BC CARPENTER APPRENTICESHIP PROGRAM LEVEL (Harmonized)

Transcription

1 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL (Harmonized) Line C: Tools and Equipment Competency C-3: Use Stationary Power Tools

2 2017 Industry Training Authority of British Columbia This publication may not be reproduced in any form without written permission by the Industry Training Authority. Version 2, New, November 2017 ISBN Permissions C3 LT1 Figure 1, Self Test 1 Figure 1, C2 LT2 Figure 2, Self Test 2 Figure 2, and C3 LT3 Figure 2 courtesy of Ridge Tool Company (RIDGID). C3 LT3 Figures 3 5 courtesy of Grizzly Industrial Inc. Acknowledgments The Industry Training Authority of British Columbia would like to acknowledge the Carpentry Articulation Committee and Open School BC, a division of the BC Ministry of Education, as well as the following individuals and organizations for their contributions in updating the BC Carpenter Apprenticeship Learning Guides: Carpentry Articulation Curriculum Committee members Dennis Carlson, Tom Haag, Erik Hardin, Alf Leimert, Geoff Murray, Don Naidesh, Stephen Pelley, Al van Akker Writers: Gary Backlund, Gary Henderson Reviewers: Trevor Feddersen, Roy Mironuck, Geoff Murray, Don Naidesh, Stephen Pelley Open School BC Christina Teskey, project management Dennis Evans, photography, illustration Sharon Barker, print layout Beverly Hooks, print layout Shannon Sangster, copyright management, art coordination Max Licht, illustration Greg Aleknevicus, editing Keith Learmonth, editing Ordering Crown Publications, Queen s Printer PO Box 9452 Stn Prov Govt Victoria, BC V8W 9V7 Phone: Fax: crownpub@gov.bc.ca Web:

3 Contents Program Outline Learning Task 1: Use a Jointer Self-Test Learning Task 2: Use a Thickness Planer Self-Test Learning Task 3: Use Sanding Machines Self-Test Answer Key

4 Disclaimer The materials in these Learning Guides are for use by students and instructional staff, and have been compiled from sources believed to be reliable and to represent best current opinions on these subjects. These manuals are intended to serve as a starting point for good practices and may not specify all minimum legal standards. No warranty, guarantee or representation is made by the Carpentry Articulation Committee, the British Columbia Industry Training Authority or the Queen s Printer of British Columbia as to the accuracy or sufficiency of the information contained in these publications. These manuals are intended to provide basic guidelines for carpentry practices. Do not assume, therefore, that all necessary warnings and safety precautionary measures are contained in this Competency and that other or additional measures may not be required. These materials contain information that has been derived from information originally made available by the Province of British Columbia at: and this information is being used in accordance with the Queen s Printer License British Columbia available at: License_1.0.html. They have not, however, been produced in affiliation with, or with the endorsement of, the Province of British Columbia, and THESE MATERIALS ARE NOT AN OFFICIAL VERSION. Safety Advisory Please note that it is always the responsibility of any person using these materials to inform him or herself about the Occupational Health and Safety Regulation pertaining to his or her work. The references to WorkSafeBC safety regulations contained within these materials may not reflect the most recent Occupational Health and Safety Regulation (the current standards and regulation in BC can be obtained on the following website: Symbol Legend Electric shock: This icon is a reminder for potential electric shock. Explosive: This icon is a reminder for a possibly explosive situation. Flammable: This icon is a reminder for a potentially flammable situation. Important: This icon highlights important information. Poisonous: This icon is a reminder for a potentially toxic/poisonous situation. Resources: The resource icon highlights any required or optional resources. Safety gear: The safety gear icon is an important reminder to use protective equipment. Self-Test: This icon reminds you to complete a self-test. We want your feedback! Please go to the BC Trades Modules website ( to enter comments about specific sections that require correction or modification. All submissions will be reviewed and considered for inclusion in the next revision.

5 Program Outline Line B Documentation and Organizational Skills B-1 Use Construction Drawings and Specifications B-2 Interpret Building Codes and Bylaws Line C Tools and Equipment C-2 Use Portable Power Tools C-3 Use Stationary Power Tools C-4 Use Oxy-Fuel Equipment Line D Survey Instruments and Equipment D-2 Use Site-Layout Equipment Line F Site Layout F-1 Lay Out Building Locations Line G Concrete Formwork G-4 Build Slab-On-Grade Forms and Suspended Slab Forms G-7 Place and Finish Concrete Line H Wood Frame Construction H-2 Select Framing Materials H-4 Build Wall Systems H-5 Build Stair Systems H-6 Build Roof Systems Line I Finishing Materials I-1 Describe Roofing Materials I-2 Install Doors and Hardware I-3 Install Windows and Hardware I-4 Install Exterior Finishes Line J Building Science J-1 Control the Forces Acting on a Building J-2 Control Heat and Sound Transmission J-3 Control Air and Moisture Movement in Buildings BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 1

6 Competency C-3: Use Stationary Power Tools Jointing boards is the first step in surfacing rough lumber. The jointer is known as a dangerous woodworking machine. The cutters rotate toward the operator and can seriously injure the operator. Once you see a thickness planer in action and then imagine having to duplicate the task with a hand plane, you will appreciate the work a thickness planer does. It is one of the most efficient machines in a carpentry shop. Using it will save time and increase accuracy in many woodworking operations. Whether woodwork is to receive a transparent finish or a painted finish, great care must be taken to treat the surface first. The use of a sanding machine makes this task fairly easy. To safely operate any of these stationary power tools effectively, you must know how they operate and how to maintain them. Learning Objectives When you have completed the Learning Tasks in this Competency, you will be able to: describe the use and maintenance of shop equipment use and maintain shop equipment Competencies Written: Use Stationary Power Tools You will be tested on your ability to identify the parts, functions of each part, the correct techniques, as well as the safety precautions and maintenance procedures for each stationary shop tool covered in this Competency. Practical: You will be required to use these tools correctly while performing various finishing projects. You will be required to demonstrate safe work practices and the maintenance procedures for each tool. 2 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

7 Competency C-3: Use Stationary Power Tools Learning Task 1 LEARNING TASK 1 Use a Jointer Parts of a Jointer Jointers can be used for a variety of tasks. They can be used to remove warp and twist from a board and dress it flat and true. They can also be used to rabbet, taper, bevel and chamfer stock. For all these tasks, the jointer cuts smooth, straight, square edges, ensuring strong glue joints. Although jointers come in various types and sizes, all have similar parts, including a heavy base or frame, a front infeed table, an adjustable fence, a cutterhead protected by guards, a rear outfeed table, a rabbeting ledge and several adjusting wheels and scales (Figure 1). Outfeed table Rabbeting ledge Cutterhead guard Fence control handle Infeed table Depth adjustment scale Outfeed adjustment knob Depth of cut hand wheel ON/OFF switch Figure 1 Main parts of a jointer lnfeed and Outfeed Tables The surface of the front infeed table is straight and flat and made of machined cast iron. The height of the adjustable infeed table governs the depth of cut the lower the table, the deeper the cutterhead planes the stock. The second purpose of the infeed table is to support the work as it s fed into the cutterhead. The outfeed table at the back of the jointer governs the straightness of material passed through the jointer. It also supports the work after it has been planed smooth and flat by the cutterhead. Its construction is similar to that of the infeed table, except that its height is aligned with the knives in the cutterhead. The outfeed table is used as a guide for installing and setting the knives in the cutterhead. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 3

8 Competency C-3: Use Stationary Power Tools Learning Task 1 Fence The fence, which is attached to either the infeed table or the jointer frame, looks and functions like the fence on a table saw. It guides the work at a constant angle to the cutterhead as the work passes over the cutterhead. It s made of cast iron and its face has been ground flat and straight. It can be moved crosswise and tilted up to 45 from the vertical position. Cutterhead The cutting part of the jointer is a solid metal cylinder that carries several (usually three) sharp steel knives (Figure 2). Each knife is carefully balanced and held securely in a matching recess in the cylinder. This ensures rotation at a high speed, with no vibration. Figure 2 Standard cutterhead Jointer knives must be kept sharp in order to leave the surface of the workpiece smooth and clean. Sharpening must be done with a stone, as the high-speed steel in a jointer knife is too hard to sharpen with a file. If the jointer is equipped with solid-carbide knives, use a diamondembedded stone for sharpening. The length of the knives in the cutterhead sets the size of the jointer. The most common sizes are 150 mm and 200 mm, but both smaller and larger sized machines are available. The length of the knives also limits the width of the material that can be jointed on the flat. A new type of cutterhead with segmented knives is becoming popular. The knives are square with four cutting edges. When the knives become dull, they are loosened and turned 90 degrees in order to use a new cutting edge. After all four edges are used, the knives are replaced (Figure 3). 4 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

9 Competency C-3: Use Stationary Power Tools Learning Task 1 Figure 3 Helical cutter head with segmented knives Guards Guards cover parts of jointer knives that are not in use. The front guard is held by spring pressure against the workpiece. Some jointers have a second guard on the opposite side of the fence that covers the unused portion of the cutterhead. Frame The frame, also referred to as the base, is made of heavy cast iron. Floor models will also feature a heavy metal column. The frame supports the cutterhead bearings, the infeed table and the outfeed table, and maintains their alignment. Adjusting Hand Wheels and Locks The jointer has two hand wheels or a lever system for making adjustments. Both have locks. The hand wheel on the infeed table sets the depth of the cut. It s often located directly under the table, or on the operator s side of the machine. Usually there is a depth scale close to it. The hand wheel on the outfeed table sets the table to the height of the knives. Normally, once this height is set, the wheel is not moved again until the knives are replaced or serviced. Always lock the tables in place after adjusting. Do not adjust the outfeed table without the instructor s permission. Rabbeting Ledge The rabbeting ledge is a side extension of the infeed table. It gives extra support to material that is being rabbeted. Sometimes it s an integral part of the infeed table, and sometimes it s sold as an accessory. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 5

10 Competency C-3: Use Stationary Power Tools Learning Task 1 Power Switch The power switch turns the jointer on and off. Fence Control Handle The handle that controls the fence releases and locks the fence at the desired angle to the table and at the desired position along the width of the table. Tilt Scale and Pointer The tilt scale is used to set the tilt of the fence. There will likely be positive stops at 90 and 45. To set the fence to any other angle, you must read the tilt scale. The pointer is adjustable it should be set at 0 when the fence is square to the table. Operations Performed with a Jointer The jointer gets its name from its ability to flatten the face and straighten the edge of a board, making the board ready for ripping, planing or making a joint. Facing and Edging The jointer is used for much more than making edge joins. The jointer is a stationary power tool used in finish woodwork for planing surfaces flat. Hardwood lumber usually arrives at the shop in a very rough form. The jointer is the primary tool used in preparing the rough stock for cabinet and furniture construction. Outfeed Table Height The height of the outfeed table is critical to the operation of the jointer. The outfeed table should be set to the same height as the top of the knives. When checking or setting the outfeed table, the cutterhead must be in the top-dead-centre position (Figure 4). Jointers often come with set-up tools that help position the knives at precisely the right height. If the outfeed table is set correctly, the leading edge of the cutter should just barely touch the straightedge. It s best to have the knife actually touch the straightedge rather than merely coming close to it. Straightedge Outfeed table Infeed table Figure 4 Cutterhead at top-dead-centre position 6 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

11 Competency C-3: Use Stationary Power Tools Learning Task 1 After newly sharpened knives have been used for a while, the outfeed table may have to be lowered but only to a height where the knife just touches the straightedge. Snipe A snipe is a distinct change in thickness that occurs at the end of a board. The snipe is caused by having the outfeed table set too low. Raise the outfeed table to match the height of the knives to prevent snipes. Infeed Table Height Always check the infeed table height before jointing. The height of the infeed table sets the depth of cut of the jointer. The depth of cut should be shallow for wide boards. Always check the depth of cut before using a jointer. It s a good practice to return the depth of cut to 1 mm when you are finished with the jointer. If the jointer is left set for a deep cut, the next operator could be seriously injured, as kickbacks can occur when the depth of cut is deep. Volume-of-cut The depth of cut may be set deeper for narrow boards, but it must be set shallow for wider boards. The volume-of-cut is a combination of the width of the board, the depth of cut and the feed rate. It s the volume of wood cut away that will affect the cutterhead speed. If the volume-of-cut is too great, it can cause the cutterhead speed to slow, increasing the chance of a kickback. Slope of the Grain Check the angle of the grain before making a pass over the jointer. The jointer knives should be cutting with the grain as shown in Figure 5. Figure 5 Jointing with the grain Jointing against the grain is dangerous and produces a chipped surface. When jointing boards with confused grain, you ll end up jointing against the grain. Listen carefully to the sound of the cutting action. If you hear a decided change in pitch, you may be cutting against the grain. Slowing the feed rate will reduce the chipping but will not eliminate it. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 7

12 Competency C-3: Use Stationary Power Tools Learning Task 1 If a knife in the cutterhead is chipped, it will leave a bump on the surface of every board that passes over it. Before jointing lumber, make sure the boards are free of dirt, sand, small stones and nails. Jointing Crooked, Cupped, Bowed or Twisted Boards Always place the concave surface of a crooked, cupped or bowed board down this will stabilize the board, making jointing easier. Often many passes are needed to straighten a badly crooked board. It s important to cross cut (shorten) the piece closer to its final length to reduce waste. For twisted boards, you ll have to balance the twist on the infeed table and try to keep the board in the same plane (keep the board from rocking) as it crosses over the cutterhead. On the second pass of a twisted board, the board should balance better. It should be stable on the third pass. Surfacing Rough Stock (Breaking Out) The face (wide surface) of a rough board is always jointed first. Reduce the volume-of-cut by setting the depth of cut to a shallow depth (less than " or approximately 1 mm) and joint the face of the board flat. Maintain pressure on the outfeed table to ensure a straight cut. Many passes over the cutterhead are often required to flatten a rough board. The board s face cannot be wider than the cutting head for this type of jointing. Put the now flattened face against the fence and joint the edge straight. If the fence is square to the table then the edge of the board will be square to the face. The board is then planed to thickness using a thickness planer and ripped to the finished width plus " on a table saw. The extra " is planed off using the jointer set to exactly ", leaving a board that is planed smooth on both sides and both edges. Tool marks: If the finished surface of the board has tool marks across its width, reduce the rate of feed for the planer and feed the board more slowly over the jointer. Thin stock: Jointing thin stock is dangerous! Take extra care and always use a push block. DO NOT attempt to joint stock thinner than 12 mm ( ") thick. Rabbeting The jointer can be used to make rabbet cuts in door and window jambs. Making rabbet cuts on a jointer requires the guard to be removed. Operating the jointer without the guard is very dangerous. Replace the guard immediately after finishing the rabbet cut. 8 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

13 Competency C-3: Use Stationary Power Tools Learning Task 1 To make a rabbet with the jointer (Figure 6): 1. Remove the guard over the cutterhead. 2. Move the fence until the exposed part of the knives is equal to the width of the rabbet and lock the fence in this position. 3. For the final pass, or the first pass if making the rabbet in one pass, set the depth of cut equal to the depth of the rabbet. 4. Make a trial cut into a piece of scrap wood and adjust as required. With a jointer, you can cut a rabbet in a single pass or in several passes. If you cut the rabbet in one pass, you must slow the rate of the feed to reduce the danger of kickback. If more than one pass is required, a cleaner rabbet cut is obtained if you cut the edge of the rabbet on the table saw before removing the main portion of the rabbet with the jointer. Figure 6 Cutting a rabbet with a jointer Cutting a Bevel An edge bevel stretches from one end of the stock to the other. To cut one on a jointer, perform the following steps: 1. Tilt the fence to the desired angle. 2. Lower the infeed table to the desired height. 3. Proceed with the cut (repeat until cut is complete). Care is required at greater angles, as the piece will tend to slip down the fence. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 9

14 Competency C-3: Use Stationary Power Tools Learning Task 1 Cutting a Chamfer A chamfer is a bevel that runs less than the full thickness of the workpiece. To cut one on a jointer, perform the following steps: 1. Tilt the fence to the desired angle (usually 45 ). 2. Lower the infeed table until you obtain the desired width of cut. 3. Proceed with the cut. Cutting a Taper To make a taper along the length of a piece of stock, you must start the cut with the front end of the stock just resting on the outfeed table, then joint as usual. With this positioning, the cut (that is, the amount of wood removed) will begin at nearly zero and finish at the full depth of cut you set for the jointer. Be aware that when you lay the front end of the stock so that it just reaches the outfeed table, there is a risk of kickback. Do not let the cutterhead pull the stock clear of the outfeed table. If the stock drops off the outfeed table into the cutterhead, the cutterhead will make a full depth cut in one bite, and this will cause kickback. If the taper is to slope more than 6 mm, make it in two or more passes. Clamp a stop block to the fence (Figure 7). Then set the end of the stock tight to the block. Gently lower the stock into the cutter and proceed to make the second or third cuts. Figure 7 Use a stop block to cut tapers Only shallow tapers can be made in one pass. One complete shallow pass may be needed with the stop removed, when the taper cut is complete. 10 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

15 Competency C-3: Use Stationary Power Tools Learning Task 1 Location of the Fence The fence should not be left in one position for a long time. By periodically moving its location to expose an unused portion of the knives, wear on the cutting edges of the knives will be even along their full length. If you leave the fence in one spot, one section of the knives will quickly dull. If you have to face wide stock, you ll need to sharpen the whole knife, even though some parts of the knives are still razor-sharp. Safety Rules for Operating a Jointer The safe procedures for operating a jointer are similar to those for operating any stationary rotating tool: Wear eye protection at all times. Keep your hands away from the cutter/blade. Use a push block if the work is small. Stand to one side of the direction of cut. Wear hearing protection at all times. An injury from a jointer is usually more serious than injuries from other stationary tools. The typical jointer injury is a severe cut to the right hand involving the removal of flesh and bone from the index finger, the ring finger and the small finger. Most jointer injuries are caused by a kickback. Kickbacks can be caused by: feeding the work too quickly cutting against the grain using dull cutting knives not holding the work securely During a kickback, the work is kicked out of the jointer by the cutter. The hand pushing the work into the jointer is pushed into the cutterhead before the guard has time to close and protect the operator. Keep Hands Clear It s very important to prevent either of your hands from coming in contact with the cutterhead: 1. Keep both hands behind the cutterhead when starting the cut. 2. Move your left hand onto the outfeed table once there is at least 300 mm of board to hold onto. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 11

16 Competency C-3: Use Stationary Power Tools Learning Task 1 3. Finish the cut with both hands on the outfeed table, or with the pushing hand using a push block. By following the above steps, neither hand is ever over the cutterhead if a kickback occurs, both hands will be clear. Push Block A push block (Figure 8) can be used to keep your hands away from the cutterhead. Do not use fasteners to attach the stop block to a push block. When jointing thin boards, it s possible for the stop to contact the cutterhead and fasteners will damage the knives. If the stop block gets worn or cut down, plane it off and cut a new dado and fit a new stop block. Figure 8 Various types of push blocks and push stick Jointer Safety Rule Checklist Wear eye protection, secure lose clothing and tie back long hair. Wear hearing protection. Lock the fence into position before you start work on the jointer. Make sure that the guards are in place and operating freely. Check the depth of cut. Never place your hand over an operating cutterhead. Do not drag your thumb at the back end of the stock. Keep your fingers as high as possible on the side of the stock. Do not joint stock that contains loose knots, splits, structural defects or embedded metal or stone. Do not joint stock shorter than 300 mm (12"). 12 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

17 Competency C-3: Use Stationary Power Tools Learning Task 1 Do not edge-joint stock that is less than 20 mm ( ") wide use a push block for narrow stock. Do not face-joint stock that is less than 12 mm ( ") thick use a push block for all thin material. Maintain secure footing by keeping the work area free of debris. Turn the jointer off and wait until the cutterhead comes to a full stop before cleaning. Use a brush to clear any shavings from the table. Remove the front guard only when making a rabbet cut (this operation is extremely dangerous and extra care is required). Reset the depth of cut to 1 mm after using the jointer. Allow the cutterhead to reach full speed before starting a cut. Feed the work at a rate slow enough that it does not reduce the speed of the cutterhead. Do not stand directly in line with the jointer. Always stand to the side of the machine. Do not leave the jointer until the cutterhead comes to a full stop. Basic Maintenance of a Jointer Maintenance and safety go hand in hand. The following are procedures for basic maintenance of the jointer. Unplug or lock out the jointer before conducting maintenance, adjustments or cleaning. Guards Clean around the guards and ensure they operate properly. Guards are spring-activated and occasionally need tensioning. Tables Check the tables to make sure they re aligned with each other. To do this, take a long straightedge and see if it touches both tables along their full length when the infeed table is set at zero depth of cut. If this requirement is not met, straight jointing is impossible. Clean the surfaces of both tables, removing rust spots, pitch marks and other accumulations. Coat the surfaces with paste wax or silicone and polish them. Keep sliding parts and table control screws lubricated with machine oil. Test the slides for tightness by lifting the end of each table. You should feel no movement between the tables and the base of the jointer. If you do, the slides need tightening. Remove all burrs and nicks with a smooth file. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 13

18 Competency C-3: Use Stationary Power Tools Learning Task 1 Fence Check the operation of each fence by moving it to different positions. Clean the surface of the fence, removing any rust spots, pitch marks and other accumulations. Apply paste wax or silicone, and polish. Use a combination square or a try square to check the fence for square and adjust set screws if needed. Pointers and Scales Set the infeed table to zero depth of cut. Set the indicator on the infeed scale to zero. With the fence at exactly 90 to the tables, set the pointer on the tilt scale to zero. Cutterhead Check the condition of the cutting edge of the knives. Sharpen or replace dull or nicked knives. Rotate the cutterhead slowly and feel the action of the bearings. They should roll smoothly. If you feel hesitation, the bearings may need replacing. Clean accumulated pitch from the cutterhead and check to make sure that the bolts holding the knives in place are tight. Castings Inspect all cast iron parts of the jointer. Replace any that are cracked. Wiring Have a qualified electrician replace any damaged electrical wiring. Belts Check the condition of the belts tighten any that are loose and replace any that are worn. Outfeed Table Adjustment The top of the outfeed table should be exactly level with the highest cutting arc of the knives. Regularly check this alignment by laying a straightedge on the table and extending it over the cutterhead. When it s laid flat against the table, the straightedge should just touch the blades of the cutterhead when the cutter is turned by hand. To align the outfeed table, first loosen the rear table lock screw if the jointer has one (it s usually on the right side). Then use the hand wheel to raise or lower the table until it s level with the highest point of the cutting arc of the knives. When the table is set to the correct height, lock the hand wheel to prevent the table from moving. 14 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

19 Competency C-3: Use Stationary Power Tools Learning Task 1 Knife Adjustment When changing the knives, set them so that, when they are at the top of the arc, all their cutting edges are at the same height. The procedure for setting the knives varies with the model of jointer. Some cutterheads have a lifter spring beneath each blade. When you loosen the knife lock bar, the spring forces the blade out of the head. Other cutterheads have raising screws, which are located at each end of the blade slot. These screws have an extended shoulder that fits under the blade and acts like a cam. When the screw is turned, the shoulder lifts the knives. To raise the blade on other cutterheads, you must insert a small punch under the end of the blade. To lower the blade, use a piece of hardwood to push it down. Check the machine you re working on to see how the knives are adjusted. Regardless of the procedure, the knives are always adjusted to the level of the outfeed table. Dial Indicator The best way to accurately set knives in the cutterhead is through the use of a dial indicator (Figure 9), as it can read changes of of an inch. This device has a magnetic base and an adjustable arm. To use it, mount the magnetic base on the outfeed table and move the arm until the dial indicator rests on the table. Record the reading. Move the base over the table until the indicator is over the knives. Adjust the knives so that when they are at the top of their arc, the dial indicator reads as it did when it was resting on the outfeed table. Figure 9 Dial indicator with magnetic base Now complete Self-Test 1 and check your answers. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 15

20 Self-Test 1 1. Name the parts of the jointer in Figure 1. a. b. c. e. f. g. d. h. i. Figure 1 a. f. b. g. c. h. d. i. e. 2. What is the name of the part that supports the work after it has been planed? 3. The length of the determines the size of the jointer. 4. The outfeed table of the jointer must be set to exactly match the height of the. 16 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

21 Competency C-3: Use Stationary Power Tools Learning Task 1 5. What is the cause of the problem that is indicated when a snipe or gouge appears at the end of a cut? 6. Lumber that is bowed across its width should be jointed with the cupped side. 7. With which part of the jointer must the stock make full contact if you want a straight cut? 8. You should reduce the feed rate when you plane a face. 9. What adjustment must you make to the jointer fence in order to cut a chamfer? 10. Where should you stand in relation to the machine when jointing a board? 11. Kickbacks are more likely to occur when the jointer is set for a. 12. To ensure that the fence of the jointer is perpendicular to the table surface, periodic checks should be made with a. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 17

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23 Competency C-3: Use Stationary Power Tools Learning Task 2 LEARNING TASK 2 Use a Thickness Planer Parts of a Thickness Planer A thickness planer is capable of doing only one task it dresses lumber to a uniform thickness. Most of the planer s parts are hidden from view. Figure 1 shows the major parts that are not visible during a planing operation. Outfeed roller Pressure bar Cutterhead Rotation Chip breaker Knife Infeed roller Feed Table Top surface cut parallel to bottom surface Lower outfeed roller Lower infeed roller Figure 1 Cross-sectional view of a thickness planer Knives and Cutterhead The rotation of the knives in the cutterhead is between 4000 and rpm. This speed is necessary for planing a wood surface to a smooth, uniform thickness. It s equally important that the knives and the cutterhead be exactly parallel to the table, otherwise there will not be uniform thickness. Knives are usually made of high-speed steel, although carbide blades are available. Smaller planers have knives supplied in single lengths to match the width of the cutterhead. However, some larger planers have segmented knives. Segmented knives are made up in short sections, which are individually mounted in the cutterhead. They re less prone to warping and dull edges. If a cutter becomes severely nicked, only the short section where the damage occurs needs to be replaced. Mounting segmented knives in the cutterhead, however, takes a great deal more time than mounting straight knives. Upper Rollers There are two upper rollers: the upper infeed roller and the upper outfeed roller. Both are under power and spring-loaded. The amount of tension on the springs can be adjusted to suit the hardness of the material being planed. The upper infeed roller has a serrated surface that grips BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 19

24 Competency C-3: Use Stationary Power Tools Learning Task 2 the lumber and forces it forward (right-to-left in Figure 1). The upper outfeed roller is smooth and often rubber coated. It pulls the lumber through the planer after it clears the infeed roller. The upper infeed roller on some thickness planers is made up of short sections. Each section contains an internal spring mechanism that allows it to operate at a height different from that of the adjacent section. Segmented in-feed rollers allow you to feed pieces of stock that are a different thickness through the planer at the same time. If this is done using a thickness planer with a solid infeed roller, the thinner pieces will be loose and may not feed correctly or may kick back. Lower Rollers The two lower rollers, the lower infeed roller and the lower outfeed roller, may be idlers, or they may be under power. Their purpose is to prevent lumber from dragging too heavily on the table. Pressure Bar The spring-loaded pressure bar presses the lumber to the surface of the table to prevent chattering. The tension of the springs can be adjusted to suit the material being planed. For example, wide boards require more pressure than narrow boards. Chip Breaker The chip breaker prevents the knives from tearing long slivers from the wood. It also presses the wood to the table to prevent chatter. External Parts The external parts of a thickness planer are shown in Figure 2. Examine the illustration carefully to locate each part. Depth adjustment knob ON/OFF switch Thickness adjustment scale Depth of cut gauge Variable speed adjustment Infeed/outfeed table Figure 2 External parts of a thickness planer 20 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

25 Competency C-3: Use Stationary Power Tools Learning Task 2 On-Off Switch The on-off switch controls electrical power to the motor, which in turn powers the cutterhead and the two upper rollers. Table The table supports the lumber as it passes through the thickness planer. Elevating Wheel and Lock The elevating hand wheel is used to adjust the thickness setting of the planer. On some models, it raises and lowers the table and the two lower rollers as a unit. Other models have the wheel at the top of the planer, and it raises and lowers the upper assembly. When there is a lock for the hand wheel, it should be engaged to prevent the hand wheel from moving accidentally when many pieces are to be planed to the same thickness. Most large planers have a motorized elevating system to raise and lower the table and adjust the depth of cut. Thickness Scale and Pointer A scale and pointer indicate the thickness setting. The scale shows how thick the material will be when it leaves the planer. Bed Roller Adjustment The bed roller adjustment control raises and lowers the two lower rollers within the table. To feed lumber with a rough surface through the machine, the two lower rollers may have to be raised higher in the table. Rate of Feed The rate of feed (the speed at which lumber travels through the planer) can be adjusted on some models by turning or pulling the variable speed feed-roller control. Most planers have a rate of feed of feet per minute. Chip Guard The chip guard directs the flow of chips and shavings away from the operator and toward a dust-collecting attachment. Anti-kickback Fingers Anti-kickback fingers are an added safety feature on many planers. The fingers will prevent a board from being pulled backwards from the feed direction. They re suspended from a rod that hangs in front of the upper feed roller. The fingers should be inspected regularly to make sure they swing freely. If it s necessary to pull a board out of the planer, you must turn the elevating wheel several rotations in order to open the planer. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 21

26 Competency C-3: Use Stationary Power Tools Learning Task 2 Operating a Thickness Planer When a thickness planer is equipped with sharp knives and all the parts that make contact with the wood are properly adjusted, the operation of this machine is simple. You ll set the planer for the desired thickness, feed the lumber in at one end, and retrieve it planed on the upper surface at the other. The machine does all the work. Observe the following rules when using a planer: Planing must be done with the grain, not against it. The grain of the wood must slope downward toward the front of the stock. Planing with the grain sloping the wrong way produces a chipped surface. If both sides of the stock need planing, you must turn the stock over and end-for-end after you plane one side in order to plane the second side in the correct direction. The amount of stock to be removed during each pass should not exceed 3 mm. On wide pieces, this should be reduced to about 1 mm. This is an example of adjusting for the volume-of-cut. You must watch for tapered stock. This condition is sometimes found in rough-sawn stock. If you encounter a tapered piece of lumber, set the cut to accommodate the thickest part of the wood, send the thick end through first, and make as many successive passes as needed to cut the stock down to a uniform thickness. The bottom surface of the lumber being planed should be free of cupping, twist and bowing. The thickness planer cannot produce a straight, flat surface unless the bottom of the stock is straight and flat. Bowed, warped and twisted stock should have one surface jointed flat before it passes through a thickness planer. Stock should be at least as wide as it is thick. The thickness planer should not be used to plane the edges of boards, as the boards tend to lean over as they pass through the planer, and this leaves the edges bevelled rather than square. Plane only dimensional natural wood. Do not try to plane plywood, laminates, particle board, plastics, etc. When planing a large number of pieces, examine each as you transport it to the front of the planer. Place it with the side to be planed facing up, and the piece turned so that the cut will be with the grain. If both faces are to be planed, turn each piece end-for-end as you return it to the front of the planer and again stack it with the face to be planed facing up. By following these steps, you ll maintain proper grain direction without having to re-examine each piece of wood. When planing rough stock, some boards may be thicker than others. Start with the thickest boards. Once a pass or two has been made, the next thickest boards can be added to the queue, and so on until all boards are a uniform thickness. 22 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

27 Competency C-3: Use Stationary Power Tools Learning Task 2 If some pieces were incorrectly planed against the grain on the first pass, do not turn those pieces end-for-end for subsequent passes through the planer. If you re unable to flatten one face of a cupped board by jointing it, the following procedure should be used to dress it in a thickness planer: 1. Place the cupped side down and remove only a small amount from the crowned side. (If this first cut is too substantial, the stock may split as the planer s rollers force it flat.) 2. Repeat this process until at least half the width of the board is flat. 3. Turn the board over and plane small amounts from the cupped side until the entire side is planed flat. 4. If the board is still too thick, turn it over and plane it to the desired thickness. Safety Rules for Operating a Thickness Planer Because of the simplicity of its operation, the thickness planer is one of the safer machines in a woodworking shop. A rough plank is inserted at one end, and a smooth board emerges from the other. However, remember that the thickness planer is also one of the few woodworking machines that is power-fed. That is, it self-feeds material at a constant rate. Since this can be hazardous to the operator, you must be careful about the kind of stock you feed into the machine, the method you use to feed it and the position you take when you remove it. Before Starting the Planer Examine the thickness of the stock before you plane it. Plane boards that are thinner than 10 mm by placing the thin board on top of a thicker board, and then feed both boards through the planer together. Examine the width of the lumber. Most thickness planers remove no more than 3 mm per pass. If a narrow piece of lumber is being planed, the machine will easily remove a maximum cut. However, if the plank is the full width of the bed, the amount removed in each pass (the volume-of-cut) should be reduced to prevent overheating the motor or stalling the cutter. Examine the length of the stock. The shortest stock that can be safely planed is 50 mm longer than the distance between the infeed and outfeed roller. Shorter stock will jam the machine. Before planing long stock, make sure there s enough room at the rear of the planer to accommodate that length. If the stock being planed is thicker at one end than the other, insert the thick end first to avoid jamming or stalling. Before inserting a plank into the planer, check the board for loose knots that could come free during the planing. These knots could harm you or the machine. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 23

28 Competency C-3: Use Stationary Power Tools Learning Task 2 Do not plane painted or varnished lumber, as the finish will quickly dull the machine s knives. Check the surfaces of a plank for nails, staples, dirt, sand, glue or other foreign matter that could damage the knives. Never plane lumber that does not have the ends cut square. Broken or mitred ends can catch on the pressure bar and jam. Make sure the dust-removal equipment is operating before starting a planer. Before starting the planer, lower the table and remove any shavings, loose knots and slivers of wood from the table and roller assembly. While Using the Planer As in any woodworking operation, the way a machine is handled reflects the operator s skill and knowledge. When a thickness planer is properly set up and the knives are sharp, it does a good job of smoothing the surfaces of lumber usually very little sanding is needed. In order to achieve superior results, consider the following: Stand to the side when you feed or tail the planer. Do not allow the stock to slide through your hands as the machine self-feeds. If a large sliver catches on your clothes or hands, serious injury can result. Use the full width of the planer. Alternate between the left, right and centre positions. This ensures that planer blades (knives) wear evenly. Never view the cutting action of a thickness planer, not even from the back of the machine. A loose knot or long sliver may eject from the machine and strike your eye. To keep internal tensions in the wood from bowing the board, plane equal amounts from each face. Be careful when planing short stock. The infeed rollers can cause short stock to quickly tilt up, then down, pinching your fingers between the table and stock. When planing multiple pieces to the same thickness, position the next board slightly offset but tight against the trailing end of the one currently being planed. This will help reduce snipe. When removing lumber from the outfeed side of the planer, do not stand between the stock and an immovable object such as a wall. If the planer stalls, turn off all power sources and wait for all motors to stop. Then lower the bed and remove the stock before restarting the machine. Do not attempt to plane short stock or stock thinner than 10 mm without the instructor s supervision. 24 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

29 Competency C-3: Use Stationary Power Tools Learning Task 2 Basic Maintenance of a Thickness Planer Like all woodworking equipment, the thickness planer performs satisfactorily only if it s properly maintained. The following are basic procedures that will keep a thickness planer in good running order: Refer to the owner s manual for maintenance procedures and instructions. Lock out the power supply before proceeding with any maintenance. Clean and polish the table. A clean, smooth tabletop will prevent lumber from hesitating or stopping during a planing operation. Use a petroleum-based solvent to clean the table. Remove rust marks with steel wool or silicon carbide sandpaper. Polish with paste wax. Use a petroleum-based solvent to clean all accumulations from the rollers. Pitch and wood dust tend to collect on their surface, and this accumulation leaves indentations on the smooth face of lumber. Make sure the table moves up and down freely. Clean and lubricate the mechanism that controls the table height. Again, check the table to make sure that it locks at any position. Do not use if the table does not stay locked where set. Ensure that the variable speed control operates smoothly. Do not use if it does not. Make sure that the chip breaker moves up and down freely to accommodate stock of different thickness. Some are spring-loaded, others are held tight to the wood by weights. Ensure the lower rollers move freely. Clean wood chips from the slot in the table that houses the lower rollers. Clean and lubricate the mechanism that raises and lowers the rollers. If, in spite of this, the rollers do not operate smoothly, notify your supervisor. Replace or have knives sharpened when dull or nicked. Dull knives will make planing even noisier than normal. The planer may bog down or leave burn marks on the boards. Nicked knives will leave raised lines on the boards. Consult the owner s manual to perform the following: Check the height and pressure setting of the upper feed rollers. These rollers should be set at exactly the same height as the lowest arc of the knives. Check and adjust the height setting of the lower rollers. If set too high, these can cause snipe. If set too low, the wood can stall or jam. Check the height setting for the chip breaker and pressure bar. Check the condition of the electrical wiring. If the pressure bar allows the planed lumber to chatter, this is an indication that the bar is set too high. If the lumber does not feed smoothly after it has cleared the infeed roller, the pressure bar may be set too low. In either case adjust the bar according to the owner s manual. Now complete Self-Test 2 and check your answers. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 25

30 Competency C-3: Use Stationary Power Tools Learning Task 2 Self-Test 2 1. What control on a thickness planer sets the thickness the lumber will be after it has been planed? 2. The pressure bar and the chip breaker prevent the lumber from. 3. In Figure 1, in which direction is the lumber travelling? b. c. Rotation e. d. a. f. Table h. Figure 1 g. 4. Name the parts illustrated in Figure 1. a. e. b. f. c. g. d. h. 26 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

31 Competency C-3: Use Stationary Power Tools Learning Task 2 5. Name the parts illustrated in Figure 2. c. a. d. b. e. f. Figure 2 a. d. b. e. c. f. 6. Explain the advantage of segmented infeed rollers in a thickness planer. 7. What is the purpose of the upper outfeed roller? BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 27

32 Competency C-3: Use Stationary Power Tools Learning Task 2 8. Explain the role of the lower rollers in a planing operation. 9. Which part of the thickness planer directs the flow of chips away from the operator? 10. In which direction should the grain slope when you plane lumber in a thickness planer? 11. In a single pass through a thickness planer, wide boards should have no more than mm of stock removed. 12. The thickness planer is known as a specialty machine because it does only one thing. a. true b. false 13. To obtain a straight, flat cut in a thickness planer, lumber must be and. 14. Explain how lumber must be turned in order to have both sides planed with the grain. 15. When you feed lumber into a thickness planer, where should you stand? 16. Before starting the thickness planer, clean away debris from the. 17. Before you plane a long plank, what should you check for? 28 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

33 Competency C-3: Use Stationary Power Tools Learning Task Most thickness planers remove no more than. 19. What should you do if a plank gets stuck or the cutter stalls during a planing operation? 20. What adjustments should you make when you plane wide planks in a thickness planer? 21. What happens to the thickness planer if you try to plane painted or varnished lumber? 22. What happens if the grain of the plank you run through a thickness planer is in the wrong direction? 23. In the correct sequence, name the parts of a planer the upper surface of a plank touches as it goes through the machine. 24. If you remove too much stock at one time with a thickness planer, you risk overheating the. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 29

34 Competency C-3: Use Stationary Power Tools Learning Task If the plank you want to plane is thicker at one end than at the other, what should you do? 26. You risk pinching your fingers if you plane stock that is. 27. Describe what you should do if the stock you wish to put through the thickness planer has ends cut at What should you use to remove dirt, pitch and gum from the surfaces of a thickness planer? 29. Why is it important to clean the rollers of a thickness planer? 30. If stock sticks or hesitates in a thickness planer, what could cause the problem? 31. What can cause lumber to chatter as it passes through a thickness planer? 32. If you find that lumber does not leave a planer properly, what might be the cause? 30 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

35 Competency C-3: Use Stationary Power Tools Learning Task 3 LEARNING TASK 3 Use Sanding Machines Types of Sanding Machines There are many types of stationary sanding machines, including the belt sander, wide belt sander, drum sander, stroke sander, disk sander and vertical oscillating spindle sander. Belt Sander Sometimes called a finishing sander, a belt sander is used for the final sanding of straight stock small enough for one person to handle. It s a versatile machine. As shown in Figure 1, it can be set up as a vertical belt sander, with a table to hold work square to the surface of the belt. It can form bevels and chamfers if you tilt it to an upright position and use a table, complete with mitre gauge, to guide the work past the belt. Figure 1 Belt in upright position On some models, you can remove the belt guard to expose the sanding belt as it passes over the end roller. With this set-up, you can sand various shapes, including internal curves, provided that its radius is at least as large as that of the roller. When it s used for sanding shapes, the belt sander is tilted to position the end roller at a convenient working height. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 31

36 Competency C-3: Use Stationary Power Tools Learning Task 3 Tracking guide knob Stop block Belt tension adjustment Rollers Adjustable table Sanding spindles Spindle table inserts ON/OFF switch Figure 2 Parts of a belt sander with stop at end of table Parts of a Belt Sander Motor The motor turns one of the rollers at the end of the belt. Power is transferred to the roller with a V-belt. Motor Switch The motor switch (Figure 2) turns the power on and off. Rollers At either end of the sanding belt is a roller (also called a drum) on which the sanding belt rides. One roller provides power to the belt, the other keeps the belt tracking properly. Both should be slightly crowned at the centre to keep the belt tracking correctly. Abrasive Belt The abrasive belt contains the abrasive that removes wood during a sanding operation. The belt is stretched tightly between the two end rollers and rides across a flat surface called the platen. Platen The platen is just behind the belt and is not shown in Figure 2. It s a smooth metal plate that holds the sanding belt against the work and thus ensures a flat sanded surface. If the sanding belt were simply stretched between two rollers, it would deflect when the workpiece presses against it, resulting in a convex curve. 32 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

37 Competency C-3: Use Stationary Power Tools Learning Task 3 Tracking Adjustment The idler roller (i.e., the roller not under power) has a tracking adjustment that tilts the roller slightly one way or the other. This tilting action allows the belt to ride in the middle of the rollers and thus track correctly. Adjustment is usually made with the belt running. Check the owner s manual for the correct method of adjusting tracking. Table A table is often supplied with a sanding machine. It may be adjustable so that it can be tilted 20 toward the belt and 40 away from it. It s used to support work when an accurate angle must be maintained during sanding. Fence and Stop Some models have a fence. The fence is aligned with the length of the belt and sits perpendicular to the belt s surface. The fence guides the stock during edge-sanding. The stop is positioned across the belt, near the end of the platen. It prevents small pieces from moving off the platen during sanding. The stop is also referred to as a backstop. Belt Tensioning Mechanism Some belt sanders have a spring-loaded roller that is used to apply tension to the belt. A lever retracts the roller to allow a belt change. When tension is desired, the lever is released. Other sanders have a belt tension knob, which applies tension to the belt as it s tightened. Tilt Mechanism, Scale and Pointer The table tilts on a trunnion under the table and is equipped with a tilt scale and pointer for reading the angle at which the table is tilted. Tilt Lock The tilt lock is used to lock the table at a specified angle. The tilt lock must be released before tilting the table, and locked after the desired angle is set. Height Adjustment The height adjustment raises and lowers the table in order to take advantage of the entire belt surface. Using the Belt Sander A belt sander is used in many different ways, depending on the size and shape of the stock. Sanding Long, Straight Stock Sanding straight stock is done with the belt sander positioned horizontally. The stock should be no wider than the width of the belt. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 33

38 Competency C-3: Use Stationary Power Tools Learning Task 3 With the sander running at full speed, gently place the front end of the stock on the belt at about the midpoint of the platen, and with light downward pressure and steady progression, move the stock forward against the direction of the belt until the end of the stock reaches the midpoint of the platen. Then lift the stock from the belt. This entire process should be done in one continuous motion. Do not stop or hesitate, as this would cause more material removal in one place than in another. Sanding Short, Straight Stock Short pieces should be sanded with the belt sander s backstop in place. The backstop is always positioned so that the belt travels toward the stop. Gently lower the stock onto the belt and let the motion of the belt move it against the stop. Apply gentle downward pressure and, at the same time, move the stock back and forth over the full width of the belt. Avoid applying more pressure on one side of the work than on the other, as this causes uneven sanding. Lift the stock from the belt when sanding is complete. Edge-sanding Edge-sanding is performed with the aid of a fence. Position the fence along the length of the belt and at 90 to its surface. Place the face of the stock against the fence. Then, applying very light pressure, move the stock along the fence until all the edge has been sanded. Light pressure is required because only a small area touches the belt. When edge-sanding multiple pieces, occasionally relocate the fence along the width of the belt. This prevents uneven wear and overheating of the belt. Sanding Curved Shapes Convex shapes are sanded by rotating the stock while holding it to the surface of the belt. If the curved edge must be square to the face of the work, use the fence or table as a guide. Concave pieces must be sanded against the idler roller. The diameter of the roller dictates how small a concave radius you can sand. Keep the work moving back and forth along the length of the roller. Belt Sander Maintenance and Safety 1. Check the platen. Most platens are composed of a thin sheet of metal supported on a rubber or cork cushion. To check the platen: a. Release the tension. b. Remove the belt. c. Inspect the platen for signs of wear or cracks. d. Carefully lift the metal sheet and check the condition of the cushion. 34 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

39 Competency C-3: Use Stationary Power Tools Learning Task 3 e. Remove any accumulated sanding dust, as this will cause pressure points on the platen that will result in uneven sanding. If left too long, dust accumulation will cause spots to wear through the platen. f. Replace the belt if it s worn. g. Apply tension, start the motor and adjust the tracking. 2. Check the condition of the rollers. Rollers tend to accumulate sanding dust. If left unchecked, the dust will build up until belt tracking is affected. Clean both the drive and the idler roller. 3. Check the condition of the fence. It should be free of burrs and should operate freely. Remove burrs with a smooth file, and clean and lubricate all moving parts. If you have trouble getting the belt to track properly, and if the rollers are clean, you can improve tracking by winding a few layers of masking tape around the centre of the rollers. In effect, this will increase the crown of the rollers, and the belt will centre itself on this highest point. Wide Belt Sander Wide belt sanders (Figure 3) can produce a better surface than can be done by hand. The range in sanding belt width varies from 15" to more than 36". Mostly found in furniture, cabinet and door manufacturing, these machines are great time savers for sanding large, flat surfaces such as a door face. They work by feeding the material in using a conveyor and sanding using a wide belt that runs over two or more rollers. Only a small portion of the belt is in contact with the material as it passes through. Figure 3 Wide belt sander BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 35

40 Competency C-3: Use Stationary Power Tools Learning Task 3 Drum Sander Drum sanders have a strip of sandpaper wrapped diagonally around a drum (Figure 4). Some models have dual drums. Like the wide belt sander, a drum sander uses a conveyor belt to feed the stock through the machine. Drum sanders are sometimes referred to as thickness sanders, and are somewhat similar to thickness planers, except they use sandpaper instead of knives. Figure 4 Drum sander Stroke Sander A stroke sander uses a very long belt above a movable table. The table is adjusted so that the stock to be sanded is a little below the sanding belt. The operator moves the table back and forth with one hand. With the other hand, they push a pad down on the inside of the moving belt to sand the stock. Some models have a safer method that mounts the pad on track. A handle allows the operator s hand to be outside the belt (Figure 5). 36 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

41 Competency C-3: Use Stationary Power Tools Learning Task 3 Figure 5 Stroke sander with lever-operated pad The lever system multiples the pressure on the belt to minimize operator fatigue. Disk Sander Figure 6 shows parts of a disk sander. Abrasive disk Work table Table tilt knob and gauge Figure 6 Parts of a disk sander Parts of a Disk Sander Motor The motor provides the spinning action. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 37

42 Competency C-3: Use Stationary Power Tools Learning Task 3 Abrasive Disk The disk is attached to the metal disk by adhesive or a hook-and-loop method similar to Velcro. It provides a flat, accurate, abrasive surface for sanding. Tilting Table The tilting table can be tilted from 0 (square to the face of the disk) through to 45 (sloping downward and away from the disk). Lock Knob The tilting table is held in any desired position by the lock knob. This knob is usually near the tilt scale and pointer, which you read before you lock the table into position. Using the Disk Sander Only the downward half of the disk should be used. This pushes the workpiece against the table or fence. The disk sander is ideal for rounding corners on the ends of a project while maintaining an edge that is perpendicular to the face of the stock (Figure 7). The disk sander is not a finishing sander because it leaves curved scratch marks on the stock. However, it will remove stock at whatever angle the table is set. Figure 7 Disk-sanding corners When the sander is equipped with a pivot jig, band-sawn circular pieces can be sanded into circles (as shown in Figure 8). This will result in the square edges that are needed for application of veneer edging. 38 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

43 Competency C-3: Use Stationary Power Tools Learning Task 3 Figure 8 Sanding circles with a pivot jig The disk sander will slightly true and trim mitres. In fact, when only a small amount of wood needs to be trimmed from the end of a small piece of stock (Figure 9), the disk sander may do a better job than a saw, especially if the saw tends to tear the wood. The use of a mitre gauge will aid precision in this operation. Figure 9 Trimming ends with the disk sander Sanding End Grain Accurate sanding with a disk sander requires the use of both the table and the mitre gauge. Lock the table and gauge at the desired angles. Then, holding the stock against both the fence and the table, gently press the end of the stock against the disk and move the stock back and forth along the face of the disk until the desired amount of material has been removed. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 39

44 Competency C-3: Use Stationary Power Tools Learning Task 3 Sanding Shapes Convex arcs, ovals and circles can be sanded to shape on the disk sander: 1. Rough out the shapes on a band saw. Leave no more than 1 or 2 mm to be removed by the disk sander. 2. Set the table to the desired angle for the edge of the work. 3. With the pattern marked on the upper face of the stock, sand away the waste portion until the desired shape is achieved. 4. Keep the workpiece moving back and forth along the disk to prevent overheating. 5. Test-fit often when fitting curved pieces to one another sand away only those portions that need removal. Disk Sander Maintenance and Safety Sanding disks can fly off the sander at a high rate of speed. Check that the disk is firmly attached before starting the sander. Do not stand inline with the disk. When changing the disk, remove all old glue and paper backing from the metal disk. If a waxy adhesive was used, remove it as follows: 1. Peel off the old sandpaper. 2. Turn on the sander and, while the metal disk spins, press the squared end of a hardwood stick against the disk. 3. Move the stick from the centre of the disk to the outer edge. 4. Turn off, unplug or lock out, and remove lumps of glue with a sharp scraper. Vertical Oscillating Spindle Sander The spindle sander has an upright shaft that is encased with a sleeve of sandpaper (Figure 10). The shaft (spindle) spins and travels up and down (oscillates). This type of sander is ideal for sanding inside curves. Steel spindles are threaded into the drive mechanism. The spindles have a rubber sleeve. Rubber and sandpaper sleeves are available in various diameters for sanding different inside radii. Sandpaper is slid over the rubber sleeve and then a nut is tightened at the top of the spindle. This compresses the rubber and puts tension against the sandpaper, holding it in place. Several insert rings are available to match different size spindles (Figure 11). 40 BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2

45 Competency C-3: Use Stationary Power Tools Learning Task 3 Figure 10 Vertical oscillating spindle sander Figure 11 Sanding spindles Types and Sizes of Grits for Sanding Disks and Belts Successful sanding depends on selecting the right abrasive for each job. In order to do this, you must have a thorough knowledge of the many types and sizes available. Sandpaper is made by gluing abrasive to a backing. The abrasive is manufactured in different grits and from different minerals, and the backing itself comes in various materials. Each of these components has characteristics that affect the sandpaper s performance. The minerals on the backing cut the wood. There are five basic kinds; three are found in nature and two are synthetic. BC CARPENTER APPRENTICESHIP PROGRAM LEVEL 2 41