patrick

Michael, I'm surprised you're having trouble with that motor and would have to agree that something else in your system is probably the cause of your problems. My hammer, though tagged as a 300 lb machine has an actual ram weight of 460#. The drive pully on the hammer is 26", just like yours. The drive pully on my jackshaft is 8" and I am using a belt that is 8" wide. The motor is a 10 hp, 1800 rpm single phase unit. I haven't had any problems with my set up, though I've never checked it with an ampmeter while it was running. As far as rpm of the hammer is concerned, you should be able to run that hammer at 225 without any problems. I run my around 200 and I've seen another large Bradley set up to run quite a bit faster than that. Somewhere I got the idea that the pulleys mounted on the motors supplied by Bradley were 6" OD but I can't find that reference now. Patrick

Michael, I have a jack shaft on my hammer and it is there just to control speed since I have motor that runs at 1800 rpm. Through a compbination of jack shaft and pulleys I've got the hammer running at about 200 bpm when at full bore. The jack shaft it self does not give you mechanical advantage, i.e. you couldn't get away with using a smaller motor just because you using a jack shaft. Patrick

Decarburization, as Kenzie noted is indeed due to the diffusion of carbon from the surface of steel into the atmosphere surronding the steel. It is a little bit like osmosis, except that the carbon doesn't just exist as carbon but will subsequently combine with oxygen in the atmosphere to form carbon monoxide and carbon dioxide. Since the movement of carbon within the steel happens by diffusion, the temperature will control the rate at which carbon leaves the steel surface. Time at temperature will control the depth of decarburization. In large forgings, most of the decarburization occurs during the forging step since that stage has the highest temperatures. Some additional decarb will occur during heat treatment if that operation is performed in an oxygen rich envirionment. On our forgings we expect to have 1/8-3/16 inch of totatl decarb after heat treat, assuming no machining prior to heat treat. The hardness results reported by Downfish would suggest that his anvil experienced only minimal decarburization. Since decarburization is driven by the desire for carbon to combine with an element it is more attracted to than iron (generally oxygen) decarb can be prevented by heating in an atmosphere that is already carbon rich or absent of oxygen. Alternatively, a physical barrier can be created between the steel surface and the oxygen rich environment. For those curious about my background, I am a plant metallurgist working at the Scot Forge company in Wisconsin. I've been here for the last 6 and a half years and prior to that worked at Timken in the bearing devision for two years. I've been forging myself for about 12 years. Patrick

Guys, Thanks for all the input. The largest piece I heated so far is a 4x4x8 block and I did do the 3x6x5.5 billet i mentioned before. More often what I am doing is forging either a bunch of short sections, for expample 1" diameter x 4" long for tongs, but maybe having 10 of these in the forge at once, or bigger chunks for hardy or power hammer tooling. I get most of my raw material from work as scrap, so it is not unusuall for me to have odd shaped blocks that need to be forged into more useful sizes. I recently started a project in which I used two pieces of 2.25" round, 20" long each. With my current set up, I was able to heat both of these at the same time, then draw them out to 66". I was able to bend a nine inch diameter circle in these. Once I had the piece bent roughly 180 degrees, I was able to get it back in the forge and re-heat it to complete the bend. I've also done some forging of heavy plate (1.5-2" thick) x 4x6 for bases for some sculptures. I can definitly see myself doing more work like this since I really liked the way those pieces turned out. As you can see, my work varies enough that it is not easy to pick a single size to design around. I really don't do much welding, so I am not concerned about flux eating up the refractory. My primary problems are abrasion and cracking of the refractory materials. I have had very good success with a floor made from a layer of soft firebrick covered in hard brick. For a number of years I've used a ceiling much like the one Jim F. describes-Kaowool blanket compressed into a steel shell. That does work well. The biggest problem I've had is with the bricks I'm using for the walls cracking. Apparently they don't handle thermal shock very well. Another friend of mine with a similar brick pile forge has his forge lined with Kaowool board to shield the bricks from direct contact with the flame from the burners. He has found that to work very well and doesn't have the cracking problems I've encountered. To answer Micheal's question about rates on the Scot Forge presses: I don't know what they charge for the NAF press. A couple years ago Tom Joyce spent some time one two of our smaller presses in the Spring Grove, Il shop. I heard that he was charged $20 per minute, but I have not verified that number with our sales staff. I expect it is pretty accurate though.

Monstermetal, I checked out the Pine Ridge site. That is a very interesting burner option. How have you found that burner to perform in the lower temperature range? I do a lot of work with Mokume, but in fairly big sections, so I need to have good temp control in the range of 1400-1600 F. For steel I often forge in the 2300+ Range. My current burners are very simple-just a piece of 2" pipe with several smaller diameter pipe sections nested inside that to serve as a flame holder. I am able to get a pretty wide range of temperature with these burners. Last year I did a forge weld of six pieces of wrought iron bar (1x3x5.5) using these burners and we had no problems getting the whole billet up to a dripping heat. I don't normally run the forge that hot, but it is a nice feature for some projects. How is the ribbon burner with respect to oxidation? My burners do tend to generate quite bit of scale, which isn't usually a problem, but I have had several people comment on the difference in scaling between gas and coal forges. Patrick

Danger Dillon and others with large hammers doing large work: Would you mind describing the gas forges you use for work you are forging under the Niles, Bradley, or other large hammers? I will be building a new gas forge next year and have some ideas in mind, but I'd like to hear from other people doing large work. I am currently using a "brick pile" type of forge with two side mounted burners. These are run on forced air and propane. I don't have any problem getting the heat I want, but I am finding that the bricks don't take the thermal shock of start up and cool down very well. I have also used Kaowool lined forges and that worked OK, but eventually the steel shell oxided around the openings and I had to replace it. My current idea is to build something like an oversize Mankel horeshoeing forge-one that is open on 3 sides. I intend to close of one side with a removable wall so I can get large flat work when needed. The front and back would have smaller openings for drawing long straight work or accessing smaller pieces. My current forge design has a 14" x 24" x 6" interior and I find that I do use all of this volume for some jobs, especially when I have lots of peices to heat at once, so I would like to keep the forge around this size. I am not too concerned with gas consumption, since, at this size, you are going to burn a lot of gas. My current design burns a couple of gallons an hour when running full bore, but that is still relatively low cost. Your input is appreciated. Patrick

I've tried to torch H13 in the past and I was not able to do it. If you can get it to work, then you'll want to grind the torch cut surface clean an flat before you forge. If you don't, the little laps and cracks that form becasue of the rough surface can propigate during cooling wreck whatever it is you've made. I've seen this happen with my own work and now I takes steps to prevent those laps from happening up front. Patrick

Ernie Limkueler (I know I spell his last name wrong) wrote an article several years ago on rec.crafts.metalworking in which he details the fabrication of an anvil from plate. He uses Rankin wire to hard face the entire thing. I have used a Ranking stick rod to repair two anvils. It does NOT color match and it does stress crack as it cools. I called the folks at Rankin to see if that cracking was normal or not and they said that it is. In the future, I would personally avoid the Rankin products unless I was sure they would NOT stress crack. What I am looking at now for anvil work is rod and wire made by Cormet. We use their F40 FC-G to repair and reface steam hammer dies. This alloy is a little on the soft side for an anvil, but still quite a bit harder than 7018. Patrick

I have forged lots of H13. It is pretty forgiving, but fairly stiff, so large section sizes will require a power hammer. Forge in the lemon yellow range down to orange. Do not quench **EVER**. Air cool or slow cool. If you get any laps or cracks during forging, grind them out while the steel is hot, otherwise they could propigate during cooling. H13 is a great tooling material and of the tool steels commonly used, relatively easy to forge and heat treat. Patrick

John, Look online for a used copy. You'll probably save yourself at least $100. Patrick

Kenzie, Welcome-It is good to have another metallurgist on the board. I am a plant metallurgist for Scot Forge, so tend to work with very large sections and a 50,000 gallon quench tank, but the principles are the same at the small scale. There are a couple of other metallurgists floating around the blacksmiithing community, all with slight variations in experience and background. It provides a very nice blend of technical resources for the folks who are trying to work out forge and heat treat problems on a relatively small scale without a formal metallurgy background. Patrick

Normalizing is often best viewed as an "air" quenched. It is typically performed by austenitizing, then cooling in air, either still air or forced air depending on the grade and desired hardness. 4340 is not going to form martensite during this process, but it does have the advantage of refining grain size and producing a fairly uniform (or "normal") microstructure. After forging, prior to any heat treatment, it is common for grains to be large and for there to be a mix of phases/microstructures present in the forgings, especially if it has a variety of cross sections. Normalizing gets you to a uniform starting point for the next heat treating step, which typically is austeniting and quenching for the purpose of forming martensite or bainite. So to answer Grant's question, yes, a normalized condition is often the preferred condition if subsequent heat treatment is required. In the specific case John brings up, the pieces will be welded. Now, welding can be done successfully on this grade provided the proper pre and post heats are used. As longs as these temperatures don't exceed the tempering temperature, you can weld without significantly altertering the properties develped during heat treatment. In the case of these chippers, the service environment sounds like it is pretty hot so failure is likely going to be do to softening over time and then wear or abrasion of the blade. A quench and temper will probably give a longer service life than a norm and temper, but there may be other factors influencing this that we don't know about. John- If you are doing a lot of tool making, a copy of the ASM heat treaters guide would be a good investment since it does give a lot of charts and graphs showning hardness vs tempering temperature for hundreds of grades, including 4340, 4140 and the other tooling grades. Patrick

What size stock are you using for these pieces? Also- How is the Bradley running? How would you compare it to the Niles? Patrick

Ed, 1/8" per foot taper on the keys is what is in my Bradley and this is also the angle on the keys in our steam hammers. If I had to guess I'd go with the 1/8" per foot for your machine too. Patrick

I don't thin the honey at all. I just squirt it out of the bottle onto the drive wheel of the hammer and let the belt spread it around. If you can dribble it down into the region where the belt and wheel meet that works well. I've used this technique on my Bradley and on a flat belt driven drill press and the v-belt on my lathe. I have been doing this for at least a year and haven't had a problem with insects. Patrick

Michael, You can contact Clifton directly and buy them from him. Price is around $200 US, but they are 10 hours long and worth every bit. I am not aware of anyone else who sells that set. UMBA does have about 30 hours of Clifton doing public demos over the years and he covers everything in those videos that he deoes in the set, but the information is not organized as well and the shots are not always as good since the cameras were quite bit further away. There are a few things covered in the public demos that don't show up in the set Clifton sells, but not much. Personally, I have all of the videos I could get my hands on of Clifton working because there just isn't anyone else out there (besides Steve Parker) showing the methods Clifton uses. I am only aware of one or two videos of Steve working, and in one of those he's working with Clifton. If you 're a power hammer user and you want to get the most out of your machine, get all the material of Clifton and Steve that you can. You will not be disapointed. Patrick

I hosted a tong making workshop over the weekend and one of the attendees brought along the induction heater Grant sells. What a sweet machine. 30 seconds or less to heat 1 inch round. You could get spot heats exactly where you wanted for localized bending or thinning. It was a really handy tool to have for this type of work. Patrick

If you're belt is slipping too much, belt dressing can be used to improve things. Normally, you don't want a hammer cluthch to be too grabby because that can make it difficult to control. On the other hand, sometimes you don't get all the speed or power out of the hammer becasue the belt is just a tiny bit too loose. This is when belt dressing can be helpful. The best belt dressing I've used, both for splip belt clutches and regular flat belt (and even V-belt) drives is plain old honey.

You're right. The force necessary to upset the mass needed to create a swage is subtantially more the the force applied to the tool in use. Unless you have al arge anvil wth a thick heel, it is safer to perform this type of upsetting in a seperate block designed for that type of work. Such a block could be fabricated and then set over the middle of the anvil rather than the heel and it would work fine.

The really important thing is not whether you use tongs or a bar. The important thing is to hold the work so it doesn't escape when you're forging it. I use both methods, though most of the time I am set up to use tongs. What I will do is weld a short bar to larger stock to serve as a tong hold. For example, Sunday afternoon I forged a 4x4x8 block into a sqaure taper for a square horn to replace the heel of an anvil that broke off. I welded a piece of 1" round to the end of the block since I don't have tongs for 4" square. It worked beautifully. Patrick

John, I am located in Beloit WI and just this summer bought 4 tons of steel in a variety of sizes. Most of it is 1018 and a lot of it is pretty large if you don't have a power hammer, but I do have a quantity of 3/4 round. I also have 4140 in 1 11/16" round that would be a good size for hammer/ handled tools and anvil tools. You can contact me through this site or feel free to send me an email directly: pnowak@scotforge.com. I am planning to be at the Centau event on Nov 14 and the week after that, Nov 21 I am hosting a tong making workshop at my place. Hope to see you there. Patrick

In industry there are still some steam hammer run on steam. Up until about 2 years ago we had 6 ranging in size from 4000-8000 lbs rams running off of a couple of very large boilers. These have since been converted to running off of compressed air because it is more cost effective to do so. Patrick

Sulfur certainly will make steel hot short as will and excess of copper or lead. Sulfer and lead are both sometimes added to improve machinability, though lead is not as widely used any more for environmental reasons. Steel with several % of surlfer, such as 1117 or 1144 is still quite forgable though. I had a somewhat similar condition occur recently when forging H13. In my case, I had previoiusly overheated and melted some copper in the forge. The H13 was sitting in the pool of liquid copper and I think that some of that copper wicked up along grainboundries on the surface of the H13. This weakend the grain boundaries and allowed tearing to occur. As far has having a chunck of Aluminum or a bearing in a bar and that causing problems-this is very, very unlikely due to the way steel is produced. Aluminum has such a low melting point that if it were in the scrap metal, it would melt and be absorbed into the liquid steel like any other element. The same thing would happend to a bearing. Even if the bearing didn't melt, the original heat treatment would be completely undone. This is not to say you can't have hard spots in steel, because you certainly can. But they are much more likely to be the result of non-uniform cooling at the mill than to imcoplete melting and homoginization of the the raw materials. Patrick

Grant/Ironstein, I would agree that most of the time high speed steel is not a great choice for hot work tooling, but remember that I qualified my recommendation with a specific hardness -50 HRc. Even 4340 will get that hard and that is a typical hardness for anvil faces, hammers and hammer dies. In the tool I made, I intentially tempered to a hardness SOFTER than it would normally be used at since I wanted to pound on it. I also radiused the striking end. The reason I suggested this grade over H13 is that in some cases, such as the long, fairly narrow hole described earlier, H13 will get hot enough to bend in the work. Certainly bending is preferable to catastrophic, uncontrolled failure, but in the right applications I think that high alloy steels could safely be used. When you suggested press forging I envisioned a process in with the punch is pushed in mechanially or hydrallically. In such an arrangment, the dimensions of the dies would be set to prevent bottoming out a tool and you wouldn't have the impact loading associated with hammer forging. As you know, service failures are not all material related, but can also be related to tooling design, including hardness. Patrick

Vascowear was made by Teledyne Vasco, but I believe they are no longer in buisness. I think a similar product is avialable from Carpenter Steel. If you do a google search for Vascowear you should find it. You probably could also use any of the commonly available high speed steels such as M2 or M42. Just make sure you get your tooling properly heat treated. I was aiming for a hardness of 50 HRC with my punch. This gives a good balance of hardness and resistance to deformation at high temps. Depeding on your needs you could temper higher for increased temperature reisitance. Make sure you DON'T heat treat too hard. The normal hardness range for these grades is pushing or exceeding 60 HRc and that is just too hard and brittle for forge tooling. Patrick