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I Forge Iron


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    Larimer County, Colorado, USA
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  1. I got a drill press vise that didn't have a handle. So I proped a piece of round steel up where it was in a propane torch flame, and after twenty minutes or so got it hot enough to upset the end, put it throught the vise nut, and did the other end. It took a couple of hours, but I still use the vise all the time. I heated metal with a crab boiler for a while. I had to wait years for the internet to get better pictures, but finally got around to building some different forges, and got an old Vulcan anvil, and enjoy making a little money from a fun hobby.
  2. Boris, This isn't really directly related to your forge question, more towards your comment about steering your son towards microcontrollers. I acutally built a couple of microcontroller based projects that are related to blacksmith work. My electric kiln is Arduino controlled: it interfaces a thermocouple with a decoder IC, drives a little relay that in turn drives the 220v contactor for the coils, and has a plain text interface over the usb com port for programming ramps and soak times. I mostly use it for annealing glass, but I'm wanting to heat treat stainless, and based on some pointers from folks on this site, it should work for that without modification. The same control system would work for a heat treating salt bath, or maybe to control the temp on an electric start forge. My pneumatic power hammer is running an Arduino as well. The analog inputs on the Arudino allow pots to be used as a cheap way to control the stroke length and bias the hammer stroke to the anvil end. I put a switch to go between recipocating and a single shot for striking tooling. The microcontroller runs a shuttle valve that, once again, folks on here helped me understand. I volunteer as a science fair judge, and have seen early high-school level kids turn engineering knowledge of similar interest into winning projects. Metal casting, and stove building both wound up at the regional and state level. While it is a primitive art at it's core, there is plenty of material science, industrial engineering, metallurgy, and physics that can be applied to blacksmithing. I think Beagle Bone might be better, but If you ever want Arduino code, circuits, or advice, I would be glad to share. - James B
  3. Frosty, thanks for the search tip (passivization), I'll check that out. I might be able to convert one of my plating tanks for an electro polish. I've done the electrolysis rust removal thing, and have an even better constant current power supply now. And Rich, I've been pretty successful making edged tools with tool steels, and forged stainless, just never tried polished or edged stainless. I scratch built and programmed a controller for an atmospheric digital kiln. I use it for tempering borosilicate glass (which shatters if you do it wrong), so I can dial in ramps and soaks with good precision and accuracy. More interested in what the forging does or doesn't do to stainless, but Frosty's search suggestion got that answered. thanks fellas [edit] I found a couple of good descriptions of passivation: http://www.mmsonline.com/articles/how-to-passivate-stainless-steel-parts http://www.delstar.com/passivating.html and some formulae with temp/voltage/current for electropolish on different types of stainless: http://www.fischione.com/product_support/model_110_application_notes.asp Looks like a good cleaning and some quality time in citric acid is a good place to start for a corrosion resistant finish. I didn't realize the corrosion resistance was a surface film. I have a couple temp controlled plating baths with fume extraction that I might use for an electropolish tank. I guess I'll have to do the final sharpening after it comes out, since that whole point charge collection thing will erode a sharpened edge along with any metal contaminants. I'll go practice drawing out a taper now, do you hold the metal end of the hammer, or the wood end? :-)
  4. Wasn't quite sure what forum this fits in, but it is mostly related to how heat and pressure change metal, so here you go: If I heat stainless up to an orange heat in the forge a few times, and hammer on it, does that wreck whatever they alloy in for the corrosion resistance? I would guess that it depends on the type of stainless. So if it does, is there a type of stainless that is particularly good for this? I want to make some hand forged cutlerly. thanks James B www.hotworksgallery.com
  5. Duralite sells some wire for pinning electric heating elements to fire brick, supposed to be good to 2500F. I've used the product in my electric oven, but not the forge. I like the rigid ceramic fiber board for overhead insulation, or wrap the kaowool in a circle and slather a mix of Kaolin and Pyrax to stabilize, then ITC-100 on top of that. But if you want to wire it up, Duralite is really good to deal with. http://www.duralite.com/store/scripts/prodView.asp?idproduct=110 James Brauer www.hotworksgallery.com
  6. I put a cast iron pipe reducer over a turkey fryer burner, made a litle basket out of expanded metal, and put the lid from a dutch oven on top. It heated metal hot enough to hammer, but it took a while, and the expanded metal burned out pretty quick. I've built several propane burners since then, and there is no comparison. You will waste enough propane to cover the cost of some plumbing parts for a burner pretty quick. If you are setup to weld, I doubt you will find making a burner all that difficult.
  7. This thing is hammering metal to my satisfaction now. Based on Mac's advice, I swapped out the existing cylinder with a smaller cylinder with a longer stroke. Then I tightened up the bottom die, have the hammer sliding on a linear rails and bearings, and re-wrote my firmware. I was able to pound out a foot for a traditional woodworking holdfast in one heat on 3/4 mild steel, and two heats with stainless. I'm not positive, but I swapped the supply and exhaust on my valve and it seemed to hit harder. I wonder if those spools flow better in one direction than the other. And I think I am still somewhat limited by the exhaust strokes. When I dial a full stroke, it doesn't hit as hard as a 1/2 stroke. I think the exhaust is building up in the hose between the cyl and valve, and anything longer than 1/2 stroke has to to start pushing through the spool. Floyd recommended a quick exhaust valve (thanks), and I may install one. But for now, I need to spend some time hammering metal and grinding on my dies. Thanks for all the advice. I'll try to post a detailed write-up with clear photos of the build, and explain how I built the electronic controller for either dialing in reciprocating stroke lenght, or setting the foot switch as a single trip.
  8. Rusty, you might like the Curvemaker plugin for Google Sketchup. I haven't looked at the code, but suspect they use recursive functions to create series like the Fibonacci. Then they modify some of the coefficients to let you create all sorts of other spirals. I used the tools to create 3D models for CNC routing wood. For metal it is a quick way to study proportions and visually experiment with spirals. I've cold bent some spirals, but just don't have much occasion to hammer them out. Getting a fair curve in hot metal isn't an easy thing to do.
  9. When I was about 9, I figured out that if you spun the little hobby motor backwards, it would light a little bulb. Nobody could explain to my satisfaction why, if you attached two motor shafts and wired them together, they wouldn't perpetually spin on their own. I tried and tried to attach the shafts with scotch tape, but never got it working. Experiences like this are why I volunteer to judge science fairs now.
  10. I use 7/8" disks for artowork bases, though I'm just using low carbon hot-rolled. Almost seems like a waste to use a quality material on something that just needs to be heavy. Welding those end to end would make an awesome anvil for a power hammer.
  11. So this is second hand info from my buddy that used to work for a railroad, but I seem to recall him telling me about a piece of rolling equipment that pulls spikes. Besides that, I searched around, and I think there is something called a 'claw bar' or a 'heel claw bar' that will pull spikes (http://en.wikipedia.org/wiki/Gandy_dancer) but I don't have any idea where to get one. You might be able to forge one, using the photo in the link as a guide.
  12. Mac, that is a horrible photo so it is hard to tell, but the ram guide is pretty stout, and mostly 1/4". But I'm going to rebuild it when I cut the cylinder off of there. It is stout, but has too much slop for my liking, which I can adjust out, but then it binds. I found some linear bearings in a box this week so I might try to rebuild it with those, or I have a couple scraps of that slippy white UHMW plastic I might use. But that leads me to another question, since I'm attaching a new ram: What is the best way to attach the hammer to the piston rod on the cylinder? My hammer shaft is solid square stock, and the first try at this I welded a carefully aligned nut, the same thread as the rod, to the end of the hammer shaft, then locked them together. Would I be better off with something like a clevis, and let the ram guide keep things aligned? Or I was thinking of making two small square plates with a welded nut: one that screws on the piston rod, and one welded onto the hammer shaft. This way I bolt the corners of the plate together, and shim between the plates if the alignment is off.
  13. Now Mac/Frosty, I don't mean to be critical of you efforts to help me, but isnt' the volume of a cylinder the area of the piston times the stroke length? 118 cubic inches for a 5" cyl with 6" stoke less 2/3 of that size is pretty darn close (40 ) to the 38 cubic inch volume of a 2" cyl with a 12" stroke. And I learned the hard way, the part about using oversized air lines. I plumbed 3/4" copper down to my wood shop, and the long length of pipe acts like a small air tank: for anything without a regulator on the end, the first air is really high pressure, then you have to wait for the compressor to fill the line back up to get a consistent output. I actually got a new 2" cyl with a 12" stroke today, so hopefully I can get it pounding harder. After reading ptree's comments, I'm pretty sure there was too much back pressure on the exhaust coming through the valve. I couldn't find the Cv for the valve, but I did see how it effects the reduced volume of air that can go past the spool as the pressure goes up. And this cyl/valve combo was trying to move a large volume of air at 130 psi. If the new cylinder is still choking with this same valve, I might look at leaving the down stroke port open, and using a spring to return, or try a fast exhaust port. I never knew such a thing existed. Everything in the system (ports, barbs, fittings) is at least 1/2", but I did have a pretty good 20ft run of 1/2" hose. My new 2" cylinder has 1/4" ports, so hopefully air supply and exhaust won't be a limiting factor. And my anvil is about 200 lbs if you count the die and top plates. More would be better, but I'm hoping that this will get me by. Anyway, thanks of all the good advice so far. I'll post an update when I get the new cylinder put in.
  14. Thanks for the input. The CFM requirements for that chambersburg is really good info. If I reduce my cylinder volume by about 2/3s, with a 2" cyl, I'll get closer to the air:volume ratio of a store-bought hammer, and hopefully to be able to up the airflow and move faster. I didn' t really know what that ratio was till reading this. It seems like the first stroke hits harder, so the notion of cycling without doing much work makes good sense. After I get a new cyl installed, I might look at how much room I have to add mass. I got that 5" fatty for $10 bucks, but maybe it wasn't such a good deal for what I am trying to do. And the digital controller is similar to a PLC. It reads two potentiomenters, and uses the numbers control the on/off time for the pilot valve. The one pot controls the stroke length, and the other pot is a fine adjustment to make the down stroke a couple hundred micro-seconds longer than the up cycle, so the shortened stroke keeps the hamer striking the anvil, not oscillitaing the hammer in the air at the top of the stroke. It is switching a Mac 4-way valve on and off with a single signal. - James B
  15. I've been collecting parts since 2009, and finally got around to welding up a new air hammer. The anvil is two 2"x3" solid rectangles welded in a T, with 6"x6"x1" plates holding hand ground tool steel dies. The hammer portion weighs in at around 25 lbs. I'm running a Mac 4-way valve with 24v dc pilot that I coded and wired to an Arduino microcontroller to get a variable stroke length with a knob, then a foot switch to start hammering. The air cylinder is a 5" bore x 6" stroke run to my 5hp two-stage air compressor with some 1/2" hose and fittings straight off the tank. I'm spec'ing all this out, cuz it doesn't work all that well, and I could use some advice from somebody who has built one that works. I hook it all up, and it makes lots of noise, but doesn't do much damage to an orange heat 3/8" rod. It sort of flattens it, but in one heat I can do more work with a hammer than this machine. To troubleshoot, I want to try hand hammering on the anvil, but I suspect that isn't the problem. I think I need a longer cylinder, or maybe more mass on the hammer head. I've seen longer cylinders in most of the photos I used as a reference, but I don't get the difference a longer one would make. It seems like anything over about a 2" stroke, and this thing is hitting as hard as it is going to. - James B
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