What is linear measurement?A system for measuring lengthMeasuring devices, also called layout tools, are used to measure length.Examples of tools used: rules, squares, scratch awls, calipers, measuring tapes and dividersPhoto courtesy of Snap-on Tools.

Purpose of linear measurements:Measure and mark materials before cutting or shapingConstruct a project from a patternCreate your own patternLay out a project

Materials for measuring devices SteelDurable lines and numbers stay visible for a long timeBends without breakingWithstands rough useFirst choice of material for calipers, dividers and other slender tools that must measure very accurately and not bend easily

Materials for measuring devices (cont.) Aluminum2nd choice for many layout toolsTough, lightweight and durableWoodCheap, soft and lightweightBreaks easily, absorbs moistureDoes not wear wellPopular for the wooden folding rule

Materials for measuring devices (cont.) PlasticTough and lightweightMelts if touches hot object or flameMay be damaged by solventsLimited useClothUsed for some 50-foot tapesCheap and lightweightNot very accurate stretches under stress

Cost vs. quality Cheap tools are seldom a bargain.Cheap tools are likely to be inaccurate and unsatisfactory after very little use. Good tools may seem expensive, but last a lifetime with proper use.Good tools allow skilled labor and craft.Even a skilled worker cannot do good work with poor tools.

English/U.S. customary system of measurements Uses inch, foot, yard, rod and mileINCH traditional U.S. unit for woodworking and metalworking

Metric system of measurement Used for scientific work in the U.S.Increasingly used for nonscientific use.Many layout tools use both metric and U.S. customary markings.Based on multiples of tenEasy to use without fractions

Common tools for linear measurements:Tapes, rules and scalesLast number on the scale is read plus any fraction

Measuring tape:Flexible measuring device that rolls into a case.Several feet to hundreds of feetSteel, cloth or fiberOften self-retracting with locks or buttonsUsually has end hookEasily broken handle with care

Photo courtesy of Snap-on Tools.

Folding rule:Rigid rule2-8 feet in lengthFoldable for easy handling and storageInsert for easy inside measurementsWood, plastic or metalTake care when opening and closing

Scale:In this use, refers to rigid steel or metal measuring device1-3 feet in length, to 1 in widthWooden scales sometimes called bench rules about thickMetal scales are relatively thin, accurateHandy in the shop, not used much otherwise

Why use squares, levels and lines?Measuring angles and cutting accurately are essential for the success of any construction project.Squares, levels and lines are all tools that are used to guide the builder, where a particular angle or a level measurement is needed.

Essential measuring and cutting tools: Squares draw angles for cutting and check cuts for accuracyLevels determine if an object has the same height at two or more pointsLine thin material stretched tightly between two or more points

More about squares:Used to draw angles for cutting and to check the cuts for accuracyMost commonly used squares:Framing squareTry squareCombination squareSliding T bevel, also called a bevel square

The framing square:Flat square with a body and tongue Usually made of steelAlso called a carpenter's square and a steel squareMay contain tables to calculate board feet and raftersHas both inside and outside measurements16 wide

The try square:Used to try or test accuracy of cutsUsed to mark lines on boards before cuttingSteel blades with wood, steel or plastic handlesGood for marking boards up to 12Used to draw 90 or 45 lines on boards

Combination square:Combines many toolsBubble for levelingBubble for plumbingDepth gaugeRemovable blade for steel scaleUse for square and for 45 angleMost commonly used square

Sliding T bevelDevice to lay out anglesAlso called bevel squareA bevel is a sloping edge as when a corner edge is cut away from a board

Using a spirit level:Determine if an object has the same height at two or more pointsContains alcohol in a sealed, curved tube with a small air space or bubbleMounting is wood or aluminumBubble between 2 lines when both ends are evenCrossways mounted tube can be used to plumb an object

Using a line level:Attached to a string or line stretched between two distant pointsWhen the string is pulled tight, the level indicates when both ends are the same height.Useful for leveling the corners when building with block and for setting stakes to gauge the depth of concrete.

Laser beam level:Directs a strong beam of light across a spaceLevel mark can be made at several points and at varying distancesUseful in laying out houses and other buildings

Using lines:Strong cotton or nylon lineFor block, flooring, cutting rafters, ceiling tiles, etc.Chalk line cord with chalk leaves trailPlumb line string with round and pointed metal plumb bob attached which hangs in perfect vertical line

Using a square to mark a board:Measure and mark the desired length.Place handle firmly against board edge.Move the blade against the mark.Draw a line across the board.

Squaring a large area:Even 1 error can cause serious problems on large construction jobMeasure 90 angle by creating a right triangle with sides that are 3, 4 and 5.Determine if a rectangle is square by measuring the diagonals. Both must be equal.

Parts of a portable electric drill:A portable power drill is a small tool run by an electric motor that can be easily moved to the work. Power cord Handle Motor housing Gear chuck Vents Trigger switch Trigger switch lock Reversing switch Chuck key or wrench

Classifying drills:Chuck Size (the device that holds a drill or tool bit in the machine): commonly 1/4, 3/8, 1/2Power Rating: typically from 2 to 5 amperes. A 115-volt motor using 5 amperes equals about horsepower and is considered powerful for a portable drill.Duty Cycle: the amount of time a motor can run versus the time it needs to cool off. Continuous duty drills can be used all the time for 6-8 hrs.

Types of drills:Variable Speed: motor speed can be controlled by the operator

Reversible Drills: can run backward and forwardPhoto courtesy Snap-on Tools.

Types of drills:Hammer Drills: will turn a bit and also provide rapid striking action useful for masonry materialsCordless Drills: contain a rechargeable battery pack

Photos courtesy Snap-on Tools.

Uses for drills:Drilling holesTurning screws in and outDrilling holes in brick, block or stoneMaking holesSanding and polishing

Recommended procedures:Use only straight shank bits. When tightening a drill chuck, place the key into the hole and tighten the chuck securely. Place the key into a second hole and, again, tighten securely. Center punch metal to help start a drill bit. Always make sure the drill bit is sharp. Hold materials to be drilled in a vise or other secure device.Use slow-turning drills for large bits.

Recommended procedures:Use even pressure on the drill. Ease off the pressure when the drill is breaking through the material. Hold the drill so as to avoid binding the drill bit. Position yourself so that balance is always maintained; never lean on a drill. Remove the drill bit from the chuck when finished. Store the portable power drill in its own case or in a special storage rack.

Pilot holes:For large holes, a pilot hole is used a small hole drilled in material to guide the center point of larger drills.Pilot holes are also used when installing screws to prevent splitting the wood. If a drill bit is not cutting, check to see if the reverse switch is on. If the drill is turning clockwise and not cutting, the drill bit is dull and must be sharpened.

Ag Engineering Library

So whats the big deal about hand tools?Have been around for centuriesCan create very high quality projectsRequire more skill than power toolsGenerally safer than power toolsSafety procedures requiredHigh quality hand tools may be more expensive than power tools.

Advantages to hand tools:Can be used without electricitySometimes more appropriate than power toolsNo set-up needed

Classifying hand tools:No power required use simple machine principles like inclined planes, wheel and axle, levels and fulcrumsMay be named for user (carpenter, mason, machinist, mechanic)Use or function (layout, cutting, boring, driving, holding, turning)

Layout tools:Measure or mark wood, metal and other materials before cutting or shapingExamples: rulers, squares, scratch awls, gauges, calipers, measuring tapes and dividersEnsure correct length, width, thickness and/or shape An example of hand tools that are not generally replaced by power tools

Layout tools examples:Photos courtesy of Snap-on Tools.

Cutting tools:Chop, cut, saw or otherwise remove materialPermit user to shape materialExamples: saws, chisels, hatchets and knives Sharp edge must be kept keen.Cutting edges are usually made of high carbon steel, tungsten or carbide. Photo courtesy of Snap-on Tools.

Handsaws:Cut across boards or rip boards and panelsCrosscut means to cut across the grain; Rip means to cut along the length of the board or with the grain. Teeth determine use.Filed to a point = cut across the grain of boards (crosscut saws) Filed to a knifelike edge = cut with the grain (ripsaws)

More details on handsaws:Length from 20 to 28 inchesShorter saws for smaller peopleShorter saws for finer cuts use finer teethTeeth range from 6 to 14/inchBacksaw is mounted in box or frame to cut precise anglesCoping saw used to cut curves in wood

Handsaw details:

Boring tools:Make, size or shape holesExamples: drills, bits, reams and the devices used to turn themSharp cutting edge must be maintainedVariety of shapes, sizes and types

Driving tools:Used to move another tool or object such as a nail, a punch or a chiselExamples: mallets, hammers and sledges.Size and type depend on intended useClaw hammers 2 types (curved and ripping) are used to pry wood apart and to extract nails. Rubber and plastic mallets are used for moving wood and other materials without marring the surface.

Hammers and mallets:

Holding tools:Used to grip wood, metal or plasticUsed as an aid while other tools are used to cut, shape, modify or fasten the material being heldExamples: clamps, pliers and vises

Holding tools examples:Photos courtesy of Snap-on Tools.

Turning tools:Used to turn nuts, bolts or screwsExamples: wrenches, sockets and drivers, and screwdriversOften used to install a fastener in wood or other materialVariety of types and sizesSize depends on the amount of torque (twisting power) needed. Those with longer handles or longer in reach usually provide more torque. This uses the principle of a lever.

Turning tools examples:Photos courtesy of Snap-on Tools.

Rust is a big problem!A chemical reaction when moisture meets metals containing ironRust is also called ferric oxide.Rust is corrosive eats away metals containing iron

Problems caused by rust Can destroy toolsPrevents efficient tool useParts like bolts can freeze together so they must be cut off.

Possible solutions for rust problems Dissolve rust with penetrating oilApply heat from a torch to loosen rusty partsCut off rusty bolt with a cold chisel

Watch out for rust on Stationary toolsTable sawsPlanersJoinersShapersBand sawsCast iron beds can stain and mark wood and will not slide easily.

Its a matter of degree Light surface rustReddish brown to black specksIf left unattended will become seriousBest stage for rust removalAdvancing rustLarge red or brown surface spotsProgression of light surface rust

Getting more serious Complete rustSolid reddish brown over entire surfaceSerious damageScaly rustCompletely covers surfaceComes off in scales if rubbedPitted surface and serious damage has advanced

Now youre really in trouble Complete rust-throughHoles appear in the metalAlmost beyond repair

Removing rust Light rust use fine steel wool dipped in light oilPitted surface wire brush, , wire wheel, steel wool, emery cloth or aluminum oxide paper

NOTE: Pitting is a sign of permanent damage and should be avoided!

Getting rid of rust Use a wire brush for tools like shovelsApply the wire brush to the surface.Brush off the loosened rust.Continue until all rust is removed.Use a wire wheel for tools and boltsMount on stationary power grinderUse a wire wheel for larger surfacesMount on portable grinder

Finishing off the rust removal:Use 400-grit silicon carbide paper.Add light oil to the paper for a very smooth surface.Dry metal thoroughly.Coat all smooth metal surfaces with light oil.Use heavier oil for rougher surface.

Dont leave oil on some surfaces Beds of stationary power woodworking toolsOil will contaminate wood.Use a high-quality paste wax on the surface instead.

Steps to treating a stationary power tool bed:Clean machine bed of all rust.Use fine steel wool or 400-grit paper.Wipe away loosened rust.Apply wax in circular motion.Allow wax to dry to a haze.Buff wax with soft cloth.Apply a new coat after each use.

Protecting surfaces Prevent moisture from contacting iron by using a coating of oil or wax.Protecting toolsKeep in a dry placeCoat with oil or waxEnclosed building for storage, not open shedPrimers and paintsRemove rust, then prime and paint

Wooden handles are found on common tools:AxesHoesShovelsPosthole diggersHammersPicks

Pros and cons of wood:Advantages:ComfortableAbsorbs shock wellLightweightDisadvantages:Can decayCan breakWooden handles can be replaced!

How wooden handles are attached Held in place with a wedgeHole in head of the tool is called the eyeEye is smaller on the side where the handle enters than on the opposite sideOnce inserted, the handle can be wedged to fill the holeImproper fit is ineffective and dangerous

Removing a broken handle:Place the head securely in a vise.Use 1/4 or 3/8 metal cutting bit to drill numerous holes in the wooden core.Drive the remaining wood out of the head using a large punch.

Replacement handles for hammers and axes:Buy the correct size.The end of the handle that goes into the eye of the tool should be longer than the eye is deep and have the same shape as the eye.It should also be slightly larger in cross section than the eye.Make the handle fit exactly by placing it in a vise and shaping the end of the handle that is to be inserted into the eye.

Attaching a hammer or axe handle:Place the head against the end of the handle to see if it will start on. Observe where wood must be removed to shape the handle to enter the head. Use a wood rasp or coarse file to shape the handle. Try the head frequently as wood is removed to avoid a loose fit.

Attaching a hammer or axe handle (cont.):Work the handle down until the head slides on snugly. It should come to rest about 1/2" from the enlarged part of the handle. Mark the handle on both sides of the head. Remove the head. Reposition the handle vertically in the vise. Place the head against the end of the handle to see if it will start on.

Attaching a hammer or axe handle (cont.):Use a handsaw to make a kerf across the longest center line of the handle. The kerf should extend two-thirds of the distance between the two marks in step 6. Reposition the handle in the vise and squeeze the end until the saw kerf is completely closed. Run the saw down through the kerf again. When released, the kerf will be wider at the end than farther down the handle.

Attaching a hammer or axe handle (cont.):Make a wooden wedge as wide as the oval hole in the head and thick enough to spread the handle when driven in. Slide the handle in and drive it in securely with a plastic, leather, rubber or wooden mallet. (Steel hammers can ruin wooden handles.)Grip the handle with the vise just below the head.

Attaching a hammer or axe handle (cont.):Use a hacksaw to saw off the excess handle flush with the head. Drive the wooden wedge so the handle spreads and fills the head.Use a hacksaw to saw off the excess wooden wedge. Drive one or two metal wedges in at right angles to the wooden wedge to hold the wedge in place.

Attaching a hammer or axe handle (cont.):Place the tool, head down, into a metal or plastic container about the size of the head. Add several inches of boiled linseed oil and brush oil around the handle and head. The handle and head should soak in the oil several days to seal the wood. Remove the tool, rub oil on all parts of the handle, dry and polish.

Attaching handles to rakes, hoes and forks Rakes, hoes and forks are driven into their handles.The handles have metal collars called ferrules.The tool has a metal finger called a tang which is driven into the ferrule.

Attaching handles to shovels:A metal tube extends up the handle for extra support.Handles are made to fit specific shovels.

How to attach a shovel handle:Grind off the head of the rivet that holds the handle. Remove the rivet with a drift punch. Spread the metal tube and drive out the remains of the old handle. Use a mallet to drive the new handle securely into place.

How to attach a shovel handle (cont.):Use a vise to close the metal around the handle and secure the assembly while drilling. Insert a drill through the hole in the metal and drill through the wooden handle. Install the replacement rivet securely, being careful to keep the metal tight to the wood.

Ag Engineering Library

Types of portable sanders:Belt sander used for coarse sandingDisc sander used for coarse sandingFinishing sander used for final sanding before finish is appliedPower sanders serve the same functions as hand sanding, but are much faster.Power sanding can create a smooth finish on wood or metal if done correctly.

Effective sanding Sanding with the grain for fine workCrossgrain sanding for uneven boards, very rough boards or to remove difficult finishesStarts with coarse sandpaper, then medium and ends with fineBelt or disc sander can be used for rapid work followed by a finishing sander or hand sanding.

More about finishing sanders:They move randomly, so sanding can be done with the grain or across the grain.Almost all finishing sanders are orbital sanders, moving in a random circular pattern that results in a faster cut, but gives a fine finish.

Photo courtesy Snap-on Tools.

Main parts of a belt sander:The belt sander has a moving sanding belt.1. Motor housing 2. Handles 3. Belt 4. Belt rollers 5. Belt adjustment 6. Trigger switch 7. Switch lock 8. Power cord 9. Dust bag

Safely operating a belt sander:Wear suitable face protection and protective clothing. Check the power cord and extension cords for safety. Install a sanding belt of suitable coarseness. Lay the sander on its side when not in use. Be sure the dust bag is empty or nearly so before starting to sand. Make sure the wood to be sanded is secured on the table.

Safely operating a belt sander:Always start the machine while holding it slightly above the material. Keep the power cord out of the way of the belt. After turning on the sander, touch the work with the front part of the belt first, then slowly settle the rest of the belt down onto the work. Operate the machine with two hands at all times.

Safely operating a belt sander:Sand with the grain. Move the machine from one end of the board to the other in a straight path; then move it slightly sideways and draw the machine back over the new area. Gradually work across the board by slightly overlapping the forward and backward passes. Keep the machine in motion, letting the weight of the sander do the work without applying pressure.The final movement is to lift the machine off the work while it is still running.

Safely operating a belt sander:Examine the work carefully. Resand if necessary to create a smooth, perfectly level surface. Install a fine sanding belt and resand. This resanding leaves the work in its smoothest possible form using a belt sander. Use a finishing sander or hand sander to obtain the degree of fineness desired.

Parts of portable disc sanders/grinders:Some tools are designed to be used as either sanders or grinders by simply changing out the sanding disc or grinding wheel. 1. Motor housing 2. Handles 3. Power cord 4. Switch or trigger 5. Switch lock 6. Cooling vents 7. Wheel 8. Spindle 9. Safety guard 10. Tool rest

More on sanders and grinders:Disc sanders:Use grit on a flexible revolving plateAluminum oxide discs may be used for sanding wood or metal.Discs made from flint paper are only suitable for wood sanding. Grinders:Use rigid grinding wheelsOnly used for metal Used to shape metal, grind down welds, and remove metal as neededWire brushes may also be turned by grinders to clean metal.

Examples of sanders and grinders:Disc sander:Grinder:

Photos courtesy Snap-on Tools.

Safety precautions when using a grinder:Wear a face shield. Check the grinding wheel for cracks or damage and do not use a damaged wheel. Use wheels that are designed for the machine. Tighten the wheel securely and carefully. Never use a grinding wheel that is less than one-half its original diameter. Secure small pieces in a vise, if possible.

Safety precautions when using a grinder (cont.):Do not grind metal in areas with combustible gases or materials. Hold the machine with both hands at all times. Do not discharge sparks against persons, clothing, or other combustible materials.

Sander or grinder procedures:Select the correct sanding disc, grinding wheel or wire brush. Install the appropriate guard. Wear appropriate face protection and protective clothing. Be sure the work is properly secured. Keep power cord out of the way. Grip the machine firmly with both hands and turn on the switch. Settle the turning sanding disc, grinding wheel, or wire brush onto the work slowly.

Sander or grinder procedures (continued):Touch the work gently with the wheel to avoid the wheel catching the work and throwing metal particles. Do not apply pressure to the machine. After turning the switch off, do not lay the machine down until it has completely stopped. Do not lay the machine down on its disc or wheel. Remove the grinding wheel or sanding disc and store the machine properly after use.

Parts of a finishing sander:1. Motor housing 2. Handles 3. Switch 4. Switch lock 5. Power cord 6. Paper clamps 7. Pad 8. Sandpaper

Procedures for using a finishing sander Use appropriate face and body protection. Check sander to determine if it is a straight line or orbital type.With rough work, use coarse sandpaper first, then medium, then fine sandpaper. Use precut paper or cut to fit the machine. Install sandpaper.Apply only slight pressure and keep it in constant motion. Remove dust frequentlyStore the machine properly when finished.

Describe and Select Fasteners

A fastener is Any device used to hold 2 or more pieces of material together in placeCommon agricultural mechanics fasteners:NailsScrewsBolts with nuts or washersMachine screws

What is a nail?A fastener driven into the material it holdsLong stem part = shankEnlarged top = headClassified by use or formVaries in shank thickness and head diameter according to useSoft material needs a large headHeavy material needs a thick, strong shank

Nails and hammers meant for each other Nails are driven in by a hammer.Small nails can be pulled out by the claws of a hammer.Larger nails must be removed with a crowbar or nail puller.Long nails may need a block under the puller to provide a fulcrum.

Common nails/uses:Staple wire fence construction Hinge fasten hinges on doors and cabinets Plasterboard attach plasterboard to studs Roofing nail rolled roofing and shingles Lead head nail galvanized steel roofing/siding Cut nail tongue-and-groove flooringFinishing interior finish work, cabinetsBox light construction, siding, end grain of boards Common general construction, sheetingDuplex concrete forms, insulators

Types of nails:

Measuring nail length Lengths of common nails is by the penny, and symbol d.Some common sizes:Box nails: from 2d to 40dFinishing nails: from 2d to 20dCut nails: from 2d to 20dSpikes: from 12d to 12 inches

Improved nails are modified for a specific job Soft insulating boards need nails with large square headsThread nails part is threaded for more holding powerHeat treated for hard substancesZinc treated to prevent moistureAluminum for nailing aluminum

Improved nails:

What is a screw?A fastener with threads that bite into the material it fastensUsed in wood, metal, plasticPilot hole is predrilledScrews generally cut into the material as they are turned.

Common kinds of screws:Wood threads cut into wood fibersSheet metal wider threadsCap screws thread into thick metal with matching threadsLag screws very coarse threads for structural timbersDrywall thin shank and tough steelDeck long screws for outside decks

Kinds of metal used Steel screws may be coated with a blued, galvanized, cadmium, nickel, chromium or brass finish.Solid brass screws are rustproof and used where severe moisture problems destroy coated or plated screws.

Screws are classified by type of head Flat head: tapered heads fit flush with surfaceRound and oval head: rounded heads with slotPan head: upside-down frying pan look/used for sheet metalLag screws: unslotted square (4 sides) or hex (6 sides) heads and turned with wrench

Tools used to turn screws:Standard screwdriver used for slotted head screwsPhillips screwdriver shaped like a plus signSix-sided, hex or Allen wrench used to turn Allen screwsPower drill or power driver screws with star- or square-shaped holes

Measuring screw sizes:Specified by diameter and length of shankDiameter from 2 through 24Diameters 6, 8 and 10 are commonCommon lengths from to 4

What is a bolt?A fastener with a threaded nutCommon bolts used in ag mechanics: machine bolts, carriage bolts, stove bolts, plow bolts, and special boltsThreads in two types coarse (UNC) and fine (UNF)Standard and metric sizesMost automotive engine bolts are fine threaded. Carriage bolt is used with wood; has a round head over square shoulders

Types of bolts:

What is a nut?A device with a threaded holeMovable parts of boltsSquare (4 sides) or hex (6 sides)Wing nuts have extensions for tighteningSpecial nuts with slots allow cotter pinsGraded by strength

What is a washer?Flat device with a hole in the centerUsed as part of a fastenerFlat washers prevent bolt heads or nuts from penetrating material.Special lock washers prevent nuts or bolts from loosening due to vibration and use.

Develop and Follow Plans:Pressure Treated Lumber

Why treat lumber?Outdoor conditions can harm wood.SunshineMoistureBacteria and other organisms attack wood and decay sets in.Untreated pine touching moist ground may only last 1-2 years.

Pressure-treated lumber:Chemicals are driven into the wood under pressure.Chemicals prevent wood decay and insect damage.

How the process works:Lumber is immersed in preservative.Treated lumber is pressurized.Pressure forces the preservative to penetrate the lumber.

Most common chemicals used as wood preservatives:Creosote Pentachlorophenol Acid Copper Chromate (ACC) Ammoniacal Copper Arsenate (ACA) Chromated Copper Arsenate (CCA)

CCA is #1 chemical used CCA is Chromated Copper ArsenateBinds to wood fibersCCA-treated wood lasts for decades even if wood is in contact with moisture, bacteria and organisms in the ground.

CAUTION!!These chemicals are harmful or toxic to plants and animalsBe careful when choosing pressure-treated lumber for agricultural settings.

Choose the correct pressure-treated lumber for the job Ground useCan contact the ground and is decay-resistant

Above Ground UseShould not contact the ground

The American Wood Preservers Bureau label includes:Year of chemical treatment The preservatives used in treating the lumber Trademark of bureau supervising the treatment plant Proper exposure conditions Treating company's location Dry or KDAT if applicable

Safety observations Wear gloves when handling pressure-treated lumber.Chemicals are toxic.Splinters can penetrate the skin of your hand. Avoid breathing sawdust. Do not burn pressure-treated lumber puts toxic chemicals into the air.

Selecting and Using Abrasives

What is the purpose of abrasives in woodworking?To prepare wood for finishing with stains and clear coatingsWood must be very smooth to accept a quality finish.Usually called sanding, although true sand is no longer usedTo remove fine marks from planning or millingRemove imperfectionsRemove saw marks

3 types of abrasives used in finishing wood:Abrasive paper Steel wool Rubbing compounds

Getting down to the nitty gritty:Grit refers to size of the particles on the paper that remove woodSmaller numbers = coarser grit and faster removalLarger numbers = finer grit and slower removalCoarse (40-80) to fine (400, 600, 1,000)Steel wool ranges from 0 (very coarse) to 0000 (very fine) threads of spun steel

Types of abrasive paper Note: sand is no longer usedCan be purchased in sheets or rollsFlint paper low cost, wears out quicklyGarnet paper durable and low cost, but cannot use wetEmery paper durable, fine grits, expensive, cant use wet

More types of abrasivepaper Emery cloth like emery paper but backed with cloth, can be used wet, used on metalAluminum oxide paper fast-cutting, long-lasting, used with machine sanders, expensiveSilicone carbide paper durable, can be used wet, very fine grits, inexpensive

Using abrasive papers:Sanding lumber after planing:Sand the first time using a 100 to 120 grit to remove any planing or milling marks.Sand all marks from sawingSand in the direction of the grain of the wood.After assembly:Sand before applying finishSome spots may need sanding before assembly

Sanding by hand:Sanding block prevents gouging irregularities into the woodPurchase or make blocks from woodMost comfortable are flexible, rubberlikeSanding padsThick foam, plastic or other flexible backingEasily sand contours in wood

Hand sanding techniques:Use progressively finer abrasiveSwitch to finer grade when wood is smoothOne grade finer until you reach 220 gritVacuum when sanding is complete.Use a tack cloth to pick up final dust.

Using steel wool:Composed of finely spun fibers of steelUsually used with paint and varnish remover to strip before refinishingCan leave fine particles hard to removeVery fine steel wool sometimes used between coats of varnish or other finish

Rubbing compounds:Usually made from finely ground pumice stoneComes as a fine powder to be mixed with water or oil or already mixed in a waxlike compoundUsed to smooth out irregularities in the final finish to give a very smooth, glassy final finish. Used with a hard finish such as lacquer or with well-cured polyurethane finishesRubbed into the surface with a soft cloth until the surface is smoothWiped off at the end

Selecting and Using Plywoods

What is plywood?A wood product made of veneers (thin sheets of wood) glued togetherLayers of veneer are glued perpendicular to each other (at 90 degree angles).

How is plywood made?Veneer logs are carefully selected and cut to the proper length.A log is softened with steam and mounted on a lathe.A knife peels off a thin layer of wood in continuous veneer sheets.As many as 5-6 layers are glued.The glued stack is heated under pressure.

Who uses plywood?Plywood was discovered by Egyptians, Romans and Chinese.Strength is added by perpendicular placement of layers.Construction uses:SubfloorWall sheathingRoof sheathingFurniture

Kinds of plywoodGrading is done by:Quality of exterior layersGlue's ability to tolerate moisture Classified into 2 grades:INTERIOR: Glue holding the veneer layers together weakens when it becomes wet.EXTERIOR: Glue can withstand dampness and can remain strong and usable when exposed to weather.

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Classified by quality of veneers:Both outside letters are given a letter grade.The higher the letter, the better the gradeFor example: sheet graded as ADTop side graded A is smooth and paintable.Bottom side graded D has knots and knotholes up to 2 across the grain.

How the veneer gradesstack up:Grade A: paintable, can be used for natural finishes, synthetic repairs are permitted. No more than 18 neatly made repairs. A synthetic repair uses wood filler as opposed to a wood patch. Grade B: solid surface with impurities shims, circular repair plugs and tight knots up to 1" across grain. Synthetic repairs and minor splits permitted.

How the veneer gradesstack up (cont.):Grade C plugged: improved C grade veneer. Splits limited to 1/8" and knotholes limited to 1/4" X 1/2". Synthetic repairs permitted.Grade C: Tight knots up to 1 1/2" and synthetic or wood repairs permitted. Discoloration or sanding defects, which do not impair strength, are permitted, and limited splits are allowed. Grade D: Knots and knotholes up to 2 1/2" across grain and 1/2" larger within specified areas. Stitching permitted, limited splits allowed, limited to interior use and exposure 1 and 2 panels.

How plywood is sold:4 x 8 sheetsCommon plywood thicknesses:3/85/81

American Plywood Association labels include Panel gradeSpan ratingThicknessSquare or tongue-and-groove edgeCode of recognition of the APAExposure durabilityMill numberAPAs performance-rated panel standard

APS plywood label

Using Different Types of Stainsand Finishes

How are stains and clear finishes used?StainsColor wood to different shadesHighlight the wood grainClear finishesProtect woodAllow the beauty of the wood to show through

More about stains Stains penetrate wood and can highlight the wood grain.Water-based stains are easier to clean up.Oil-based stains penetrate more deeply and bring out the grain of the wood.Apply to bare wood.Prepare wood with very fine grit sandpaper.Carefully remove all dust.

Applying stain:Apply with lint-free cloth or clean brush.Make sure all parts are covered.Let it stand for about five minutes.Use a soft, lint-free cloth to remove the excess stain.A clean, dry brush can be used to remove excess stain from cracksKeep wiping until the stain is even.If blotchy, wipe with a cloth dipped in mineral spirits and begin again.

After the first coat:Let the stain set overnight.Fine wood fibers will stand up called raising the grain. Lightly sand with 220 grit sandpaper and use a tack cloth to pick up all dust.Apply a second coat of stain and let dry overnight.

Fillers Woods like oak, walnut and mahogany have what is known as an open grain.Large surface poresWood filler may be needed for smooth finishThe filler may contain stain or dry clearWipe on with a clothLet dry overnightSand lightlyApply finish

5 types of clear finish common on wood:Oil finishVarnishPolyurethaneEpoxyLacquer

Basics on clear finishes:Use on bare wood or over stain.Follow instructions if combining products.Usually okay to combine water- and oil-based finishes.Prepare wood first and remove dust.Apply finish in a dust-free environment.

Oil finishes:Bended oils like linseed oil or tung oilRubbed into wood with clothDoes not contain hardeners like varnish doesGenerously applied to bare wood and allowed to soak inRemove excess with a soft, clean cloth.Dry overnight and sand lightly with 220 grit paper.Remove dust and apply more oil.Several coats are needed.

Pluses and minuses of oil finishes:Advantages: Penetrate the wood and become a part of the woodDeep, rich-looking finishDisadvantages:Tend to become dark over timeNot as durable as other finishesTend to dry out over time

CAUTION: Discard all oily rags in an approved container to prevent spontaneous combustion.

Varnish:Made from a variety of different natural oils, often linseed oil and tung oilHardeners are added to seal wood and repel moisture.Comes from plant sources linseed oil from flax seeds, tung oil from the nuts of the tung tree.Does not adhere well to bare wood, so requires a sealerSpar varnish is water resistantApplied with a natural bristle brushNeeds two coats

The good and bad side of varnishes:Advantages:Easy to useBrush on or apply with a wool applicatorDisadvantages:Darken with ageMay become softNot as durable as some of the newer finishes

Polyurethane finishes:Composed of synthetic materialsClear, durable and resistant to waterSome types can be used outside and may even be resistant to such solvents as alcohol.Used extensively on wood floors. Applied like varnish except Applied directly to bare wood or over stainCertain types may be rubbed on with a cloth.

How polyurethane finishes stack up:Advantages:Easy to applyGoes on smooth with brush or soft clothDurableLong-lasting finishDisadvantages:Can be expensiveDifficult to removeBrushed finish can have a heavy, shiny appearance that looks like plasticNewer wipe-on types look better

Epoxy finishes:Most durable of all of the clear wood finishesUsed by mixing two parts just before it is appliedBrushed on

Using epoxy finishes:Advantages:Flexible Resists abrasion, solvents, chemicals, water and heatDisadvantages:ExpensiveDifficult to applyAppearance not as high quality as some other clear finishes

Lacquer:Most often applied with a spray gun Newer types of lacquer may be applied with a brushDries almost instantlyHard, durable finish

Do you lacquer or not?Advantages:Dries so quickly that several coats can be applied in a single dayCan be rubbed smooth with rubbing compoundProvides a hard, durable finishDisadvantages:Spray equipment is expensive.Equipment must be cleaned after use.Finish may be marred by water.

Woodworking and Construction Careers

Would I enjoy a forestry orwood products career?Many foresters have a natural interest in conservation and the environment.Forests are multiuse: timber, wildlife and recreation.Silviculture studies the development, cultivation and reproduction of forest trees.Wood products technology improves and develops new wood products.

A challenging career ...Forests and woodlands make up 1/3 of U.S. land areaIndividuals own 58%Forest products companies own 14%Balance is state and national forests

Forests provide:Essential commodities like:Lumber, veneer, wood panelsWood pulp, paperCellulose, chemicalsRecreation and scenic areasHome for wildlifeCleaner air and waterSoil conservation

Forests are arenewable resource.It will take work and knowledge to use and maintain forests for future generations.Demand for wood products on the increase1.6 billion trees must be replanted yearlyMost replanting by industry and private owners

Where could I workin a forestry career?In the forestMills, offices, laboratoriesClassrooms, board roomsLegislaturesLaboratories

Employment in the timber industry:Planting treesTree nurseriesMarking trees for harvestPurchasing or marketing timber

Employment in construction, furniture, packaging or paper:Technical, management, marketingResearchManufacturing adhesives, chemicals, plasticsWood machinery and equipmentPrefabricated wood products, plywood and veneer

Federal employment:U.S. Forest ServiceNational Park ServiceBureau of Land ManagementSupervise recreation, conservation, watershedsAdminister timber sales and leases

Other employment:State extension serviceForestry associationsCounty and municipal governments

What training will I need?Foresters generally have at least a 2-year degreeBachelor's degree helpful for a professional or management positionMaster's or Ph.D. for research or teaching

Unit 1:Woodworking Identifying Types and Grades of Lumber

Board Feet (FBM)1. Board foot = L x T x W 12Divide by 12 if length is in feetDivide by 144 if length is in inches

2. Materials used in farm constructionThree major kinds of materials used in farm construction:Wood, steel & masonry

3. Classifications of lumber Two Classifications of lumber:Softwoods - pine, cedar, fir, redwood, cypressHardwoods - oak, ash, birch, cherry, sycamore, walnut, hickory, mapleAlmost impossible to nail hardwoods & in knots in softwoods

4. Farm BuildingsMade of softwoods

5. Grades of softwoodsTwo grades of softwoodCommonSelect - knot free for finish work

6. Uses of common lumberCommon No. 1 & 2 used for rafters & joistCommon No. 3 used for studs & platesCommon No. 4 & 5 where strength is not a factor

7. Dressed lumberA dressed 1 x 4 is actually 25/32 x 3-5/8

8. Lumber for specific jobsconcrete forms-pine,fir No. 1 & 2framing building-pine & fir No. 1,2,3roof sheeting-pine & fir No. 2 & 3siding-redwood & cedarfloors-pine & oak select lumber others above are common grades

Fencing materialsWhen selecting fencing consider:1. type of livestock2. permanency

Types of paint1. exterior 2. interior3. floor 4. roof5. enamel 6. barn7. masonry 8. metal or implement paint

Rafter length formulaa squared + b squared = c squaredtake square root of c squaredsubtract half the thickness of ridge boardadd length of overhangabc

Draw a bill of materials for a projectAssignment #2

Drawings and sketchesCreating woodworking project plans using simple drawing techniques.

4. Purpose of drawings and sketchesOvercome mechanical, construction and repair problems

5. Plans (drawings)Are your most important guide

8. Advantage of having a bill of materialsSaves time and waste

7. Bill of materialsAmount, size and kind of each item needed to construct something

Application- make a projection drawing of a woodworking project such as an Ag. in the Classroom Storage Chest (include a top, front , right end views and a bill of materials).

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