From: jimkirk@news.uwyo.edu (Jim Kirkpatrick) Newsgroups: rec.crafts.metalworking Subject: FAQ part 4 of 7 Date: 1 Sep 94 10:13:36 MDT Organization: University of Wyoming - Laramie, WY This is the FAQ for rec.crafts.metalworking. It is in several pieces to keep the overall size of each part below the limits imposed by some news systems. This is part 4 of 7. Generally, units below are United States dollars, degrees Fahrenheit, and all the other silly backwards units we Americans still use. Sorry. The questions being answered in part 1: 0. Where is this FAQ kept, and where are archives of the newsgroup? 1. The original rec.crafts.metalworking charter. 2. The CLOCKS bitnet mailing list, and other related lists. 3. What are some good books and/or video tapes on metalworking? 4. Who makes good lathes/mills/etc? 5. Where do I buy a machine? 6. What are good magazines to subscribe to? The questions being answered in part 2: 7. Where might one take classes or get instruction? 8. Where can I get raw material for my projects? 9. Where can I get tools, drill bits, etc.? 10. What are some of the related professional/hobby associations? 11. How do I harden/temper metal? 12 How do I wire up this strange motor? 13. How do I deal with mail-order suppliers? 14. How to sharpen knives, chisels, and other tools? 15. Some safety reminders. 16. How do I drill round holes? 17. What's TIG and MIG? The questions being answered in part 3: 18. MIG welding technique. 19. Which MIG welder should I buy? 20. Books on welding. 21. Soldering/brazing topics. 22. What are bolt grades? 23. What is XYZ made of? The questions being answered in part 4: 24. How do I build a furnace or forge? 25. What is Damascus steel? 26. How do I repair/replace this old leather belt? 27. Can I use a drill press as a cheap vertical mill? The questions being answered in part 5: 28. What is involved in building a steam engine? 29. How do I anodize aluminum? 30. Rust! How do I deal with rust? The questions being answered in part 6: 31. Are there any machinery museums? 32. How do I cut metal? 33. What kind of oil should I use on my lathe/mill? The question being answered in part 7: 99. Names and addresses of publishers and suppliers (OK, so I got tired of re-numbering it every time a new question was added!) ------------------------------------------------------------------------------- 24. How do I build a furnace or forge? Geoffrey Keyes posted this on August 26 1993, and it looked good enough to include in the FAQ. JK Ok boys and girls, I'm going to attempt to put together what I know about propane forges/furnaces. This may be somewhat rough since I am doing this extempore. I'll be happy to answer any specific questions people may have. A disclaimer up front. I am not an expert on these beasts and I am not responsible for any injuries, deaths, fires, unexplained explosions, or irate neighbors. The following is what I have tried or seen tried. A little history. I first saw one of these in operation at a North West Blacksmith Association (NWBA) novice class about six years ago. Since then I have built three versions, Mk III is operating just fine today. I hope to be operating, part time at least, officially as Ravens Forge by the first of the year. Gas furnaces are commonly called forges. In fact, a forge is open topped and a furnace is closed. In my opinion an open topped version would lose too much heat to be valuable. The two basic types I've seen have been 1) The brick pile, 2) The pipe or box. Basically, the furnace is a closed space, open at one or both ends, lined with insulation, with an inlet for air and gas to enter. THE BRICK PILE Just what the name suggests, is a pile bricks with a pipe stuffed in one side. The bricks are stacked to provide an open space and the air inlet is inserted into the space. A fan is attached to the end of the pipe and the gas line enters between the fan and the box. The opening is covered by a stack of bricks which can be moved around to provide an opening big enough for whatever stock is being used. Since I haven't mentioned it until now, these bricks are fire or refractory brick. Normal red brick will explode under the thermal stress and even fire brick will break down over time. The first brick pile I saw is still in use. The problems with them are they leak flame and unburned gas though all of the joints and they generally lose too much heat for welding. THE PIPE This is what I am using today. Same basic form, a closed box, insulated, with a pipe for the air and gas to enter. My furnace is a piece of 1/4 steel pipe, 16 in long, with a 1/4 plate welded on the back. About half way down one side a piece of 1 1/2 in pipe is welded to the body. There are two pieces of angle iron welded to the bottom of the case to keep it from rolling over and a shelf welded to the opposite side of the case from the inlet pipe. I use the shelf to preheat steel and to keep my tea cup hot. Attached to the end of the pipe is a fan, in this case an old hair dryer. About midway between the fan and the case there is a hole drilled for the gas inlet. I use two inches of insulation (on which more later) in the case and a pile of fire brick to close up the open end, with just enough space for my stock to enter. The gas source is a 5lb propane bottle. The whole thing sits on the end of 55 gal drum. The air/gas inlet can be as simple as a piece of pipe or a complicated as you like, basically you're going to have to experiment with the size of the outlet end. I put a twisted piece of steel in the end of mine to impart some swirl to the gas as it enters the furnace. This works, but not as well as I would like. Don't push the end of the tube to far into the furnace, since it will just burn off. This is a sort of self correcting problem since if it is too far into the fire it will just disappear over time. I've got a valve on mine, between the fan and the gas inlet. However, my fan is too wimpy for me to use the valve much. The fan is blowing its heart out just keeping up. My next modification will be a burlier fan. INSULATION The insulation used by most of the smiths I know is called KAOWOOL, which is a Johns-Manville product. There is also INSWOOL made by A.P. Green. Both of these are spun ceramic blankets. WARNING The ceramic fibers are fairly friable when the blanket is new and unheated. I suspect that breathing them is a bad idea, so use a filter mask when building your furnace and during the first firing. After that the surface gets hard and crusty and the problem seems to go away. Some smiths I read about have used castable refractory cements to build furnace bodies, but I don't have any direct experience with them. Fire brick, KAOWOOL, and the like can be found under "Refractories" in the yellow pages or try ceramic supply houses. I bought my first KAOWOOL from a ceramic supply. LIGHTING UP This is an exciting process. First insert a burning piece of paper into the fire box, turn on the fan, then turn on the gas. There should be a whump and then a burst of flame. Now adjust the gas so that fire is not streaming out of every crack. Give it enough time for the box to heat up (2-5 min) and off you go. SAFETY Propane is a flammable, heavier than air gas. It will accumulate on the floor until it gets a spark. Then it burns very fast. If enclosed at all it will explode. Check all of your valves and connections frequently. A regulator AND a blowback valve are a good idea. I got most of this info word of mouth and by trying it out myself. However, there are some publications that may be helpful. The summer 1991 Vol 5 Num 3 of Knives Illustrated has a pair of good articles on gas forges. ABANA P.O. Box 1181 Nashville Indiana 47448 This is the largest blacksmiths association in the US and is a source for all kinds of good stuff. In particular they sell plans for a furnace. "A recuperative gas fired forge furnace" Sandia National Labs. I don't know what they charge for these plans anymore. W.L. Goddard 473 Durham Ave. Eugene OR 97404 Wayne writes a column for BLADE magazine and is an ABS Master Smith. He also used to sell a pamphlet of basic bladesmthing info including a section on gas furnaces. I don't know if these are still available. As I said above, I am not an expert and am not responsible for any problems, injuries, or unexplained fires that might result from any of the above info. On the other hand, I have used a furnace described above to forge and heat treat approximately a dozen knives with good results and no injuries or other accidents. If there are questions or if things are not clear (almost a certainty) please feel free to contact me at keyes@monitor.wa.com Good forging Geoff Keyes Ravens Forge ---------------------------------------------- Another recommended book is "The Complete Bladesmith" subtitled "Forging Your Way to Perfection", by Jim Hrisoulas. ISBN 0-87364-430-1, published by Paladin Press. 25. What is Damascus steel? We often see the question "what is Damascus steel" and the next question, "how do I make it" or "where do I get it". In an attempt to answer this question, I've put together several responses that have shown up in the past. --------------------------- From: johnri@saturn.wwc.edu (RICHARD ALLAN JOHNSON) "Damascus" steel is usually created nowadays when 2 materials with differing carbon content or differing properties such as high and low carbon or high carbon and nickel are forge welded together to form one solid billet. My experience is that in general, Damascus does not stay shaving-sharp as long as straight carbon steel but when it dulls it leaves a microscopic saw edge that will cut flesh like nothing else. --------------------------- From: sfm1@ns1.cc.lehigh.edu (SCOTT F. MASTROIANNI) Simply speaking, Damascus steel is an antiquated term popularly used to describe various pattern welded steels. The term was originally used to describe steel from Damascus which had intricate and subtle patterns in it due to the way the steel was made and wrought -- the pattern was a by-product rather than a set goal. These steels contain alternate layers of differing alloy steels that have been forge welded together into a single laminated billet. Frequently these billets are then twisted or physically manipulated in some other manner and/or rewelded to other similar billets. After this laminate steel has been formed into the final shape for which it had been destined, i.e. a knife, object d'art, etc. it is usually etched with some strong acid solution. The etching process will affect the different alloys in different ways; some will etch deeper, producing a noticeable topography, and some will turn darker. The effect is to produce a pattern in the steel of great contrast and beauty. A Damascus or pattern welded steel blade does not have to be any weaker than single alloy, and frequently it is as good if not better in all properties: edge holding, toughness, cutting ability, sharpenability. It is usual practice to use a high carbon and a low carbon alloy as the constituents of a Damascus blade. This unites the best of both worlds: The high carbon steel grants the blade its cutting ability while the low carbon alloy adds to the toughness and shock resistance. It is not necessary to use low carbon alloys at all. Two high carbon steels with greatly differing trace element profiles can be welded to show patterns. I have even read of 440C stainless being forge welded to tool steel -- this can't be an easy process though. In addition, if the pattern in the blade is complex, and many of the laminations cross perpendicular to the edge of the blade, micro-serrations are formed which add to the cutting ability of a well-made Damascus blade. Wayne Goddard, a Master Bladesmith of the ABA and a colleague of Jim Hrisoulas (whose book I recommend for a much better treatise on this subject than I have given here), has a continuing program of testing the properties and performance of forged blades. He has tested hundreds of blades, and found that well made pattern welded blades cut and hold their edges just as well as single alloy blades. The Damascus blades are usually much tougher than all but the strongest (52100 or 5160) single alloy blades. In addition to _The Complete Bladesmith_, I heartily recommend "The Blade" magazine to anyone interested in the latest developments in Pattern welded steel and knifemaking in general. --------------------------------- Robert Allen, rja@sun.com, wrote: I've had the opportunity to discuss Damascus manufacturing with Jerry Fisk and John Smith, two makers who do excellent Damascus. Let's see if I can remember the basics: "Damascus" as used by most makers today means a layered material made from a mixture of high and low carbon steels. Makers differ the mix according to their pet mixes. A billet of alternating layers is forge welded, then folded and re-folded to the desired number of layers. I've been told that more than 200-300 layers is counter-productive, as at that point you start to get too much carbon migration between the layers and you end up with a homogeneous medium carbon steel. The point of Damascus, I've been told, is that the high carbon component gives up a bit of carbon to the low carbon component. When the blade is hardened, the high carbon component gets fairly tough, which gives you good edge holding, and the low carbon component gets a little harder. The point of all this is that damascus is supposed to have a "micro-serrated" edge, which lasts a long time. The theory as I understand it is that the low carbon component wears faster than the high carbon component, giving you an "aggressive" edge that can't be beat. The two Damascus blades I have seem to bear this out, beyond what merely varying the the grit on a sharpening stone would do. After forging a Damascus blade, it is etched in one of several acid mixtures, which causes the pattern caused by the layering to emerge. Typically damascus is then blued to bring out the contrast between the layers. Damascus is often modified by forming to create specific patterns in the steel. Some makers have produced small American flags in the pattern. Note that such patterns are produced strictly for the sake of art, not for performance. Popular performance oriented patterns are ladder pattern (has ladder "rungs" the length of the blade), San Mai (various makers wrap a carbon steel layer between two damascus layers), random pattern, etc. Some makers claim the different patterns offer different structural or cutting advantages. The patterns are made by machining the billet or blade with the pattern, then re-heating and the material and hammering it flat, etc. There is also cable Damascus which is forge welded cable. Most makers I've spoken with told me their cable Damascus looked good, but wasn't as strong as the other Damascus. Cable Damascus has a unique reptile-scale type pattern. A good Damascus should OUT-perform straight carbon steel in most areas, but particularly in edge holding. Some makers say their Damascus is not as springlike, and so the blades will not spring back as close to true as a carbon steel blade will, under a vise-bending test. I've found that most famous makers are honest about their Damascus. Tim (?) Winkler told me he makes Damascus strictly because it looks nice. Wayne Valakovich (sp?) told me that his normal Damascus isn't as good as his carbon steel, but that his high-density Damascus is better. Fisk and Smith both say their Damascus is better than their carbon steel in most regards, although it still is not as springlike as their high carbon blades. I've cut down small trees with a Fisk Damascus blade, with no apparent wear on the edge. I have a Smith bowie which cuts through blue jeans with zero apparent effort. ------------------- jschmidt@netcom.com suggests that knife blanks may be available from K & G Finishing Supplies, (602) 537-8877. Also everything else you might need to finish a knife. Books that discuss Damascus steel, either historically or how-to: Custom Knifemaking 10 Projects from a Master Craftsman Tim McCreight Stackpole Books 1985 ISBN 0-8117-2175-2 7 1/4" x 9 1/4" 222 pg. paperbound ($14.95, $20.50 in Ca. when I got it) A History of Metallography: The development of ideas on the structure of metals before 1890 by Cyril Stanley Smith 1960 -- The University of Chicago Library of Congress Catalog Number: 60-7243 "DAMASCUS-USA" distributes a catalog. It says on the cover "World leader in hand made forged-to-shape Damascus Cutlery Steel. More of our knives are in use world-wide than anyone else's." It looks like they mostly sell ready-made Damascus knives but there is a page where you can order Damascus Billets (Bar stock) in any size or pattern. This apparently is a one-man operation, by Dr. Robert Charlton 919 482 4992. The book "The Complete Bladesmith" by Jim Hrisoulas has also been recommended. 26. How do I repair/replace this old leather belt? A big problem with some lathes is that the drive belt, or one/some of the belts, are assembled with the lathe and are not meant to be replaced without disassembling the headstock. This is a task that is difficult at best. Older South Bend and others use a flat leather belt, glued or stitched. Newer lathes sometimes use a V-belt in the headstock to transfer power from one set of pulleys to a set of pulleys on the spindle. For V-belts, there is at least one linked replacement. Gates Rubber Company makes "Nu-T-Link" belting that can be cut to length, threaded into position, and joined with special T-pins. The pins might get in the way, depending on the application, so be careful to check out clearances before you buy. (ref: HSM Jan/Feb 1992 pg 6-7). You might look in the yellow pages in your area for bearing/belting or other mechanical suppliers. Flat leather belts sometimes just start slipping well before they break. One suggested fix was to apply "friction tape" to the pulleys, especially if they are polished. It needs occasional replacement, but is cheap and easy. Another fix is to apply some sort of belt dressing; one person suggested contacting New England Belting in Springfield MA. They may also be able to supply a replacement. Also try Hudson Belting in Worcester Massachussets at (508) 756-0090. A non-leather replacement is called Texalon, made by J.E. Roads & Sons, 2100 West 11th street, Wilmington DE 19899 (phone (302) 655-6513). It is sold through Hermance Machine Company, 178 Campbell Street, Williamsport PA 17701, phone (717) 326-9157, and possibly others. (ref: HSM March/April 1993, pg 8-9). Texalon is cut to length, the ends prepared, and then glued. At least for Logan lathes, there is the manufacturer: Logan Actuator Co. 4956 N. Elston Ave Chicago, IL 60630 (312) 736-7500, (312) 736-6854 (FAX) I have also heard of stitching a brass cabinet hinge onto a leather belt, then assembling in place (as long as the hinge pin can be secured from dropping out!). Also, per a post 5/17/94, try Page Belting in Concord, New Hampshire. 27. Can I use a drill press as a cheap vertical mill? Sometimes people want to use a drill press with an X/Y table attached as a cheap vertical mill. Will this work? Generally, yes, but you should not do this. The bearings in a drill press are not designed for side loads. This may cause premature failure of the bearings, and may also cause significant sideways deflection and wandering (if you must do this, don't expect finish-quality cuts). If you extend the spindle down very far towards the work, the deflection could be quite severe. Mill spindles are more stout than drill spindles. In some presses, the chuck is held in only by a taper. Side pressure could cause the chuck to fall out. Some milling tools are not designed to be held by a drill chuck, or if your spindle does have a taper, the taper will be wrong (mills usually use either a Morse or "R" taper while drills often use a Jacobs taper; check this out before buying any tools). An X/Y table often does not come with finely-marked dials, and may in fact be quite inaccurate. For coarse cuts this may be OK. Note too that a real mill will have controlled Z-axis feed, while on a drill press this too will be quite rough to control. As for how big a cut you can make, or how accurate your setup will be, there is no consensus. You'll have to set it up and try it. Considering the bearing/deflection problems, moderately light cuts would be recommended. Speculation: use end mills, not fly cutters (or at least avoid fly cutters, or be careful). Depending on the setup, a cutter may enter the work, then due to the deflection the cutter might be driven into the work farther, jam, and break itself or the work. An end mill cuts more or less continuously and might not have the same problem. Paul Amaranth volunteered his experience: --- I have only machined soft materials (copper, plexiglass and other plastics). I would not recommend using anything but very light cuts (if at all) in anything harder. As you would expect, I had a number of problems. Fine vertical depth adjustments are difficult. I set the quill stop at the desired depth and held it in place by hand. You could move the table up, but most drill presses seem to use a fairly coarse rack and pinion for the table. I used an endmill, which worked fairly well. Any backlash in your x/y table will get you into a load of trouble. This may not be too serious if you're facing off a surface, but will cause lots of problems if you want to make slots or cutouts with any precision. Backlash may also cause chatter. In summary: this works if it's absolutely the only way you can do it, you don't need a lot of precision and you're working with soft materials. I got around these limitations by buying a real mill. --- Alternatives: If you have a lathe, consider buying/making a milling attachment, if your work size and lathe will allow. Consider buying an inexpensive mill/drill machine if you can't quite afford a mill. In general, some of the same comments apply to buying a mill/drill or other combined unit as opposed to a dedicated machine for each purpose. Mill/drill machines are not as rigid for milling as a pure milling machine, but may be the only alternative before the money runs out. Combinations seem to work adequately for many woodworking applications but metalworking generally requires a lot more force.