[ Pobierz całość w formacie PDF ]
//-->BLACKSMITHINGIntroductionBlacksmithing transforms metals inits physical structure andappearance by heating andhammering.In this brief, materials are restrictedferrous metals, that is, the range ofirons and steels.The smithy contains five main thingsto aid the blacksmith in their work.There needs to be a heat source orhearth to get the material red hot tobe able to mould it. There must be acooling system close to hand, notFigure 1: The Azagarafa Blacksmith Society ofonly for quenching material when itAzagarafa village in the North Darfur region ofhas been worked, but also as aSudan. Photo: Practical Action.safety aspect in case of embersrising/ or burning taking place while the blacksmith is working.Experience is critical to the skilled smith: skills still require practise.The essentials for blacksmithing are:•A means of heating.•A means of rapid cooling.•Support for the work pieces.•Shaping and deforming implements.•Work material.HeatingA form of heating hearth or forge is needed in which a firecan be maintained. Forced air will be required to assist inthe generation of sufficient heat for workpieces to reach atleast forging temperature, say 1000° and preferablyCwelding heat which is another 100/2000° higherCdepending on the materials involved.The hearth can be formed by a stone or brick structure ora metal table structure. A hood or chimney is requiredwhen the hearth is indoors.Ideally, the hearth should be at least 2m (6') deep and 2m(6') wide. The hearth needs a strong stone slab or ironplate along the working ledge which should be a littlelower than domestic table height from the ground, a tallsmith would benefit from having this height increased stillfurther so as to reduce fatigue.Traditionally bellows are used to supply air piped throughthe left hand side of the furnace, if the smith is righthanded, through an iron tube.Figure 2: A man workinghis forge blower.Photo credit: Zul / PracticalAction.BlacksmithingPractical ActionA pair of bellows or, more recently, an air fan, needs to be fitted into the forge via iron tubes,to allow air to be blown into the fire. Quite sophisticated tubes exist in some countries:English smiths have water-cooled ones traditionally called tueirons. Alternatively, ceramictubes can be used without a cooling system. There are various types of fan,Figure 2b: The blowerFigure 2a: The forge andwater called TueironsThe traditional bellow and some crank fans require manual input; another option is anelectric fan where available.The heating medium can be charcoal if clean walnut-size gas coke is not available. If coke isused always screen it first by using a fine mesh riddle so as to separate coke dust andphysical impurities, which may have become mixed with the fuel. Always keep the fire freefrom clinker: as soon as the essential heating area becomes too hot, clinker is formed andthis needs carefully removing with the aid of a poker without losing the fire altogether. Mostsmiths-suspend a coke guard over the arch of the hearth, which also helps to improvenatural draught slightly.Cooling and QuenchingThe water trough–As mentioned earlier it is important to have a bucket or trough close athand not only for quenching but also in case of burning. So the main use for the water is toquench the hot steel to cool or temper it. The bucket should be large enough to totallyimmerse all pieces of work easily. The volume of the trough should be at least 25 litres (5Gallons UK) so this is possible.The oil container–This container should be about the same size as the trough as it will beused for the same material, which needs to be quenched. The important thing to note aboutoil and therefore the design of the oil container is that the oil can some times catch fire.Because of this the container should have a hinged lid, which can be shut depriving theflames of oxygen should the oil catch fire. (Fire only usually occurs when there is insufficientoil and so it is heated up and begins to burn)The container holding the oil should be situated in a separate place, either outside orsomewhere else in the smithy. It should not be situated by any other combustible objects. Itis important to note that the forge and oil container should both be surrounded by metalflooring, not wood, in case hot coals are dropped or flash fires occur.2BlacksmithingPractical ActionSupport for working materialAnvilAn anvil of some kind is essential equipment and whilstone of many varieties could be selected, it is probablethat an improvised anvil made of stone with an iron insertmight suffice in an emergency. Some anvil patterns areillustrated below, see figure.A typical anvilOld rail tracksFigure 3a: Blacksmiths. Photocredit: Practical Action / TimReevesAn improvised anvil madefrom an old castingFigure 3b: Different types ofAnvil layouts3BlacksmithingPractical ActionShaping/ Deforming ToolsAll tools to deform malleable iron or steel consist of clams, hot and cold sets, various tongsfor handling the work piece and, of course, hammers. These are illustrated as follows,Sledge Hammer– Very Heavy hammer usually used by the blacksmithsassistant to work the large pieces of metal.Cross Peen Hammer – Smaller hammer with two ends for different effects.Used in most forging processes.Hot Chisel– Used for cutting hot metal, by striking with a hammer. This toolis not hardened and should not be used to cut cold material, only heated.Cold Chisel– Used to cut cold material, never hot material. This tool ishardened and tempered so it is sharp and strong so it can cut cold material.Hot set– Similar to a chisel but with a long handle. It is usually struck by asledgehammer operated by the blacksmiths assistant. Not for cold material.Cold set– This is used for cold material as the name suggests. It again hasa long handle like the hot set. Again it is struck by a sledgehammer. Thecold set looks similar to the hot set apart from its thickness and angle ofblade.Round Punch– Creates a round hole by driving the punch through a sheetof hot material. Alternative to the drill.Tongs– Used to hole material when it has been hated and is ready forwork. These can be made in the forge, for different pieces of work. Theheads can be shaped to grip different sizes and shapes of material.Bottom Fuller– Normally used with a top filler, to create rounds or indentsin material.Top Fuller– Used to make grooves in hot metal. Both the top and bottomfuller can be made from mild steel.Figure 4: Tools RequiredMechanical ToolsThere are many varieties of mechanical tools,which might be useful amongst which are; a fly-press, drilling machine, drop hammers and tilthammers can be used, powered by a motor orwaterFigure 5: A mechanical tilt hammer using old carcomponents.Work MaterialsThe majority of material used by blacksmiths is that obtained from scrap yards and old cars.Sometimes materials may be bought in but often it is not necessary, as there are othermaterials, which can be reused.4BlacksmithingPractical ActionMild Steel– Can be found in sheet form in car body panels, truck chassis and oil drums. Inbar form mild steel appears in reinforcing rods on construction sites, although these oftenhave a slightly higher carbon content than true mild steel. You make hoes and hinges fromsheet steel and tongs, set handles and sickles (toothed pattern), from bars.When working mild steel it should be forged at a bright yellow heats as seen in the shade(just below the temperature where it starts to give off sparks) Some minor bending andcutting can be done cold. It is not possible to harden mild steel enough for cutting tools (highcarbon steel is better for this) but it is easier to fire weld than other materials.Medium Carbon Steel– Many vehicle parts and mechanical machine parts are made frommedium carbon steel. Vehicle shafts, tractor plough discs and plough mould boards are afew but there are others. You can use medium carbon steel for Hoes and punches similar tomild steel, but also Hammers and hot chisels, for when you are making new tools for specificjobs.Working medium carbon steel needs to be done at a temperature lower than that of mildsteel, but still at a heat where it is yellow. The extra carbon I the steel means that it ispossible to harden it but no t to the extent of high carbon steel. It can be difficult to fire weld,but with practice it is possible.High Carbon Steel– Sources of high carbon steel can be found in the following,Suspension coil spring, torsion bar, vehicle leaf spring, Anti roll bar, Wood Saw, Largehacksaw. As it is high carbon it can be hardened as mentioned before and so is very usefulto make tools from when working I the forge. Tools like cold chisels, cold sets, knives, woodchisels, plane blades, axes, adzes, wood and stone carving tools and tin snips.High Carbon steel is the most useful of the three steels described. It can be hardened, whichmeans it is suitable to make cutting blades from, which a lot of the mentioned tools need tofunction. It needs to be forged at an orange/yellow heat, but not as hot as the mild andmedium carbon steels. It is very hard to fire weld with this material but it can be welded tolow carbon steels with practice.Practical approach to workingAlways work out, either mentally or on a piece of paper, the steps involved to make the itemto be made. Never start and hope that it will come out right because this is rarely asuccessful practice. Time spent thinking out the way in which each part of the forging isgoing to be manipulated will pay handsomely in the long run. It is a question of 95% what todo and 5% doing it. Once a plan is clearly formed, cut off the correct weight of material andstart heating. Remember it is nearly impossible to increase the section by normal anvil workso start with the largest section material needed to reach the finished size required. Besparing with the use of your hammer: wasted blows only tire you and create bad marks in theworkpiece. Never consider a job unworthy of making special tools to fulfil a particular part ofthe job.Many items made may be individual creations but repeats are sometimes required and it isgood to keep a record of each significant job in note form in a pocket book. Keep a record ofany drawings you have made and it may be as well to start a formal recording system.Always finish off the work you start by filing the rough edges and leaving the piece in a statewith which you are proud.CalculationsSometimes a smith is faced with finding out mathematical answers to questions, for instance,how much material will be required to produce a bolt so long? If a sample exists in a similarmaterial, it is possible to weigh the sample and this gives the weight of the minimum materialrequired to forge a replacement. It is wise to add some more material to the minimum so asto allow for wastage and for holding the workpiece, which may be an awkward shapeotherwise. Volumes are being dealt with by the smith all his working life and this meansmeasuring the length, the breadth and the height of a job so as to find a figure, which thenneeds multiplying by a coefficient factor to obtain a practice weight. Over a short period a5 [ Pobierz całość w formacie PDF ]
zanotowane.pl doc.pisz.pl pdf.pisz.pl jajeczko.pev.pl
//-->BLACKSMITHINGIntroductionBlacksmithing transforms metals inits physical structure andappearance by heating andhammering.In this brief, materials are restrictedferrous metals, that is, the range ofirons and steels.The smithy contains five main thingsto aid the blacksmith in their work.There needs to be a heat source orhearth to get the material red hot tobe able to mould it. There must be acooling system close to hand, notFigure 1: The Azagarafa Blacksmith Society ofonly for quenching material when itAzagarafa village in the North Darfur region ofhas been worked, but also as aSudan. Photo: Practical Action.safety aspect in case of embersrising/ or burning taking place while the blacksmith is working.Experience is critical to the skilled smith: skills still require practise.The essentials for blacksmithing are:•A means of heating.•A means of rapid cooling.•Support for the work pieces.•Shaping and deforming implements.•Work material.HeatingA form of heating hearth or forge is needed in which a firecan be maintained. Forced air will be required to assist inthe generation of sufficient heat for workpieces to reach atleast forging temperature, say 1000° and preferablyCwelding heat which is another 100/2000° higherCdepending on the materials involved.The hearth can be formed by a stone or brick structure ora metal table structure. A hood or chimney is requiredwhen the hearth is indoors.Ideally, the hearth should be at least 2m (6') deep and 2m(6') wide. The hearth needs a strong stone slab or ironplate along the working ledge which should be a littlelower than domestic table height from the ground, a tallsmith would benefit from having this height increased stillfurther so as to reduce fatigue.Traditionally bellows are used to supply air piped throughthe left hand side of the furnace, if the smith is righthanded, through an iron tube.Figure 2: A man workinghis forge blower.Photo credit: Zul / PracticalAction.BlacksmithingPractical ActionA pair of bellows or, more recently, an air fan, needs to be fitted into the forge via iron tubes,to allow air to be blown into the fire. Quite sophisticated tubes exist in some countries:English smiths have water-cooled ones traditionally called tueirons. Alternatively, ceramictubes can be used without a cooling system. There are various types of fan,Figure 2b: The blowerFigure 2a: The forge andwater called TueironsThe traditional bellow and some crank fans require manual input; another option is anelectric fan where available.The heating medium can be charcoal if clean walnut-size gas coke is not available. If coke isused always screen it first by using a fine mesh riddle so as to separate coke dust andphysical impurities, which may have become mixed with the fuel. Always keep the fire freefrom clinker: as soon as the essential heating area becomes too hot, clinker is formed andthis needs carefully removing with the aid of a poker without losing the fire altogether. Mostsmiths-suspend a coke guard over the arch of the hearth, which also helps to improvenatural draught slightly.Cooling and QuenchingThe water trough–As mentioned earlier it is important to have a bucket or trough close athand not only for quenching but also in case of burning. So the main use for the water is toquench the hot steel to cool or temper it. The bucket should be large enough to totallyimmerse all pieces of work easily. The volume of the trough should be at least 25 litres (5Gallons UK) so this is possible.The oil container–This container should be about the same size as the trough as it will beused for the same material, which needs to be quenched. The important thing to note aboutoil and therefore the design of the oil container is that the oil can some times catch fire.Because of this the container should have a hinged lid, which can be shut depriving theflames of oxygen should the oil catch fire. (Fire only usually occurs when there is insufficientoil and so it is heated up and begins to burn)The container holding the oil should be situated in a separate place, either outside orsomewhere else in the smithy. It should not be situated by any other combustible objects. Itis important to note that the forge and oil container should both be surrounded by metalflooring, not wood, in case hot coals are dropped or flash fires occur.2BlacksmithingPractical ActionSupport for working materialAnvilAn anvil of some kind is essential equipment and whilstone of many varieties could be selected, it is probablethat an improvised anvil made of stone with an iron insertmight suffice in an emergency. Some anvil patterns areillustrated below, see figure.A typical anvilOld rail tracksFigure 3a: Blacksmiths. Photocredit: Practical Action / TimReevesAn improvised anvil madefrom an old castingFigure 3b: Different types ofAnvil layouts3BlacksmithingPractical ActionShaping/ Deforming ToolsAll tools to deform malleable iron or steel consist of clams, hot and cold sets, various tongsfor handling the work piece and, of course, hammers. These are illustrated as follows,Sledge Hammer– Very Heavy hammer usually used by the blacksmithsassistant to work the large pieces of metal.Cross Peen Hammer – Smaller hammer with two ends for different effects.Used in most forging processes.Hot Chisel– Used for cutting hot metal, by striking with a hammer. This toolis not hardened and should not be used to cut cold material, only heated.Cold Chisel– Used to cut cold material, never hot material. This tool ishardened and tempered so it is sharp and strong so it can cut cold material.Hot set– Similar to a chisel but with a long handle. It is usually struck by asledgehammer operated by the blacksmiths assistant. Not for cold material.Cold set– This is used for cold material as the name suggests. It again hasa long handle like the hot set. Again it is struck by a sledgehammer. Thecold set looks similar to the hot set apart from its thickness and angle ofblade.Round Punch– Creates a round hole by driving the punch through a sheetof hot material. Alternative to the drill.Tongs– Used to hole material when it has been hated and is ready forwork. These can be made in the forge, for different pieces of work. Theheads can be shaped to grip different sizes and shapes of material.Bottom Fuller– Normally used with a top filler, to create rounds or indentsin material.Top Fuller– Used to make grooves in hot metal. Both the top and bottomfuller can be made from mild steel.Figure 4: Tools RequiredMechanical ToolsThere are many varieties of mechanical tools,which might be useful amongst which are; a fly-press, drilling machine, drop hammers and tilthammers can be used, powered by a motor orwaterFigure 5: A mechanical tilt hammer using old carcomponents.Work MaterialsThe majority of material used by blacksmiths is that obtained from scrap yards and old cars.Sometimes materials may be bought in but often it is not necessary, as there are othermaterials, which can be reused.4BlacksmithingPractical ActionMild Steel– Can be found in sheet form in car body panels, truck chassis and oil drums. Inbar form mild steel appears in reinforcing rods on construction sites, although these oftenhave a slightly higher carbon content than true mild steel. You make hoes and hinges fromsheet steel and tongs, set handles and sickles (toothed pattern), from bars.When working mild steel it should be forged at a bright yellow heats as seen in the shade(just below the temperature where it starts to give off sparks) Some minor bending andcutting can be done cold. It is not possible to harden mild steel enough for cutting tools (highcarbon steel is better for this) but it is easier to fire weld than other materials.Medium Carbon Steel– Many vehicle parts and mechanical machine parts are made frommedium carbon steel. Vehicle shafts, tractor plough discs and plough mould boards are afew but there are others. You can use medium carbon steel for Hoes and punches similar tomild steel, but also Hammers and hot chisels, for when you are making new tools for specificjobs.Working medium carbon steel needs to be done at a temperature lower than that of mildsteel, but still at a heat where it is yellow. The extra carbon I the steel means that it ispossible to harden it but no t to the extent of high carbon steel. It can be difficult to fire weld,but with practice it is possible.High Carbon Steel– Sources of high carbon steel can be found in the following,Suspension coil spring, torsion bar, vehicle leaf spring, Anti roll bar, Wood Saw, Largehacksaw. As it is high carbon it can be hardened as mentioned before and so is very usefulto make tools from when working I the forge. Tools like cold chisels, cold sets, knives, woodchisels, plane blades, axes, adzes, wood and stone carving tools and tin snips.High Carbon steel is the most useful of the three steels described. It can be hardened, whichmeans it is suitable to make cutting blades from, which a lot of the mentioned tools need tofunction. It needs to be forged at an orange/yellow heat, but not as hot as the mild andmedium carbon steels. It is very hard to fire weld with this material but it can be welded tolow carbon steels with practice.Practical approach to workingAlways work out, either mentally or on a piece of paper, the steps involved to make the itemto be made. Never start and hope that it will come out right because this is rarely asuccessful practice. Time spent thinking out the way in which each part of the forging isgoing to be manipulated will pay handsomely in the long run. It is a question of 95% what todo and 5% doing it. Once a plan is clearly formed, cut off the correct weight of material andstart heating. Remember it is nearly impossible to increase the section by normal anvil workso start with the largest section material needed to reach the finished size required. Besparing with the use of your hammer: wasted blows only tire you and create bad marks in theworkpiece. Never consider a job unworthy of making special tools to fulfil a particular part ofthe job.Many items made may be individual creations but repeats are sometimes required and it isgood to keep a record of each significant job in note form in a pocket book. Keep a record ofany drawings you have made and it may be as well to start a formal recording system.Always finish off the work you start by filing the rough edges and leaving the piece in a statewith which you are proud.CalculationsSometimes a smith is faced with finding out mathematical answers to questions, for instance,how much material will be required to produce a bolt so long? If a sample exists in a similarmaterial, it is possible to weigh the sample and this gives the weight of the minimum materialrequired to forge a replacement. It is wise to add some more material to the minimum so asto allow for wastage and for holding the workpiece, which may be an awkward shapeotherwise. Volumes are being dealt with by the smith all his working life and this meansmeasuring the length, the breadth and the height of a job so as to find a figure, which thenneeds multiplying by a coefficient factor to obtain a practice weight. Over a short period a5 [ Pobierz całość w formacie PDF ]