the self-contained hammers. I would be interested to see if people with experience on these hammers would confirm or deny my assertions. Richard

A VFD is a variable frequency drive. These would usually be used to adjust the rpm of an AC motor. It turns out that many of the VFDs have an additional feature, which is generating three phase output from single phase input. Some will accept single phase or three phase input power. I think that one of the other posters mentioned that you might need to derate (oversize) the VFD if you use single phase input. As I understand them, they work by rapidly switching the power on and off the approximate the usual sine wave AC power. Anyway, I think that if you check it out you will find that it is probably cheaper to buy a VFD than a big 3 phase motor and convert it into an rotary phase converter. One interesting thing about VFDs is they generally recommend that you remove all the other controls, relays, etc., and let the VFD do everything. If you put a switch between the VFD and the motor and open the switch it might blow up the VFD, as I understand it. If it was me, I would probably carefully document the wiring as you received it, and then disconnect the wires from the motor to the existing controls. Not sure if there is much value in the variable motor speed in this application, but you might find that changing the speed up or down makes it run more to your liking. Those who buy self-contained hammers from countries with 50 hz power, and run them in the US with 60 hz power, sometimes change out the pulleys to get the hammer speed back to where it would have been with 50 hz power. VFDs have many sophisticated features, such as soft starts, but not sure how valuable any of those features would be in this application. Link to How a VFD works Richard

Very nice. Thanks for the video. I have a maintainability question. I have thought that it would be advantageous to bolt the anvil to the base, and then wire the bolts to keep them in place. What would happen if you had to replace the tup? Would you just grind out the welds holding the anvil in place? How big are those welds? What do you figure that the whole thing weighs? I guess the other advantage of bolting the anvil to the base would be the ability to break it down for transportation. I understand that you have some ability to tune the alignment of the dies via the bolts on the side of the tubing that the head assembly runs in, which I understand push on the plate that holds the UHMW. I was not clear on which bolt did what. I was thinking that the upper and lower bolts permitted aligning the head, but I think that you said that those only located the UHMW plate. But if you only have left right bolts for alignment, how would you adjust it in the other axis? Richard

I looked harder, and found the Anyang web site, rather than the site of the US distributor. They show hammers up to 2000kg head weight (4400 pounds). As you say, it is a matter of your pocketbook, the big hammers are available, but not imported on a regular basis. Anyang hammer web site Richard

I was wondering what is the biggest blacksmith power hammer in production today? I noticed that Anyang, Sahinler, and Iron Kiss top out around 150 pound head weight. Obviously the Nazel hammers were much larger than 150 pounds, but I understand that production ceased in 1973. If somebody needed a large hammer, would they need to find an old hammer, and probably rebuild it? Or maybe there is somebody in Europe or Asia building huge hammers. For purposes of this discussion I would lump mechanical, self-contained air, and utility air hammers together, and just measure the hammer by the weight of the head. It looks like most of the commercial hammers are self-contained air hammers, which I understand would include the Nazel hammers. This is purely an idle curiosity question, as I have no need for large power hammer. Richard

Look for push-pull cables, the links below may help. Some of the cables have 6 inch travel, might suit your needs. push pull cables These guys have cable with a galvanized steel sheath, better than plastic in a blacksmithing situation. More cables You could make a remote pedal/treadle, and hook it up with the cable to your main treadle. Note that although some of these cables can both push and pull, they are naturally stronger when used to pull, so better to design the cable as pulling when you push on the pedal. I doubt if you need a custom cable, look for a stock cable. On the other hand, some of these companies may have a small minimum charge for a custom cable, just pick a standard style and tell them how many feet you want. On my sheet medal power hammer, I use a bicycle brake or shift cable and a home made pedal and linkage, works fine, operates a trigger valve, I have a spring return on the trigger valve. How much cable you need depends on how much force you need to operate the main treadle. I can position the pedal where it is most convenient. In this case, it is my only pedal. Richard

In my past life, I saw some very nice lifts that used vacuum, as far as I can tell. The vacuum was connected to suction cups to grip the part, and as far as I can recall, the vacuum also provided the lift. We are talking things in the 100 pound range, I believe. Obviously you would not want or need suction cups, but the advantage of this lift over conventional cable or chain lifts was that a little force moved it up and down and back and forth. Very slick, very user friendly. The shop people really used them, which is the test of how good they were. The system below appears to be the same as the one I remember. Vacuum tube lift I hate push around lifts, way too hard to push. Awful things. Get a walkie type forklift with power travel and lift. They can be fairly compact. You can get both forks and a lifting hook, easy to change out as needed. But these vacuum lifts are the only things that I have seen that deal with varying weights yet allow you to position the load easily. An alternative to electronics would be a mechanical cable system, connecting the remote foot pedal to the main hammer treadle. I would bet that would be cheaper and probably simpler to implement. The advantage of linear electronic control would be you could probably have a relatively short travel for the foot pedal. You should think about a quick disconnect system for whatever you do, so you can restore the hammer to basic treadle operation. Richard

It looks like the students did a lot of testing, but they were weak in terms of usable conclusions. Others have commented how their presentation required magnification to read, but maybe their real goal was a large poster, not something internet friendly. Are they saying that the wooden handle hammer had more vibrations than the other types of handles? And that the metal hammer had less harmful frequency vibrations? By superimposing the graphs it was almost impossible to read the accelerometer graph. The frequency distribution graph was more or less readable. Three graphs side by side would have been a lot more readable. But other than criticizing the report and its format, what usable information can we get from this? Richard

What is an electric acid gun? Richard

I use "incralac" to protect my shiny copper art. It maintains the shiny finish for years. The prep is very extensive, involving sanding, alcohol, rubber gloves, more sanding, and then spraying it with incralac before it has time to oxidize. If you do it all very carefully, the results will be good. Copper will oxidize if you look at it crooked, so you need to be very careful. I believe that there are other coatings available, such as Permalac, but I have not used them. Richard

I can see the advantage of linking the position of the microswitches to the foot pedal. Is it the Bull controls that use one microswitch, whose position is linked to the foot pedal? In some cases, that would allow a "clamp" function, if you hold the pedal down to the bottom. Not sure how useful the clamp position might be, seems like you could lose all the heat in the work while clamped. Perhaps more importantly, the hammer would tend to have a wider opening, especially at partial throttle, which could be very useful. I would expect that the head would go almost all the way up if you took your foot off the pedal. I can also see the advantage of some kind of adjustment to the microswitch position, maybe move the switch up when using tooling, for example. Or maybe just to allow some tuning. If one would combine the adjustable microswitch positon with the linking of the microswitch to the foot pedal, I would think that this would provide quite a bit of performance and flexibility. For light taps you only push the pedal down until the head just touches the work. The head travel would increase the further that you push the pedal down. Properly adjusted, the head upper position might stay roughly constant, while the head lower position would be proportional to pedal position. Without tying the microswitches to the foot pedal, the upper position of the head would be near the center if the pedal was only pushed down partway. The upper position of the head would only approach the upper limit when the pedal was more or less wide open, since the microswitch position would need to be near the center of the travel to avoid destroying the hammer. For heavier hitting you push further, and the head would be moving fast when it hits the work, especially since the throttle valve would be open further. Adding the two microswitches could increase the speed of the head when it impacts the work, because that would increase the head travel, giving the head more time to accelerate before the valve reverses. This would mean that the head would be powered almost all the way down, instead of reversing the control valve earlier, which would decelerate the head before the hit. For the absolute maximum hit, one would want the lower microswitch to reverse the control valve right before the head contacts the work. The upper microswitch would be set primarily to protect the hammer head from traveling too high, potentially damaging the hammer. But there is something missing with this analysis. This relates to the spring effect of the air in the cylinder. Note that some people have mentioned the advantage of having a check valve between the air supply and the control valve. (I think that is where they put the check valve). That check valve converts the air in the cylinder to a spring, providing additional force to reverse the direction of the head. Think about it this way, assuming a nominal air pressure of 100 psi. If there is no check valve, the maximum force to reverse the head direction is 100 psi times the cylinder area. (disregarding any pressure drop through the control valve). Air could potentially get pumped back from the cylinder into the supply line, a waste of energy. If you add a check valve, the pressure in the cylinder would probably go over 100 psi when the head direction reverses, providing additional force to accelerate the head, at least as long as the pressure remains over 100 psi. One possible concern would be the pressure rating of the control valve; I am not sure if the commonly used control valves are rated to operate above 100 psi. Not sure how high the pressure could go; One might need to figure out a way to measure the peak pressure. The air spring effect might also tend to act as a cushion to protect the cylinder and the hammer from high forces if the head hits a mechanical stop in the up direction. The spring effect would also increase the number of hits per minute, by speeding up the reversal of the head direction. After all, the work that the hammer can do is not just a function of the strength of the hit, but also a function of the number of hits per minute. If you had really strong hits, but only 60 hits per minute, that might not really be the best approach. You might be better off with slightly softer hits, but 120 hits per minute. A higher hit rate, but lower hit strength, might provide more control, even providing a planishing effect. To achieve a higher hit rate, one would presumably want to reduce the maximum travel by setting the two microswitches to operate at the same time. Note that the new Kinyon design adds a leaf spring to the system, which would add an additional spring effect to the system. Many helve hammers depend greatly on the spring coupling the eccentric (driven by the motor) to the arm. Many mechanical blacksmith hammers have a spring as well. (The little Giant hammers come to mind). I wrote an article about tuning helve hammers, pointing out that the resonant frequency of the head/spring system needed to match the maximum rpm of the eccentric, to achieve maximum hit strength. Tuning helve hammers This discussion thread is useful insofar as it forces both of us to think through how the pneumatics really work, and how they should work. Richard

Ok, so my assumptions were correct. I just noticed that the control arm is actually a telescoping arm. Setting aside the question of the mechanism that you use to get "slow and hard", what is happening there? Is the head going down rapidly but then up slowly? The control valve is not a proportional device, it is a two-position device, so hard to see how that could be done, without introducing check valves and metering valves. I understand that the control valve position only changes if the two sides of the pilot have different pressures. Similarly, the microswitches are also two position devices, not proportional controls. Putting on my engineering hat, any system using a two position control valve inevitably has a "bang-bang" control system, with some kind of hysteresis. In this context, hysteresis means that operation point in one direction is not the same as the operation point in the other direction. The furnace thermostat in your house has hysteresis, it might come on at 65 degrees, but not turn off until 67 degrees, a two degree hysteresis. Even with a single microswitch, the microswitch has internal hysteresis. Hysteresis is not necessarily a bad thing. Usually, some hysteresis is desired to reduce instability. As far as I can see, a system with two microswitches would allow a larger band of Hysteresis, and would allow adjustment of the hysteresis. If the two switches do not operate at the same time, that means that the head is driven in one direction longer before the valve reverses position. In fact, with a two pilot control valve, it does not matter if both sides are zero pressure or both sides are the same positive pressure, the result is the same, the valve stays where it was. If you had a simple control system, with two fixed microswitches, it would not matter which one was above the other; if the two microswitches do not operate at the same time, that increases the hysteresis, and the head travel. The mechanism that you have designed is obviously functional, but is somewhat complex. My concern would be that the more adjustments that something has, the harder it is to understand and to adjust, and the more likely that the user could mess it up by setting one control to the wrong position, and then adjusting another control to compensate, etc., ending up very far from the optimum solution. This is often a problem with commercial machines, where at least you know that the machine can be adjusted to operate correctly. This could be a bigger problem with home made machines, where the design and the adjustments might be such that it would be impossible to adjust it to operate correctly. Richard

I just looked at both videos right now. I had looked at the control video before. I confess that I did not find your explanation very clear. Let me see state what I think that I know, including some things about which I am in doubt. The upper end of the control arm is coupled to the head position. The lower end of the control arm is coupled to the treadle position. You are using a two position, two pilot control valve, without a spring return. When you push on the treadle you are both increasing the travel and changing the "center" position. (I will define the center position as the head position that is halfway between the two microswitch operation points). (By the way, I would see that as the primary advantage of the control arm system that you use). The treadle is also coupled to an exhaust valve, as in the simple Kinyon control system. As far as questions, I have a few. I saw that you had some adjustment points to tune the hammer operation, but I was completely unclear on what those adjustment points affected, and how. How did you adjust the hammer for "hard and slow"? I am asking both how you do it conceptually, as well as what adjustment causes that to happen. The concept of hard and slow seems like an oxymoron, but presumably I am missing something. I noticed that Ron Kinyon's comments suggested that a two microswitch control system might be best suited to a hammer with a lot of head travel, more than 10 inches. Richard

Richard; Most hammers work well with the simple solution, one limit switch and a spring return one pilot main valve. On hammers of 12-16 in stroke I use, two limits, 2 pilot main valve no center position. The dwell time between switches allows for full travel of the stroke at a higher speed. In flagstaff in 2000 I showed a one limit valve on a slide hooked to the foot pedal Little Giant style hoop pedal. Pushing the pedal all the way down would clamp the dies If you use 2 limit switches make room for them to be moved manually in tandem. I slide my limit to the top of its slide and use the hammer like a treadle hammer because it can't make a full stroke. I have not used the clamp mode much, most cases I am drawing out stock or using tooling on the dies. In most cases the tandem limits are on top of each other maybe a 3" gap using the ARO small limit valves. I have used the Norgren 500 valves for 22 years as the main valve and had only one fail in service. what size cylinder and stroke are you using, what head weight? Old style Kinyon or Mark2 with the beam? Feel free to post my response. Cheers Ron Kinyon -----Original Message----- From: Richard Ferguson To: ron kinyon Sent: Sat, Apr 2, 2011 10:18 am Subject: Hammer - pneumatic questions Ron: I asked these questions on the iforgeiron.com website, and no one had an answer. Somebody sent me an email suggesting that I ask you those questions. If you go with two limit switches, do you then buy a three position valve? I think that you can buy two position valves with two pilots and no spring, or three position valves with two pilots and a spring center return. The three position valves might have all ports blocked in the center position, is that an advantage? Why? Would that conserve air? If you only had a two position valve, what is the advantage of the two pilots with two switches vs. a single switch and a spring return? I can see that two limit switches provides a bit more flexibility. Having the limit switch position tied to the treadle in some way adds complexity, but some advantages as well. No matter what arrangement you use, would you still need to manually adjust the limit switch position if you wanted to use taller tooling, at least if you wanted full power with taller tooling. I would of course appreciate any comments. With your permission, I would post your answer on the site. Thanks, Richard Ferguson

The gauge needs to be shock mounted in some way. Not sure the best way to do it. Use a flexible hose to the gauge, and rubber mounts to decouple it from the frame. The link below is one company making shock mounts. These are for weights similar to the gauge. Richard shock mounts

Very nice. Good process description. It seems like for power hammer tooling, it is fairly common to heat up a part, hammer it with some cold shape, and then produce a texture or pattern on the part. Then that part becomes tooling, and can be used to texture or even make a shape like the cold shape that you started with. Makes me want a power hammer...... Richard

I will second the stainless steel. I saw a guy wear himself out forging 3/4 inch diameter stainless down to maybe 3/8 inch. He was only drawing out a few inches, and that was with a good power hammer. He literally had to sit down, and he quit after making one piece. Now this guy has a regular job, so does not forge every day. But it was impressive how hard he had to work to get it done. He was trying to help me out on a project, and after I saw how hard it was to make one, I rethought the design and fabricated several of them out of pieces welded together. The limited work that I have done with stainless would support stainless as a common material that is hard to do anything with. The only part that I found easy was welding it. Richard

I have a few general questions. I had asked these questions in another thread, but I think the questions got buried. If you use a 2 inch cylinder, how large are the ports? 3/8"? Where can you buy cylinders with large ports? How much? I noticed that most 2 inch standard air cylinders have smallish ports, maybe 1/4 NPT. Sounds like cushions are a good idea for the cylinder, maybe even adjustable cushions. If you go with two limit switches, do you then buy a three position valve? I think that you can buy two position valves with two pilots and no spring, or three position valves with two pilots and a spring center return. The three position valves might have all ports blocked in the center position, is that an advantage? Why? Would that conserve air? If you only had a two position valve, what is the advantage of the two pilots with two switches vs. a single switch and a spring return? I can see that two limit switches provides a bit more flexibility, especially in adjusting the head travel. In the standard setup with one microswitch and a spool valve with a spring return, what determines the travel of the head? Having the limit switch position tied to the treadle in some way adds complexity, but some advantages as well. No matter what arrangement you use, you might still need to manually adjust the limit switch position if you wanted to use taller tooling, at least if you wanted full power with taller tooling. Focusing on the new design, the advantage of the new Kinyon design is mostly lower height and fewer alignment problems with the cylinder, right? I know that the spring adds some "whip", but only if it is tuned correctly. If you want to understand how to "tune" the spring of the hammer, take a look at this article, addresses mechanically driven helve hammers but applies to this design as well, due to the spring. Hammer tuning Richard

I really appreciate you guys clarifying this for me. The key, then, is a tapered nail in a tapered hole, and making the sizes line up such that a certain amount of the nail sticks out above the header, and that amount is what you hammer and make into the head. The header never goes into the fire, I suppose, just sits on the anvil. How thick is the header relative to the stock? Sounds like the sizing of the nail vs. the hole would be the critical part. Hammer too little, and you have too much sticking out, hammer too much, and you don't have enough sticking out to make a head. But maybe that goes back to the idea that the header hole is just a bit smaller than the stock, so the care goes into making the header more than the nail. I like the idea that one puts the spike into the hole, then marks the cut point, makes it all less critical. If the spike is too short, hammer it a bit more to make it longer, if the spike is too long, cut off the end on the hot cut and then hit the new end a bit to taper it. I have been doing quite a bit of drifting lately, so I understand the concept of tapered holes and a tapered spike. It is reversed in that in drifting, the hole (work) is hot and the drift is cold, while in heading, the header stays cold, and the spike or nail is hot. When the nail or spike cools down, I would imagine that it would be pretty easy to drive it out of the header, or maybe that is done hot. Thanks, Richard

I am going to ask a basic question, which is how the header works. Does it line up with your hardy hole? What keeps the spike from falling through? Richard

It is a clever and unique solution, but I wonder why you did not do the obvious, which is to set the gantry on the ground, lift up the hammer, and then drive the trailer under the hammer. I admit that would require some backing skills, but that seems manageable, given that you could take several tries until you got the trailer lined up. Those gantries are usually wide enough to allow that. Richard