This information is not intended to be a book, but as I am working in the shop, I sometimes think of things that might be helpful to other blacksmiths - particularly those new to the craft. These tips typically are the result of the processes and tools I have tried. If time permits, I write the thought down and enter it here.
The information contained herein, one way or another, almost always originally came from other blacksmiths. As blacksmithing is so very old, there is not much that is new. Almost every basic method or process has been tried before someplace or sometime. There are about as many ways to blacksmith as there are blacksmiths. Each blacksmith has to process the information he/she receives and try to make it fit their situation.
Please accept these for what they are - mostly the things that work for me. They may or may not work for you:
SOME OF MY THOUGHTS ON BLACKSMITHING:
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See also: Care and Maintenance of Anvils
A shop anvil of 150 pounds or more is usually preferred for a lifetime of blacksmithing. The late Francis Whittaker, a famous USA blacksmith, used a 150 lb. anvil all his life according to George Dixon who wrote "A Blacksmith Craft". A larger anvil can have both advantages and disadvantages. A larger anvil has more mass, doesn't move around or wiggle as much as a smaller anvil. A larger anvil has bigger work surfaces, which can be advantageous for most forgings, but can get in the way of more intricate forgings. A larger anvil usually has bigger and longer horns which extend out and away from the base/stand. That facilitates making big scrolls and bending long forgings.
The sooner in a blacksmith's career he/she can acquire their lifetime anvil, the fewer times he/she will have to make hardy tools. A one inch hardy hole seems to be the most common today. Even though specified as 1 inch, hardy holes can vary a little in size depending on how the hole was made (punched, core box, broached). Punched hardy holes generally taper.
In the older anvils, smaller anvils (80 to 120) pounds generally have smaller hardy holes (3/4 to 7/8 inch). It is easier for the lone and or younger blacksmith without power equipment to make hardy tools for smaller anvils. It is also easier to find the steel used for the hardy tools, as it too can be smaller.
The smaller anvil also usually has smaller round horns which facilitate more intricate forgings.
For safety reasons, many blacksmiths dull the sharp points on shop anvil horns.
A long lasting anvil face depends on several factors: (1) the quality of the face steel (2) the thickness of the face steel (3) the hardness of the face steel (4) the toughness of the underlying anvil body (5) and the care taken by the user.
If an anvil is used that does not have any good square edges (possibly an older anvil), then a square edged block that fits into the hardy hole is useful. Any size will work, but could be as small as 2" X 2" X 1". Mild steel will work in a pinch, but a harder steel will last longer.
Hard anvil faces (HRC 58-65), of sufficient thickness, do not dent easily with the errant hammer blow; nor do they become saddle shaped, nor do they have edges that get pounded down or become rounded. Typically the bigger the anvil, the thicker should be the hardened face and 1/2" should be minimum for any anvil. There are anvils sold today that have a flame hardened face. Flame hardening results in a face hardness of only approx. 3/16" thick.
For economic reasons, all quality anvils made today are cast of various kinds of steel except for the Peddinghaus now owned by The Ridgid Tool Company. The Peddinghaus is a drop forged anvil made from a medium carbon steel C45 (1045). Several well known brands of modern cast anvils are made of cast ductile iron (not steel).
Neither dropped forged anvils nor cast steel anvils have the face grain oriented along the face as did the old anvils with a forge welded rolled steel face plate. Grain orientation can be one component in determining toughness in an anvil face.
Some modern anvils have flame hardened faces and flame hardening is a very shallow (typically less than 1/4") hardening process. The face might be relatively hard HRC54 to HRC56, but with use, the thin face will depress into the anvil body over time especially at the anvil edges.
Older anvils with fire welded face plates sometimes had problems with the face separating from the body of the anvil. When these anvils were the common anvil being sold, there were companies that specialized in forge welding new face plates to the anvils when the face plates came off or broke. Unfortunately, today I do not know of any companies that weld face plates to anvils in the USA. The Ernst Refflinghaus Co. in Germany still does, but it is expensive enough that most blacksmiths buy a new cast steel anvil instead.
Most anvils made in the USA today and Eastern European anvils have a face that is soft at HRC44 to HRC52 and can be easily filed with a file. A few modern anvils have a face hardness of RC 54 to RC 55. I am aware of only 2 anvil manufactures that still make anvils with a face hardness of RC59 or harder. Those are the Ernst Refflinghaus Company of Germany and Vaughans of the UK (New web site doesn't look like Vaughans has maintained the quality of their anvils). Most of the older anvils with forge welded hot rolled steel plates on the face were hard at HRC 58 to HRC 65 and often could not be cut with a file (these anvils are no longer made primarily due to the high cost of labor). That high hardness was desired by blacksmiths. The high hardness was typical unless the anvil was made on Friday afternoon or had been in a shop fire. Today, manufactures say they keep anvils soft for safety reasons which may or may not be true. Generally a soft anvil is the result of keeping the manufacturing cost down. It is more difficult and expensive to make a good quality cast steel anvil with an overall hard face.
One way to determine if an anvil face is of adequate hardness is to test it with a file. Most modern files are HRC 60 to 61. File testing is a comparative test. Testing several steels of known hardness is the best way to estimate hardness. If a file can easily cut into an anvil face, the face is much softer than the file. It the file can not cut into the anvil face, the anvil is as hard or harder than the file.
Another way to test the anvil is to hit the face moderately hard with the peen end of a modern quality hard ball peen hammer. If the hammer makes a dent in the anvil, the anvil will also become dented with normal use. An anvil of RC 59 or harder does not dent with a normal ball peen hammer blow. Keep in mind that hitting an anvil directly with any kind of hammer is not recommended, but it might be useful to test anvil face hardness if safety precautions are taken.
The harder the anvil edge the more susceptible it is to broken/chipped edges, particularly if the hammer is too hard. The quality and kind of the steel used in the anvil face has a lot to do with susceptibility to edge chipping. A few, but not all, cast steel anvils made in the mid to late 1900's have had problems with edge chipping. Most cast steel anvils have no more of a problem with edge chipping than anvils with a hard fire welded face plate. Some anvil makers such as Vaughans (HRC60-65) temper their anvil edges so they are softer than the rest of the face, but most modern anvil makers just make the whole anvil face softer.
Soft anvil edges typically just dent, with the errant hammer blow. Often a damaged soft edge can be hammered back close to it's original shape. Refflinghaus relies on their tough steel to help keep edges from chipping.
When purchasing a new anvil, about the only way to determine how susceptible the edges are to chipping is to look at the anvils in use and or talk to purchasers of those anvil.
Today, there are low cost cast iron (not steel) anvils being made, which are much too soft and break too easily for general blacksmith use, but might be OK on a bench or in a shop that is not a blacksmith shop.
Today, several well known anvil manufacturers are making their anvils out of ductile cast iron, rather than cast steel. Unlike grey cast iron, ductile cast iron has proven to be a satisfactory anvil material as it can be as hard as many cast steel anvils. If there is a downside, it is that they are not as tough as the typical cast steel anvil. Nevertheless, they can be a serviceable anvil particularly if care is taken. If the manufacturer of the anvil does not specify that their anvils are made of steel, there is a good chance they are made of ductile cast iron. At least one major anvil manufacturer sells ductile cast iron anvils and calls their anvils steel anvils.
When manufactures heat treat a steel anvil it is difficult to overcome the tendency for the greater mass in the center of the anvil face to cool slower, in the quench, than the rest of the anvil. When the center cools slower, the result is steel that is softer in the center of the face. Also the smaller the anvil the faster it cools which is why, historically, some small anvils had very hard faces. By the same token, the bigger the anvil the greater the tendency was for an overall softer anvil. The best of the modern anvil manufactures have the steel composition and heat treating technology necessary to keep an even hardness over the face of the anvil no matter what the size.
There are many methods of hardening the modern made anvil i.e. flame hardening, induction hardening, heating the entire anvil in a forge, heating the top 1/3 of the anvil in a forge, etc. Anvils are hardened by heating the anvil to critical temperature and quenching in either water, oil, or air depending on the kind of steel used in the anvil. The kind and quality of the steel used and how the anvil is hardened results in how hard the anvil is, the depth of the hardness, and the evenness of hardness.
Anvil height is always a compromise. Ideal height depends as much on hammer technique, hardy tools used, size and shape of the iron being worked, as it does on the blacksmith's height and arm length.
If you usually work on small (such as 1/2'” & under ) iron/bar your anvil can be as high as wrist high which might help save the back.
I began blacksmithing with wrist high anvils, but over the years I’ve lowered my anvil to knuckle height which is the height suggested in many old blacksmith books. I think my lowering the anvil is a result of my own hammer technique and the type of material I work on most of the time. Many other experienced blacksmiths like wrist high anvils, therefore I attribute that to their methodology and type of work they do.
If you often work on large iron (such as over 1” bar) a lower anvil is preferred. Also if a striker is used a lower anvil is preferred, unless the striker is particularly tall.
If you like to hammer on or near the far corner/edge of your anvil while standing perpendicular to the length of the anvil (common stance), or if you like to pound iron using the front corner/edge of your hammer, a lower anvil is handiest.
If you have to frequently raise your shoulder when you hammer, it could be your anvil is too high. An anvil that is too high results in shoulder aches and pains, while an anvil that is too low can potentially result in back problems.
If you have a high anvil, you can also use the anvil's far corner/edge without raising your shoulder by standing at the end of the anvil rather than at the side.
If your anvil rings loudly, tightly fastening it down to the base usually eliminates the noise (some anvils ring louder than others, but don’t assume yours is a loud one until it is tight to the base). The more anvil bottom surface that sits on the block/stump/stand the quieter it will be. Some blacksmiths put a lead sheet, piece of leather, piece of tar paper, or silicone caulk between the base and the anvil before tightly fastening it to the anvil base. Also, a chain around the waist of the anvil will dampen noise vibration. The chain can be used as part of the fastening system holding the anvil to the base, or just wrapped around the waist of the anvil.
It is well known that fastening a large magnet to the anvil will dampen sound. Unfortunately, whenever I tried it the magnet frequently fell off due to the vibrations of the pounding etc.
If your anvil base sits on 3 (three) small feet (roughly 6" to 8” diameter and at least 1/4" high) routered ,or otherwise manufactured, into the bottom of the base it usually sits much better on an uneven floor. see: Preparing a Stump - Base for an Anvil.
American Elm is a great wood for anvil bases as it is heavy and typically doesn’t split under the stress. Nevertheless it is not easy to find given the Dutch Elm Disease that killed most of the old elm trees. Talk to your local tree service as many still take down diseased elm trees. Honey locust and walnut also make good heavy anvil stands.
Oak stumps are usually heavy but they do split easily. Stumps subject to splitting can be hooped with iron around the top and bottom. The iron bands can be shrunk to the stump like on old wagon wheels, or a tightening bolt can be used.
It is very handy to have your anvil stump buried 2 or more feet into the shop floor. If the stump is solid and doesn't move, and if the anvil is solidly fastened to the stump (typically with chains) then bending forks etc. can be used in the hardy hole and larger iron can be bent. If the stump just sits on the floor, then when bending, the stump and anvil can move too much when bending iron. To bury the stump in the floor, the desired height of the anvil must be known, and the shop large enough so that the smith can work around the anvil. The blacksmith shop at Colonial Williamsburg has their anvils stumps buried 2 or more feet into the ground.
Anvils used with strikers should be fastened to the ground. For striker use, the anvil stump should be buried. If the stump can not be buried, then it should be designed to be bolted to the floor (if it is solid), or pegged to the ground/earth.
If the anvil stump is the same size as the base, then it does not get in the way when forging. A base that is large enough so that it extends under the horns can be a problem when forging larger or longer pieces. Also, a base that is too large might result in the blacksmith standing too far from the anvil.. Heavy and sturdy metal bases usually allow for the feet to be close to the anvil, although a round wood stump is more than adequate from a standing close standpoint.
There is good series of articles on anvils at: http://www.anvilfire.com/FAQs/anvil-0.htm, http://www.beautifuliron.com/gs_anvils.htm, and an 1890's article @ http://pages.friendlycity.net/~krucker/Anvil/HowAnvils.htm.
COAL & FIRE:
Coal Suppliers can be found at: http://www.anvilfire.com/gazette/index.htm, http://www.anvilmag.com/cs.htm, http://www.fholder.com/Blacksmithing/coal.htm, http://www.artmetal.com/project/TOC/COALCOKE.HTM, http://www.appaltree.net/aba/coal.htm, and http://www.penncoal.com/wst_page4.html. Coal can be found in Nebraska at the Little Giant Inc. in Nebraska City http://www.littlegianthammer.com/. Information about coal can be found at: http://www.iforgeiron.com/Blueprints/BP0051Good_Coal/BP0051Good_Coal.htm
About 8 newspapers one at a time loosely crumpled into an 8” diameter ball, the ball placed in the firepot, then mostly covered (not totally covered as the paper needs space to light it and burn) with yesterday's coke all the while keeping the paper burning by running the blower gently - makes starting any blacksmith coal forge fire easy and quick. Some blacksmiths twist the newspaper, tie the twisted papers in a knot, or make a doughnut of the twisted papers. Using wood kindling is typical in some areas of the country. Using coke/breeze made in yesterdays fire makes for smoke free fire starting.
Commercial coke is hard to start, but if care is taken can be started by the above method. The key is using enough newspapers or kindling.
With a little practice and good technique it should take 10 minutes or less to start and have a coal fire ready to heat iron. Typically as quick or quicker than a gas forge, particularly one with heavy insulation which takes 30 min. to an hour to heat up to a high temperature.
Commercial coke does not smoke much, and is therefore good for use in the city where there are neighbors.
Commercial coke, if used often, requires a fire pot thicker than is necessary for coal as coke burns hotter.
Some commercial coke sparks more than coal. This can be a problem if blacksmithing in a wooden building.
Blacksmith coal, of which there are many variations, is usually bituminous and called metallurgical coal. The most useful sizes are from 3/8" to 1 1/4" pieces. Larger pieces of coal cause cold spots in the fire as it blocks the air from the blower, and they take too long to coke up.
Blacksmith coal usually contains from 14,000 to 15,000 Btu's per pound (and is very low in sulfur and low in ash). Coal used in coal fired electrical generating plants has only 1/2 the Btu's per pound, and is generally not suited for blacksmithing - although it is not impossible.
When using a coal forge, each time the smith puts iron in the fire to be heated he/she should consolidate the coals in the firepot under the iron (everything in the firepot under forge table level). This keeps the burning coke/breeze from becoming hollow and allowing excess oxygen on the iron being heated..
Francis Whitaker used to consolidate the coal (preventing it from getting hollow) by using the iron being heated and forcing it downward into the burning coke/breeze each time it was placed in the fire.
The smith can also rake coke/breeze into the fire and press it down with the fire rake/shovel etc. All this prevents hollow fires that allow oxygen to get to the iron and corrode or erode it.
When using a coal forge the smith shouldn’t disturb the coke, coal, and fire in the firepot any more than necessary. Nevertheless, some, but not all coal requires that it be broken up when it sticks together or becomes too solid/crusty.
Rake or push freshly made coke toward/into both long sides of the fire pot as needed to replace burned up coke/breeze and keep the fire from becoming hollow. Refrain from stirring the coke, coals, or bringing up clinker (unless removing the clinker).
Coke/breeze and green coal need to always be kept separated. Burn only the coke. Make coke out of the coal that is on the table along the edges of the firepot.
Peter Ross, a very famous and highly-skilled blacksmith, said (at one of his demonstrations) that he could tell if a smith was not properly managing his fire if there was green coal mixed with the coke.
Perfectly flat forge tables (without a lip around the edges) allow iron of many dimensions and sizes to lay flat and stay at the top of the firepot (where it should be). This keeps 4” to 4 1/2” of coals under the iron, thus the fire is burning the oxygen out of the fire before it hits the iron. This can also make forge welding awkward sized forgings easier when the lip doesn't get in the way of placing the forging in the fire.
Coal with lots of fines (powdered coal) needs to be mixed with water to keep the fines from blowing away and to help it coke up into a mass.
A now common but not universal practice, for coal without fines such as coal that has been screened and washed (most Pocahontas III), is to not wet the coal before or during use.
Using wet coal does help convert coal to coke, and can help keep coal on the table from burning before it is needed. It is usually best to wet the coal in a bucket rather than on the forge table. As coal varies in it's properties, try your coal with or without water to see which works best with the coal you have.
Cold water poured on hot cast iron firepots of less than ¾” thickness lead to the firepot having a very short life. If water is to be used, it is best to water down the coal in a bucket before putting it on the forge table. It is a good practice to always ask, if you are using another persons forge, before you pour water on the coal on the table.
Here are two good articles on making charcoal the fuel used for approx. 96% of all the forge fires ever made: http://www.twinoaksforge.com/BLADSMITHING/MAKING%20CHARCOAL.htm, http://22.214.171.124/charcoalretort.htm
In a coal fire, the iron being heated should be surrounded by coke or "breeze" as it is sometimes called. The coke is made by burning coal around the edges of the firepot.
Iron should not be heated by burning green coal which is not as hot as burning coke. Iron should always be in contact and near "breeze" or "coke". Iron near burning coal is affected by and degrades due to impurities still in the coal. Therefore green coal should always have the impurities burned out of it by first making it into coke. Making coke is a continuous process and part of managing the fire. It is not made separately.
To continuously make coke there has to be enough coal on the table to keep the process going. I usually have a 6 inch to 8 inch high pile on both the long sides of the firepot. That coal is frequently raked toward the fire to keep the coking process working. Less coal on the table results in not enough coke when needed as when doing big iron or when forge welding.
In the typical coal fire, the iron bar is place horizontally at about table height (4 1/2 inches above the air inlet) and is surrounded by coke. On the forge table is green coal. In the firepot is coke and as the coke in and over the firepot is consumed by the fire, green coal is pushed to the edges of the fire, thus making new coke.
A general purpose coal fire has a trench down the middle where the iron being heated goes. The bottom of the coke trench is at table height. The iron bars being heated are generally flat on the table. Iron is surrounded by coke piled at least 2 inches higher than the forge table and/or iron bar. The green coal is piled at least 6 inches high (8 to 10 inches is OK) on the right and left side of the firepot. It is waiting to be pushed toward the firepot to make coke as needed.
In a coal forge, when heating iron it is best to have 3 1/2 to 4 1/2 inches (preferably 4 1/2 inches) of coke under the iron and approx. 2 inches of coke on top of the iron. This is the generally accepted system used to best eliminate oxygen from getting to the iron. The oxygen forms scale which degrades the surface of the iron and also makes forge welding difficult.
When heating for forging, it is necessary to be able to see the heat color of the iron in the fire. The iron must be seen either through the glowing coke (preferred method), or frequently the iron must be pulled out of the fire long enough to see the color. There are very experienced blacksmiths that just keep their iron on top of the coke and seem to prefer that method even when forge welding, but that is not necessarily the best way to begin learning to forge weld etc.
When forging, it is necessary to look at the forging from the side as well as the top. Otherwise thickness and shape are not well determined. Those new to blacksmithing often try to determine thickness etc. by looking only at the top of the iron where the hammer is hitting. It is interesting how often this simple, easy to understand, procedure is overlooked and the resulting shape ends up being less than desired (too thin etc.). Once the iron is too thin, it is often nearly impossible to make it thick again. Sometimes the metal can be upset to thickness, but often it can not or is difficult to do.
When forging, it is often best to leave the iron a little too thick and then as the piece is being finished, and after most procedures are completed, do any final thinning to final size as well as finish.
The skilled blacksmith turns, in his hand, the hammer handle in such a way that allows him/her to strike blows with the edges of the hammer face or the rounded corner of a hammer face, as well as using the flat face of the hammer. Using the rounded edge of the hammer face in drawing out results in the metal moving much faster. The divots made by the edge of the hammer face are then smoothed out with the flat face before they become too large and possibly cause cold shuts (metal folded over on itself and not welded).
Blacksmiths use hammers with various degrees of roundness to the face edges as well as various crown radius on the face. My general use hammer has a minimal crown to the face and a minimal radius to the edges, but that is not universal among blacksmiths.
Often a new store bought hammer (hardware store or lumber yard) for general use needs to have the face ground or forged away so the original machined, and typically large, 45 degree chamfer or corner is just about gone. Then a new slight crown is put on the face and a small smooth radius put on the edges. Also the thin peen end of the hammer is ground down to make it approx. 3/8 to1/2 of an inch wide with a slight crown both ways and a slight radius on the edge. Hammer faces and edges need to be smooth so as to not leave unwanted sharp edged marks on the forgings.
For smoothing the faces and edges of hammers, the best product I've found is by 3M. It is their Scotch-Brite surface conditioning disks. They come in course, medium, fine, and very fine. The come in all angle grinder sizes, but I like the 7" round size and use it with a 7" angle grinder. These disks are useful for polishing about anything such as tools, anvil faces, and forged items. They can be purchased at supply houses for machine shops.
Typically, on a hammer, the face crown and edge radius is the same on both the flat face and the peen.
The hammer as well as the anvil can always be thought of as a die forming the metal. Different shaped dies (hammers, parts of hammers, parts of anvils, etc.) forge the metal into the shapes desired.
See also: ABANA's Forging Fundamentals Controlled Hand Forging Lessons By the ABANA Educational Programs Committee @ http://abana.org/resources/chf.shtml
If you use the typical blacksmith finish (1/3 turpentine, 1/3 wax, 1/3 linseed oil, small amount of Japan Drier), leave out the Japan Drier if you use the finish on hot iron as the smoke and vapor from the Japan Drier can be harmful to your health (contains heavy metals – at least it used to).
Japan Drier, an ingredient in the above finish, will help the normally slow to dry finish dry, when applied on cold on cold metal.
If your firepot is shallow (less than 4 inches) and/or you are having trouble forge welding, it helps to use a bigger and higher pile of coal/coke in order to raise the point in the fire to where the flame is not oxidizing. Place the iron being heated at least 4 inches above the air inlet. If needed, it helps to surround the firepot with firebricks which essentially makes for a deeper firepot.
IMPORTANT: All firepots require a blower powerful enough to blow enough air, through the coke when compacted, to keep the hottest part of the fire at the top of the firepot. The deeper the firepot the more powerful the blower/blast needs to be to keep the hot useable part of the fire at table height.
Centaur Forge Vulcan firepots being thinner than some others can crack when water is used on the fire or mixed w/coal. Firepots particularly crack when enough cold water runs down into a hot firepot. Thicker firepots (5/8” and thicker) are not as susceptible to cracking. Thicker firepots can be purchased from Roger Lorance Metalsmith @ 6091 North 3850 East Rd., Bellflower, IL 61724, phone 309-475-9012 with an e-mail address of firstname.lastname@example.org, Laurel Machine & Foundry (http://store.lmfco.com/cgi-bin/index.pl?a=v&d=1), Little Giant (http://www.littlegianthammer.com/), and Thak Blacksmith http://www.thak.ca/firepots.html (this is a 6" deep firepot which is good). The SOFA/Zeller fire pots are available for sale through Bob Cruikshank (937) 323-1300. Also, the thicker firepots are less susceptible to burn out when commercial coke is used. Centaur sells a round coke firepot which is thicker than their coal firepots, but they are also shallower which makes them not as useful for most coal fires.
4 ½” or more of coal firepot depth is ideal for many modern day purposes as they have enough space under the iron being heated. The space when filled with burning coke helps burn up the oxygen coming from the blower; thus oxygen causing scale is kept to a minimum. A firepot that is a little shallow can be made deeper by raising the table above the firepot (bricks, cement, etc.). Most but not all of the above mentioned firepots are less than 4 1/2" deep.
Deep firepots are especially important when forge welding. The fire must also be kept from becoming hollow or the oxygen doesn’t get burned up by the coals and there is less heat produced.
Resist the temptation to stick the iron down below the level of the top of the firepot as the iron is adversely affected by the excess oxygen below that level.
Coal forge tables come in all sizes, but I like a forge table to be pretty close to 34 inches wide and used with a 14 inch long firepot. If a forge is too wide, the table can interfere when placing odd shapes of iron in the fire. If it is too narrow, then the iron always needs some type of support in addition to the table. Some type of a removable stand or pull out can be used to hold long irons in the fire. I also like the table to have enough room on right side (away from the chimney) of the firepot to be large enough to hold a 5 gal. bucket of coal along with some fire tools, and enough room on the left side of the firepot (chimney side) to hold a pile of coal big enough so that the coke can be raked into the fire from both sides of the fire pot rather than just one side. See: Student Coal Forges
Coal forge height is generally the same height as the anvil. Too high and the blacksmith has to raise his iron and arm too much, too low and the blacksmith has to bend over to look at the iron. Go for a comfortable height that doesn't require more work than necessary to put iron in and out of the fire.
Iron or metal coal forge tables get hot to the touch unless covered with refractory, clay, brick, cement, etc.
Coal forge chimneys should be a minimum of 12 inches round or square and a minimum of 16 feet high if you want it to draw and not leave smoke in the room. One of my first forge chimneys was 8" in diameter and 34 ft. high. I always had to have another fan in the room drawing out the smoke that didn't make it up the chimney.
I have seen some smaller diameter chimneys (8 and 10 inch) work fairly well when a roof wind turbine ventilator is attached to the top.
The higher the chimney, the better they work.
Forge chimneys do not need smoke chambers unless they are in a building that is totally air tight. Look at old chimneys in professional blacksmith shops, both brick and metal , and you will not find many, if any, smoke chambers.
Chimneys should be at least 2 feet higher than anything within horizontal 10 feet distance from the top of the chimney including the roof or a tree, etc.
Forge chimney caps need to be set high enough so that wind blowing across the top will have plenty of space between the top of the chimney and the bottom of the chimney cap i.e. a 12” diameter pipe should have at least 12” of space between the top of the pipe and the bottom of the chimney cap.
Brick, cement block, rock, or earth chimneys work better than metal chimneys as they hold in the heat which is one key component in causing chimneys to draw. The warmer the air, as it rises, the better the chimney will draw. Steel chimneys allow the hot air to cool much faster than if the chimney were cement, brick, stone, mud, etc. Steel chimneys on the outside of buildings cool even faster. See a nice brick forge at: http://sofablacksmiths.org/events/valleyview/valleyforge1.htm.
Most gas forges that are made of hard castable or firebrick often take 30 to 60 minutes to warm up to forging temperature. They also take a long time to cool down which is good if you want to use your forge for annealing (softening) steel.
Gas forges made of heavy insulation take a long time to cool down and can be a potential night time fire hazard in an unmanned shop.
Gas forges that are made of hard castable or firebrick hold their heat well when cold iron is placed in them.
Most gas forges made of hard castable insulation are not bothered by flux. Gas forges with blanket insulation need something in the bottom which can withstand flux (if you flux in your forge).
Gas forges w/blanket insulation warm up and cool fast. That is sometimes good and sometimes not so good.
For serious forging, a radial blower is the only type of forge blower that has the necessary pressure to blow through 4 ½” of packed glowing coke. That is particularly important when forge welding and if a deep firepot is used. The radial fan blower is the type used in the blower fans of the old lever and hand crank forges . Squirrel cage fans do not generate the necessary pressure for quick heats in big iron. The best commercial electric blower that I know of is made by Centaur Forge, # PB50VS, www.centaurforge.com/ as shown:.
Good electric forge blowers can be made from old clothes dryers as they usually have great radial fans, although they may not be made of metal which is OK considering the price. Another source of good forge blowers are old pipe organs when they can be found.
The larger hand crank forge blowers such as the Champion No. 400 have the necessary pressure for good forge welding even when flux is not being used as is common in England. Originally these blowers were made in different sizes. These blowers with ball bearings are usually the easiest to crank and last the longest.
Hand crank forge blowers are sometimes difficult to repair (bearings etc.), but it is not impossible.
The old forge bellows, if made and working properly, have the necessary pressure for heavy work.
Wet gloves lose their insulation value and become conductive; therefore heat can easily pass through. Burns can occur more quickly.
Kevlar gloves are much more fire resistant than cotton. Cotton catches fire easily. Leather can get hot on the inside too quickly.
Fuzzy Kevlar gloves are more insulating than the thinner more tightly woven Kevlar gloves. The thin Kevlar gloves allow for more feel.
The cuffs on the fuzzy Kevlar gloves are just cotton and can catch fire.
Always be careful with heat treated steel! It can be brittle and dangerous. It can easily break or shatter and extremely sharp pieces can fly around the room with the possibility of harming people. Become familiar with "tempering" steel so that it is not too hard and dangerous.
For heat treating information see: Heat Treating Guide - Temperatures
Beginning blacksmiths can make good use of automobile and truck springs to make their chisels and punches. Keeping in mind that these used materials may already have stress cracks etc. nevertheless, it is inexpensive practice. Then when the blacksmith is satisfied with his skill level, wants to try better steel, he can make tools out of new spring steel (5160) or as noted below. Some blacksmiths continue to use recycled material and never go to the new steel. Larger items such as hammers, hardy tools etc. can be made from used and sometimes broken jack hammer bits (different steels) if available or large truck axels (typically 4140).
Very serviceable hammers can be made from 1040 to 1050 steels. When these are used the tool can be simply quenched in water and used without tempering. Sometimes tempering is desirable around the thin sections of the handle hole or on other thin sections such as thin peen ends. 1140 can also be used like 1040. 1140 has elements which make it machine easier, but is sometimes more available. The last 2 numbers in the steel type indicate the % of 1 % of carbon in the steel. The first 2 numbers indicate the alloy elements with 10XX being plain carbon and essentially no other elements such as chromium, vanadium, etc.
Steel with over .5% carbon such as 1055 (older Caterpillar track pins) or 5160 (typical automobile & truck springs) are typically quenched in oil. Even water hardening steels in thinner sections, such as when making chisels, are typically quenched in oil. Hardening steel, for the blacksmith, is not an exact science. For example some blacksmiths make tools of 5160 and quench them in water instead of oil. Sometimes the method used is "whatever you can get away with" or "trial and error".
H13 (typical injection molding machine push pins) at about $3.00 per pound (year 2006 prices) make good blacksmith hot cut tools. It is also easy for the blacksmith to heat treat adequately for his purposes. H13 does not get as hard as S1, S7, 5160, or W1 etc., but is adequate for hot cut punches, chisels, and drifts.. H13 can be purchased from Crucible Service Centers: www.crucibleservice.com. H13 data sheet @ http://www.crucibleservice.com/datash/dsNuDieVv13.pdf & http://cartech.ides.com/datasheet.aspx?i=101&c=TechArt&E=
H13 is an air hardening steel and therefore doesn’t stand cooling in water well. It will still hold an edge or shape at a dull red. Generally, when in use, a blacksmith can quickly dunk the H13 tool in water but he/she is always taking a chance on the tool cracking when cooling in water. Some blacksmiths that do not want to cool their H13 tools in water, make 2 or 3 of the same tool in order to have at least 1 tool cooling while one is in use.
S1 – Crucible's Atha Nu is about $4.50 per pound (year 2006 prices), is a shock and heat resistant steel that can be used for blacksmith cold as well as hot cut tools. It can also be quickly cooled in water in use, but it is an oil hardening steel. It is not as heat resistant as H13. but more so than plain carbon steels. It is capable of high hardness. The biggest problem is that Crucible, the company that makes Atha Nu, no longer makes it in the sizes blacksmith use per my phone call to them on 3/6/06. Little Giant Hammer, Inc. @ http://www.littlegianthammer.com/ still has some for sale under "tool steel" on their web page. S1 made by other companies does not have the quite same composition as Atha Nu and not quite as suited for blacksmith tools and use (but I use some).
S7 (air hardening) is commonly used by blacksmiths for hot cut tools. It is readily available and a data sheet can be found at: http://www.crucibleservice.com/datash/dsS7v6.pdf & http://cartech.ides.com/datasheet.aspx?i=101&c=TechArt&E=114
Plain carbon steels lose all of their hardness at approx. 600 degrees F. which is approx. a dark blue oxidizing color. That is why when the standard carbon steel knife is ground too quickly on a grinding wheel, and the thin edge turns blue, the hardness in the edge is lost.
Drifts are generally made from A36 ( approx. .25% Carbon) which is the common structural steel in use today. It is the most readily available steel today.
Many blacksmith tools can be made of A36. They might not last as long, but are often suitable. A36 can be quenched in water to make them a little harder. Also the "Gunther" quench might make them harder than if plain water is used. The Gunther quench should only be used on steels with less than .3% carbon or the steel will get too hard and crack etc.
Cold rolled steel has a little less carbon than A36. It has approx. .2% carbon. Generally found in round and square bar stock. It is more precise in size than hot rolled steel bar stock. Cold it has a harder surface due to the cold rolling which also stresses the skin of the steel.
Flat plate steel can be readily found in A36 or in plain carbon steels with less carbon than A36. Sometimes as little as .09% is fairly common.
Many shop tools can be made of steel with a higher carbon content than A36, such as 1045 or 1095, and not heat treated after forging. These might be suitable for punches, bending forks, swages, fullers, etc.
THE SHOP FLOOR:
Shop floors made of smooth cement make sweeping up easy and allow for easy movement of equipment.
Cement floors are not known to be easy on the feet.
Wooden floors are easy on the feet, and let the blacksmith know (smoke) if a piece of hot iron has dropped on the floor. Wooden floors were common 75 or more years ago, and having them probably resulted in some building fires.
Peter Ross has a shop floor made of 4 inch square pieces of Locust set into the floor with the end grain up.
Dirt floors can be hard to sweep, and often get dry, dusty or muddy. Sand, clay, cement, oil, and cinders are possible additives that can be mixed with a dirt floor to help solidify it. Moving equipment can sometimes be more of a problem than on a cement floor. Tools and other items can get lost in the floor if it is made of loose material.
Some blacksmiths like a crushed stone powder or gravel, typically fairly fine in nature.
FOR MORE INFORMATION: ODBSA Old Dominion Blacksmith Association has a Beginner's Corner with good information. Check it out!