freemab

Are you telling me that in all that STUFF you have out back, you DON'T have a Bessemer converter lying around? You could just make your own low-C iron ...

Jason, I can't really get any idea of what your design is. Is that "splinterforge" youtube video yours or what? That video shows the Grasshopper Treadle Hammer linkage, except for inverting the (stationary) frame. And I don't mean approximately -- that is EXACTLY the Grasshopper TH mechanizm. Don't let that bother you -- it's not patented and you're free to use it. However, if that's the linkage your using, you're reinventing the wheel. I solved all the problems of that design already. My version is fully adjustable and has a weightless ram. Since I never went around hosting treadlehammer workshops the way Clay Spencer has done with his designs, there are relatively few Grasshoppers out there, but they exist. Here's one: http://macramedia.net/art/tools/hammer/ I have a website that shows a line drawing, but it's not up to date. I am no longer selling the plans, as it was not economically feasible. BTW, I don't know why Frosty keeps calling this a "watts linkage." It's nothing like a watts linkage. It is a doubled grasshopper linkage.

Grant, Have we met? Your name's familiar but I'm not placing you. I have to take umbrage to your comment. Believe me, if the Grasshopper had required "a lot of precision work", the prototype would never have got built. One unskilled builder built a Grasshopper in 40 hours, with a little help from an experienced worker. That would hardly constitute "a lot of precision work." Also, I have no idea where you got the idea the Grasshopper was "pretty floppy." Have you EVER SEEN a Grasshopper, much less tried it out? The prototype gets sloppy (not floppy) only when a part comes loose, and all those problems were fixed in the version shown in the published plans. Really, it's insulting to have one's treadle hammer criticized by somebody who has apparently never even seen the machine. Bruce Freeman BTW, I no longer have any economic incentive here, as I no longer sell the plans. (P.S. -- Gee! What fussy software this is! It wouldn't let me post first try because quotation marks weren't paired!) Quothe: Grant Sarver "..., the distinctive thing about a "Grasshopper" hammer is that it is not guided, it use a 'straight-line' linkage to give a vertical travel. They look really cool on paper, but require a lot of precision work and still are pretty floppy due to the large number of joints in the linkage."

Well, I am a little late coming into this discussion, but I will contribute my 2 cents anyway. I am one of the ones who advocates the use of "cold" water to "warm" a propane cylinder. Obviously, if the water is so cold that the vapor pressure of the propane isn't sufficient for the burner, you could have a problem (but see below). On the other hand, if it's too warm (i.e., hot) you WILL have a problem. So what goes? And what is safe? First of all, a disclaimer: I'm a chemist. I'm not an expert in propane, propane safety, hydrocarbons, fuels, burners, or anything of the sort. However, I have worked with this stuff myself, more than some of you, less than others, and I am able to parlay what I know into advice that can be safe and useful. Enough on me. When I advocated the use of cold water it was specifically to avoid some yahoo from misinterpreting "warm" to mean "boiling hot", dumping his propane cylinder into a tub of boiling water, blowing out the safety plug, resulting in propane filling his shop and igniting on the first flame or spark it encountered. What I know that some don't appreciate is (first) that if the water is of sufficient volume, it's heat capacity will compensate to a degree for a "low" temperature, and (second) that the temperature of the water should not be an issue. Take #2 first: When your water freezes around the cylinder, the pressure inside the propane cylinder is still 50 psi. You need at most 20 psi at your burner and at most 20 psi pressure drop across your regulator. Hence you will not have a problem with water temperature short of freezing the water. Now #1: As you evaporate propane in the cylinder, it absorbs heat and cools the propane. When the propane cools below the temperature of the water, heat will begin to be transferred through the cylinder wall into the propane. Hence, further tapping of propane will further cool the water. But the heat capacity of water is high, so this is not particularly a problem. If your water freezes, you should continue to get propane at 50psi until the layer of ice insulates the tank from the water. Okay, but in practice we do see a reduction in propane flow. What of this? Well, first make sure you're addressing the right problem. If the freezing is occurring in your regulator or in a valve, warming the propane is not the answer. Fortunately, it is not particularly dangerous to warm a valve, and even a regulator can be warmed gently. Warm air is appropriate for this. Do not get these devices hot to the touch -- the plastic components inside could fail catastrophically. Now as to the suggestion of directly warming the tank with warm air. Even that is not necessarily a problem. Suppose we decide to live carefully. You can measure the temperature change of the water around your cylinder over a measured time period, and, knowing the weight of water, calculate approximately how much energy was used per unit time, which is power. Now compare this to the electrical power used by the warm-air blower. If expressed in the same units, then as long as the electrical power approximates the power consumed evaporating the propane, you're okay. In fact, there will be considerable inefficiencies of heat transfer, so these numbers do not have to match anywhere near exactly. But if you're applying many times more electrical power (heat) than the propane is absorbing to evaporate, then you're likely to be heating the propane, which can be dangerous. Those with a background in physics can vet my statements above. No offense taken for corrections to errors.

Grant, You are correct that the Grasshopper Treadle Hammer uses a straight-line linkage, avoiding the use roller or slider guides. However, I beg to differ on your other points. The Grasshopper does not require "a lot" of precision work, and is not the least bit "floppy". There is no part that requires any operation more precise than a drill press. Certain alignments must be done with care, but "precision" scarecely applies. I invite you or anyone else to Marshall's shop (see http://njba.abana-chapter.com/ "open forge") to check out the prototype Grasshopper. (Right now, the lateral positioning of the head of the prototype is not up to snuff due to a problem with collars coming loose. The final version Grasshopper does not use collars for this function, however.) Bruce NJ

Grant - I'm no expert on the subject, but I did a little reading on it a year or two back. It seems that certain materials, notably including cast iron, provide exceptional vibration damping. This, for example, is why a cast iron anvil doesn't ring. Cast iron is not the only material with this property, but it probably is the heaviest, cheapest material, which is why it is used in so many machines. Steel and aluminum, even though strong, just don't compare. Looking further into this, it seems that it is the inhomogeneity of the cast iron that is responsible for the vibration damping. Essentially, the stuff just can't pass vibrations because of all the solid-solid interfaces within it. Cement is likewise vibration damping, but generally too brittle for use as a machine frame. I wondered whether stressed concrete might be usable for machines, but the limited research I did on the subject suggested it was not in the same league as cast iron. Fact of the matter, is that possibly the best simulation of cast iron would be a bolted assembly of steel plates. It would have the same heft, and if constructed properly would damp vibrations fairly well. This only makes sense, however, if steel plates and fabrication would cost less than casting an iron machine frame. And that I doubt. Bruce NJ

I'd be very interested in your work with the Roberts linkage, as this was a linkage I have also considered employing. Bruce

It's an interesting concept, but shouldn't you call this a "power hammer", not a "treadle hammer"?

I think Charlotte has the right idea - an aerosol of chemicals is probably what got to you. But I doubt that was just the vinegar, as vinegar fumes and aerosol aren't that much different. I suspect what you got a snootful of was an aerosol of zinc acetate. That wouldn't be volatile, but you can make an aerosol of anything. And zinc fumes are a known hazard. I've encountered such things myself. While cleaning iron in vinegar, I get a rather pungent "iron" smell from the mix. It takes a lot more iron to harm you than it does zinc, so this is only an annoyance. (BTW, an overdose of iron can be injurious. No need to panic, just be aware.) More to the point, when soapmaking one dissolves lye in water. The best approach is to work by weight and use ice for about half the water. Otherwise, (I surmise) an aerosol of lye forms above the hot mixture - very irritating to the nose. For future reference, it sounds like you sidestepped a REAL hazard when that bag broke. Whenever you put zinc or other metals in acid, the gas that bubbles off is hydrogen. Hydrogen-air mixtures, like acetylene-air mixtures, explode (not just burn) over a very wide range of concentrations. Unlike acetylene, however, hydrogen diffuses very rapidly through air, so if not contained, you're not too likely to reach the lower explosive limit while pickling metal in acid. Do your pickling outside or in an actively ventilated room in the future. Muriatic acid can be diluted a lot and still be much more effective than vinegar for the simple reason that it's a stronger acid. Vinegar is 5% acetic acid, so you could do a seven-fold dilution of your muriatic acid and have the same acid strength at a much lower pH - hence faster reaction. And, as Charlotte mentioned, muriatic fumes will rust anything, quickly. Keep it away from fine tools. I doubt that HCl can actually penetrate the plastic container, but is surely can get by a poor seal. Bruce NJ

It's nice to hear ABANA is improving. I attended one conference - Ashville 1998 (?) and wasn't seriously considering attending another till the recent NY conference - that ABANA canceled. (NorthEast Blacksmiths ran a conference anyway and I attended, as did John Larson.) I find myself highly swayed by John's posting, very inclined to go. But the reason I haven't gone to an ABANA conference since '98 is the cost-to-benefit ratio. If I go to a local meet, I see a demonstrator. Travel costs are low, and there are no other costs to speak of. If I go to a regional meet, travel costs are moderate, there may be an overnight or two, and admission cost is nominal. Sometimes I can make back on tailgating much of what I spend. Maybe I'll have to choose between 2 or 3 demonstrators, but usually such a choice is not too onerous. But with an ABANA conference, too much is packed into too short a time. I can't see all five or eight simultaneous demonstrations. In '98, despite it being a fairly well run conference, I could hardly figure out where I wanted to be when, and missed things I could have seen. I can't watch demos and tailgate. The best I could hope to do is to see a few demos, shop the tailgate sale, and maybe see the gallery. I just cant be in five places at once! I don't have a solution, other than to skip the ABANA conferences and stick to local and regional conferences. Does anyone else have a solution? Bruce