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TOPIC: 6. TOOLS USED ON BUILDINGS
INTRODUCTION: This section teaches students the different tools used on buildings, how they are used and maintained properly.
We select those tools first which are needed from the very beginning of the school, like hammer, saw, trisquare and chisel. An idea would be to teach the basic tools and their maintenance in the beginning of the first year and later in the year the other tools and their maintenance.
OBJECTIVES:
6.1. Students should be able to name all marking out tools, their parts, their application and how to handle and use them correctly.
6.2. Students must be able to identify all the parts of a chisel and plane and be able to use them in the correct way.
6.3. Students have to know the procedure for sharpening a plane in theory and practise, on the grinder as well as on the oilstone.
6.4. Students should be able to identify the different hand saws, their characteristics and their uses.
6.5. Students have to be able to sharpen a saw by following the four chief operations.
6.6. Students should be able to state all parts of a hand drill and a bit brace and must be able to use them correctly.
Students also must be able to identify the different bits, their characteristics and their uses.
6.7. Students should be able to identify and use driving tools correctly.
6.8. Students should know all guiding tools and be able to use them correctly.
6.9. Students should be able to name all the bricklaying tools and their uses.
6.10. Students should be able to identify the different concrete-working tools and be able to use them correctly.
METHODS: Teaching the correct use and maintenance of tools is more effective if it is combined with practical exercises and demonstration in the workshop.
However, sometimes there are not enough tools for the whole class especially grinder and stones for sharpening practise.
An idea would be to split up the class into smaller groups when practising in the workshop.
For the lesson in the classroom we prepare photocopies of the different tools and samples of each tool for explanation of their purpose, the correct use and its maintenance.
NOTE: At the end of this topic a worksheet is prepared for the students to fill in in their own time for assessment later.
Tools are classified according to the work they do, into various groups of which the following are the main ones:
Marking out tools, sharp edge cutting tools, Tooth cutting tools, Boring tools, Driving tools, Sharpening tools, Guiding and Testing tools and Brick laying tools.
a) Tape measure: - Is used for measuring straight lines and setting out work. Usually graduated in mm and cm length and inches.
Figure
b) Pencil: - Is used for marking and setting out lines on the prepared timber. It should be used an HB or H pencil as it keeps a sharp edge for longer periods. A soft pencil gets blunt quickly.
Figure
c) Try square:
- These are made either all metal or with a wooden stock and metal blade. They are supplied with blades ranging from 100 mm to 450 mm in length and are used for either squaring lines across the face or edge of timber, for testing the squareness of the edge from the face, and for testing the flatness of the timber surface.
Figure
- Trueness of the trysquare: Care should be taken exercised when testing it. The test is - place the stock against the straight edge of a piece of wood and mark a fine line against the edge of the blade; then reverse the stock, and if the edge of the blade coincides with the line, the square is true; if not, half the difference will be the amount of the error. Both edges of the blade should be tested and if necessary corrected by filing.
Figure
d) Combination Try Square: - It is a tool that combines four marking-out tools in one. It has a slotted blade passing through a stock which gives a right angle on one side and a mitre angle on the other. Attached to the stock is a small spirit level for testing level and uprightness. Because of the adjustable stock it is possible to use it as a marking gauge.
Figure
e) Sliding Bevel: - The sliding bevel can be set to any angle other than a right angle. These can be obtained with either a wood or metal stock, with a sliding blade from 150 mm to 300 mm length which is fixed, in the case of a wooden stock by a screw or lever nut, and in the case of a metal stock by a blade clamping screw which runs down the centre of the stock.
Figure
a) Bevelled edge firmer chisel: - The have bevelled edges and range in size from 100 mm to 200 mm length and from 2 mm width increasing by 2 mm up to 12 mm, and then by 3 mm up to 38 mm width. It is a general utility tool, being used for short paring work and for light mortising. For the latter, a mallet is used in conjunction with the chisel to force it into the fibres. The blade is secured to the handle by means of an iron tang driven into the handle. By wooden handle there is a brass ferrule around the blade end of the handle.
Figure
b) Metal smoothing plane: - The metal smoothing plane is a cutting tool, which is used when producing straight, flat and square surfaces. The plane is also used to produce a finished unit of the required shape and smooth the wood surface. Smoothing planes range in size from 150 mm - 250 mm in length and 50 mm - 60 mm in width. The smoothing plane consists of the metal base, the mouth opening, the toe, the heel, the plastic knob, the plastic handle, the depth adjusting nut, the lever, the lever-cam, the cap iron, the plane iron cutter.
Figure
a) Grinding: - The cutting edge of the plane iron or chisel is the part that shaves or cuts the wood material. It is important for the effectiveness of the planing or cutting operation that the plane iron or chisel is properly sharpened. The first stage of sharpening is grinding. Adjust the tool rest of the grinding machine that the cutting edge has an angle of approximately 25 degrees to 30 degrees or twice the thickness of the plane iron or chisel. Press the plane iron or the chisel against the grindstone and held it firmly on the tool rest, while moving the iron from side to side in order to sharpen all parts of the cutting edge. Dip plane iron into water often to prevent burning (blueing) or overheating, because this softens the metal.
For safety, wear safety goggles or use eye shield.
Figure
b) Honing: - It is possible to hone a chisel or plane iron 3-5 times before you have to grind it again - provided you are careful when honing. Produce a honing bevel by raising the back edge of the tool slightly. Move the plane iron or chisel back and forth across the surface of the oilstone. To remove the wire edge which forms, lay the iron flat on the oilstone with the bevel up and move in back and forth a few times. Under no circumstances should you produce a bevel on the flat side of the tool.
Figure
Remove wire edge: lay the iron flat on the oilstone, don't raise the iron to produce a bevel.
Figure
c) Maintenance of plane cap iron: - The cap iron on the plane is there to strengthen the cutting edge and bread the shaving away from the surface thus ensuring a smooth finish. However, if the cap iron does not fit tightly to the cutting iron, shavings may get stuck between the cap iron and the cutting iron clogging up the mouth of the plane and tearing the surface of the work. Carefully file the cap iron to fit against the cutting iron.
Figure
Figure
Tooth cutting tools or saws are main tools for a carpenter. the most commonly used saws by a Carpenter are the Crosscut saw, the Rip saw, the Back saw and the Hack saw.
a) Crosscut saw:
- This saw is designed to cut across the grain of the wood. Its teeth are sharpened like a knife so that they will cut the wood fibres on both sides of the saw cut or kerf. Basically all crosscut hand saws are similar. The main differences are: the length of the blade, the shape of the teeth, the number of teeth per 50 mm.
Figure
- All saws are referred to by their length and the number of teeth points per 50 mm. On some saw the number of saw teeth points is stamped near the heel of the saw blade. A good size crosscut saw for average use by most carpenters on wood framed buildings is a 711 mm 10 - 16 point saw tooth per 50 mm.
Figure
- Cutting action of crosscut saw: the shape of the teeth have a cutting action similar to a series of knifes.
Figure
b) Rip saw:
- This saw is used to cut wood with or along the grain. Rip saws are referred to by their length and number of saw teeth per 50 mm. On some saws the number of teeth points is stamped near the heel of the saw blade. The most common and universal is the 660 mm in length with between 8-12 points per 50 mm. Basically all rip saws are similar, the main differences are: the length of the blade the shape of the teeth, the number of teeth per 50 mm.
Figure
Figure
- Cutting action of rip saw: the shape of the teeth have a cutting action similar to a series of chisels.
Figure
c) Back saw: - The back saw has a metal strip along the back to stiffen the blade. The shorter back saws are occasionally used for close cutting and for precision work. The Back saws range in size from 255 mm - 710 mm and have between 22 and 28 points per 50 mm which makes a very fine and finished cut.
Figure
d) Hacksaw frame/blades: - The hacksaw frame is used with a variety of interchangeable metal cutting blades which are used for cutting soft metals such as copper and aluminium and hard metals such as nails, angle iron and reinforcement steel.
Figure
- There are four chief operations in sharpening a saw: Topping, Shaping, Setting and Filing.
- Topping means to bring the teeth to an uniform height. Place the saw in a vice and run a flat file, held square to the blade, lengthwise until every tooth has been touched. The centre should be a little higher than the ends, if in the length of the saw it shows hollow instead of round, it will "kick" when in use.
Figure
- Shaping the teeth: after a saw is topped, the gullets will be of unequal depth, the teeth will be of unequal size. File the gullets to equal depth, shaping the front and the back of the tooth. Place the file straight across the saw, keeping the file at right angle to the saw blade.
Figure
- Setting: setting of a saw consists in bending over the upper part of each tooth, one to the left and one to the right. The teeth will cut a kerf slightly wider than the thickness of the blade in order to give blade clearance.
Figure
Setting of the saw can be done quite easily with a pistol type saw set.
Figure
- The saw set is used by fitting it over the teeth of the saw and pushing the two handles together. The small shaped steel piece will press the saw tooth onto the shaped wheel or anvil.
Figure
- Procedure for filing a crosscut saw: place the saw in the vice with the handle to the right and the gullets just above the jaws. Commencing from the handle end of the saw, select the first tooth that is pointed towards you. Place the file in the gullet to the left of this tooth and swing the handle of the file about 30 degrees. Take three or four light cuts instead to a heavy one. File in alternate gullets, then reverse the saw and complete the remaining teeth. The bevels on the front and back of each tooth are formed by swinging the handle of the file to the left.
After topping the teeth will have small flat tops. When filing the first side, remove only half the flats, the remainder should be removed when working from the opposite side.
Figure
Figure
- Procedure for filing a rip saw: place the saw in the vice with the handle to the right and the gullets just above the jaws. Commencing from the handle end of the saw, select the first tooth that is pointed towards you. Place the file in the gullet to the left and held the file square across the blade. Take three or four light cuts instead to a heavy one, cutting only on the forward stroke. File in alternate gullets, then reverse the saw and complete the remaining teeth.
Figure
Figure
Workmen - especially those employed in the construction related occupations such as carpenters, shutterers, plumbers, electricians, masons, have to cut or bore holes in wood, metal or concrete using hand operated drills or/and portable electric drills. With the exception of one, the drill has to be fitted with a drill bit which does the boring. The power is provided by the drill.
a) Hand drill: - The hand drill is operated by cranking. This motion turns the boring tool bit) which will penetrate the wood, metal, concrete, etc...
Figure
b) Bit brace: - This tool is designed for use with accessories such as bits, screw drivers, chisels, cinches cutter, countersinks, etc.. It is operated by rotating the middle handle while grasping and pushing the knob handle.
Figure
c) Twist drill: - With centre tip and side cutters 1-10 mm sizes have shanks as per drill diameter. 11 - 15 mm sizes have 13 mm shanks. These drills are used to make holes in wood, metal, fibre, plastic and other materials. Twist drills are used both in hand drills and in power drills. Twist drills are made of different kind of steel:
- a carbon steel twist drill, which is used for boring wood, should not be used to drill holes in hard metals.
- twist drills which are used on hard metals will have HS (high speed) or HSS (high speed steel) stamped on the shank.
- if the shank has no letter markings, it is carbon steel and should be used for drilling material other than hard metal.
Figure
d) Auger bit: - The Auger bit has a solid centre and can be used with a brace or electric drill. Bits are available in dimensions - 6 mm to 25 mm. The sizes are found on the shank of the bit.
Figure
e) Expansion bit: - This type bit is designed in such a way that it can be adjusted to the bore holes of different diameters such as 15.8 to 45.00 mm.
Figure
f) Countersink bit: - This bit is used to increase the diameter of the top of a drilled hole in order to receive the head of a screw. It is conical in shape. The deeper the countersink is allowed to penetrate, the greater will be the diameter of the hole.
Figure
g) Doorlock bit: - This bit is used primarily for fitting cylinder locks. It can also be used to bore holes for pipes and conduit. Sizes are available to meet most common job requirements.
Figure
a) Claw hammer: - Claw hammer are used by carpenters principally for the driving in of nails to connect timber together. The claw part of the hammer is used to grip nails and to remove them from the timber. Claw hammers have wooden, steel or fibreglass handles. Claw hammers with steel or fibreglass handles are fitted with a rubber or vinyl hand grip. This type of handle is less likely to break under normal use.
Figure
b) Screwdriver: - A screwdriver is used for driving screws. Screwdrivers are of various shape and sizes according to the work they are required to do. There are two types of screwdrivers. They are named Flat head screwdriver and Phillips screwdriver.
Figure
c) Nail Punch: - These are used for punching or "setting" the head of the nail below the surface of the timber. They are made in various sizes to suit the particular size nail being driven, they have a concave point to seat on the head of the nail.
Figure
d) Crow Bar or Pinch bar: - These bars are commonly used on building sites to remove formwork and nails. They are also used to move or position heavy construction items.
Figure
e) Tower Pincer: - These are used for the withdrawal of nails or brads, the pinching off of the points or heads of nails or for holding small metal parts while work is performed upon them.
Figure
a) String: - A string is used to get a straight line.
Figure
b) Line level: - This is a short (about 75 or 100 mm) and very light level and is used in conjunction with the line above being hung on it by means of hooks at each end of the level. It is used to test the approximate levelness of height lines in foundations and care must be taken to see that it is hung exactly in the centre of the line, otherwise there will be an unequal sag in the line with consequent inaccuracy reading on the level.
Figure
c) Plumb Bob: - A plumb bob is a metal weight with a string attached to a central hole. This instrument is used-to check the plumbness of vertical surfaces.
Figure
d) Spirit level: - The spirit level is a tool which is made of wood or lightweight metal. Spirit levels have at least two vials. One is used for levelling vertical surfaces, and one is used for levelling horizontal surfaces.
Figure
e) 3-4-5- method or builders square:
- Usually this method is used on the building site to prove the squareness of the corners, during the process of making the foundation. It acts like a big try square.
Figure
- Sometimes on the building site the 3-4-5 method is too small and you have to chose bigger distances. That would 6-8-10. On the other hand if the 3-4-5 method is too big you use the 1.5-2-2.5 method.
Figure
f) Water level: - The water level consists of a transparent hose and at the end plastic or glass pipes are fixed. Because still water is always level the surface of the water in the plastic or glass pipe is always level.
Figure
g) Straightedge: - length of timber with parallel, straight edges are used for testing the straightness of other timbers, etc..
Figure
a) Brick trowel: - This is the most important tool as it is constantly in use when spreading mortar and laying bricks. The brick trowel may also be used for roughly cutting bricks. To do this, nick the two edges of the brick in the required position with the trowel and then give it a sharp blow.
Figure
b) Brick Hammer: - The brick hammer is used for breaking, splitting, shaping and trimming masonry building units.
Figure
c) Jointer: - Jointer are used for finishing the exposed cross mortar joints between masonry units. Finished joints are required in order to seal the joint against moisture and present a pleasend appearance on the faced wall.
Figure
d) Runners: - Runners are used for the same purpose as jointers except that runners are used for finishing the parallel mortar joints.
Figure
e) Brick set: - It is a type of chisel, designed for cutting bricks.
The set is used in conjunction with the club hammer.
Figure
f) Club Hammer: - Club hammers are used for striking the brick set.
Figure
a) Float: - It is used for floating concrete.
Figure
b) Edger: - An edger is used breaking off sharp concrete edges while the concrete is firm but still moist.
Figure
c) Groover: - A groover is used for making the control joints in large concrete slabs.
Figure
d) Showel: - Is used for shifting earth, sand, gravel etc...
Figure
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