Thompson Rivers University
Thompson Rivers University

Machine Shop Safety - Science

Machine Shop Safety - Science

General Rules

  1. No one should attempt to operate any power equipment unless they are familiar with its operation and they have authorization to do so. Students must have a full orientation and must be supervised while operating any of the machine shop tools.
  2. Do not work with power machinery unless another person is in the near vicinity. Students must be supervised.
  3. Check the machinery thoroughly before using it, prior to starting it up. Machinery should be locked out and or unplugged before attempting maintenance or repairs. See Lockout.
  4. Always wear safety glasses or safety glasses with a face shield while using any tool.
  5. Never wear ties, gloves, or loose clothing when working with power tools. Roll up long sleeves. Tie back long hair.
  6. Use safeguards as designed on all machines. All moving drive mechanisms should be enclosed.
  7. Pay attention to the work. Do not talk to other people while operating the machinery and do not fool around with the equipment.
  8. Keep your fingers clear of all cutting tools or moving devices.
  9. Stop the machine immediately if some odd noise or vibration develops. Investigate the source of the problem and do not operate the equipment until the trouble has been corrected.
  10. Never use your bare hands to remove chips, shavings, or other material from your work. Use a brush or push stick.
  11. Clean oil and grease from around the work area.
  12. Put all oily waste in a closed container, away from flammables. Empty this container at the end of each day.
  13. Report all accidents immediately to your instructor or supervisor. Get prompt medical treatment (Health Nurse or First Aid) for any injuries.

Drill Press

Pre-Operation

  1. Safety goggles or glasses with side shields must be worn to prevent the eyes from being struck by flying chips. It may also be necessary to wear a face shield. Eye protection must be worn under the face shield.
  2. To guard the operator from contacting the spindle, a plastic or mesh shield can be used. When necessary, a telescoping guard that covers the end of the tool can be used.
  3. Using dull drills is a frequent cause of bit breakage. A thin drill may also break and cause injury. Ensure that the drill bit used is the proper on for the job.
  4. The drill's head and arm, as well as the work must be securely clamped.
  5. Catching, hair, skin, clothing or gloves in the revolving parts is a common hazard when working with a drill press. Remove all jewelry; do not wear gloves or loose clothing when operating this piece of equipment.
  6. Sweeping chips or trying to remove long spiral chips by hand must be avoided. Use a stick for this purpose.
  7. Ensure that the key or the drift is not left in the chuck. If the drill press is turned on, the key or chuck will become like a missile with great velocity.
  8. Failing to replace the guard over the speed change pulley or gears can cause entanglement in the gears. Be sure that prior to starting the equipment that all guards are in place.
  9. The table must be secure and set to desired height and angle prior to commencing work. A loose table can cause the bit to jam, sending the workpiece into high-speed rotation.
  10. The drill bit must not be allowed to cut into the table. A spacer board can be used if necessary for this purpose.
  11. Drill bits with a screw point are to be used for a hand brace only. When used with the drill press, the point will feed in at too fast a rate and jam the bit into the work. Also, when you lift the bit out of the work, the screw point lifts the work off the table and continues to drill.
  12. The work area must be kept orderly. Tripping over debris into the rotating parts from on untidy work area could happen. The drill press will grab any loose materials and tighten them around the revolving parts.

Operation

  1. Do not feed the bit too quickly into the work. Too fast a feed can cause the bit to jam and possibly break.
  2. The work should be firmly held. If the work is too small to hold safely by hand, it should be held by a vise or held between tow pieces of wood or metal (depending on the material being drilled)
  3. When deep holes are drilled, frequently remove the drill and clean out the chips. If the chips are allowed to collect, they may jam up the bit, freeze in the hole and then break. Furthermore, a frozen tool may cause unclamped or insecurely clamped work to spin and injure the operator. The bit does not need to be raised clear of the hole in order to do this. It is actually better that you don't as you run the risk of having the work move while the bit is out.
  4. Power must be disconnected and locked out prior to making any changes or adjustment son the drill press.
  5. When using the sanding drum on the drill press, the operator and others in the area should wear a dust mask.
  6. When turning off the power to leave the equipment, always ensure that the drill has come to a complete stop before leaving. The chuck should never be stopped by hand, but allowed to stop on its own.
  7. When you change bits on a drill press, remove the key from the chuck before you go to get a new bit. Get into the habit of only letting go the key when you put it back into its place of storage.

Angle and Pedestal Grinders

Pre-operation Checklist

  1. Always wear eye protection. (Safety glasses under a face shield).
  2. Remove ties, rings, watches and other jewelry. Long hair should be tied back and loose sleeves should not be worn. Do not wear gloves when operating a buffing, grinding or polishing wheel.
  3. Make sure the wheel guards are in place and properly adjusted and tightened.
  4. Don't adjust a grinder when it is running.
  5. Blotter and wheel flanges used to mount the grinding wheels onto the shaft of the grinder must be in place.
  6. Tool rests must be adjusted and tightened to ensure that there is less than a 1/8-inch gap from the wheel.
  7. Wheels should be inspected prior to turning on the power. Wheels with cracks or chips or that are badly rutted should not be used. They may require dressing or permanent removal from service.
  8. Check that the speed rating of the grinding wheel is equal to or exceeds the speed rating of the grinder. The maximum approved speed stamped on the wheel blotter should be checked against the arbour speed of the machine to ensure that the safe peripheral speed is not exceeded.

Operation

  1. Stand to one side of the wheel when turning on the power.
  2. Before commencing grinding, allow the grinding wheel to run at operating speed for at least one minute.
  3. When commencing a grinding operation, bring the object into contact with the grinding wheel slowly and smoothly avoiding impact or bumping motions.
  4. Move the object being ground back and forth across the face of the wheel as this prevents ruts or grooves from forming.
  5. Dress the wheel on the face only. Dressing the sides may cause it to become too thin for safe use.
  6. Use the face of the wheel when grinding. Do not press too hard on the wheel.
  7. Vibrating wheels should not be used. They must be dressed or replaced or the bearings of the shaft replaced if they are worn.
  8. Do not touch the ground portion of the workpiece until you are sure that it is cool.
  9. Shut off the power and do not leave until the wheel has come to a complete stop.
  10. Clean the work area when finished using the grinder.
  11. Disconnect angle grinders from the power source when making repairs or changing discs.
  12. Pedestal grinders-turn off the power switch and lockout the electrical switch before doing any repairs.

Wheel Dressing Procedure

  1. Wear a face shield over your safety glasses for protection against heavy particles.
  2. Use a dressing tool approved for the job.
  3. Inspect star dressers for loose shaft and worn disks.
  4. Round off the wheel edges with a hand stone before and after dressing to prevent the edges from chipping.
  5. Use the work rest to support and guide the tool.
  6. Use a tool holder if one is available.
  7. Apply moderate pressure slowly and evenly.
  8. Always apply diamond dressers at the centre of slightly below the centre, never above.

Band Saw

Pre-Operation

  1. Safety glasses or goggles must be worn. If a face shield is required, safety glasses or goggles should be worn under it.
  2. Do not wear any clothing or jewelry that can catch on parts of the saw blade. It is good practice to remove all jewelry prior to using the saw.
  3. When hand feeding, the operator's hands will be close to the blade, therefore a push stick must be used.
  4. The band saw wheel and all working parts of the blade must be enclosed to prevent contact points.
  5. Ensure that the blade is in properly installed. The teeth of the blade should point downwards as it goes through the table.
  6. The saw will have a tension guide, which must correspond with the width of the blade.
  7. While the blade cannot be completely covered, the adjustable blade guard should be installed as close as possible to the workpiece. This will prevent contact with the front and sides of the blade.
  8. The guard that forms the curvature of the feed rolls should cover the nip point. This guard should be installed so that the edge is 9 mm from the plane that is formed by the inside face of the feed roll in contact with the stock.
  9. The upper blade guide must be adjusted so that it is 6 mm above the work.
  10. Check the blade to ensure that it tracks properly.
  11. Clear away all materials from the table and around the saw.

Operation

  1. The blade must reach full speed before cutting.
  2. Feed the stock at a moderate speed. Do not force the cut.
  3. Make several relief cuts before attempting a sharp curve cut. This prevents the sawblade from binding and possibly breaking the blade or causing it to jump of the wheel guides.
  4. Plan cuts to avoid having to back out of long, curving cuts.
  5. Before backing out of a cut, shut off the saw and allow it to come to a complete stop. A band saw may coast for a long time.
  6. The operator or another person should never stand on the right hand side of the table. If a blade breaks it will fly off to the right. Broken blades should be changed only when the power has been shut off and the saw has come to a complete stop. The equipment should be locked out when a blade is being changed or other maintenance work is performed.
  7. Sharp curves should only be cut with a narrow blade.
  8. Do not twist or apply pressure to the blade.
  9. Clear material away from the table only with a stick. Never remove material from the table with your hands.
  10. A clicking sound indicates that the blade could be cracked. Shut off the power and lock out the equipment prior to changing the blade. Change the blade if necessary.

Band Saw Crack Limits

Band Saw Width Maximum Length of Crack
Millimetres Inches Millimetres Inches
Up to 125 Up to 5 1/10 of saw width 1/10 of saw width
125 to 300 5 to 12 13 1/2
Over 300 Over 12 19 3/4
  1. A band saw with a crack exceeding the limit specified in the above table must be removed from service until the crack is repaired and the saw retensioned by a qualified person
  2. A band saw with a crack not exceeding the limit specified in the table must be removed from service until the crack is repaired or the lengthening of the crack has been arrested by centre punching or other effective means and the saw re-tensionned as required.
  3. A shake band saw with a crack cannot be used.
    1. Unless otherwise specified by the manufacturer or a professional engineer, the minimum rim thickness of a cast steel band saw wheel measured 25 mm (I inch0 inboard form the rim edge must be:
      • 14 mm (9/16 in) for wheels up to and including 1.8m (6 ft diameter,
      • 16 mm (5/8 in) for wheels over 1.8 m (6 ft) up to and including 2.75 m (9ft) diameter, and
      • 17.5 mm (11/16in) for wheels over 2.75 m (9ft) diameter.
    2. A qualified person must nondestructively test a wheel over 1.2 m (48 in) diameter for cracks at least once per year.
    3. A cracked wheel or a wheel which has been exposed to excessive heat must be removed from service until the wheel manufacturer, or a professional engineer, has certified it as safe for continued use. Never leave a running saw unattended. When you are finished using the saw, wait until the blade comes to a full stop before leaving the equipment. With a band saw, especially a large one, this may take some time.

Lathe

Operation

  1. Safety glasses or goggles must be worn. A face shield and/or dust mask is also required if the operation is dusty.
  2. A person using the lathe must have prior instruction. Students must be supervised.
  3. Operators should carefully inspect all parts of a lathe for defects before starting a job.
  4. Clamp your work firmly. Use the correct type and size of chuck for the job.
  5. Persons using the lathe must check that the stock does not have any checks, splits, cracks or knots. The stock must be constantly checked to ensure that it will not break during lathing.
  6. The clearance between the workplace and the toolrest should be about 1/8 inch (3mm). Hold turning chisels firmly in place in the tool rest.
  7. After adjusting the chuck, remove the chuck wrench immediately.
  8. Be sure all guards are in place around the rotating heads of the lathe before attempting to operate the machine.
  9. Use sharp tools, properly adjusted for height and position.
  10. Turn the faceplate or chuck by hand to make sure there is no binding and the work will not strike any part of the lathe.
  11. Stop the machine and unplug before making any adjustments or measurements.
  12. If metal or plastic shavings build up on the tool, stop the lathe and remove them with pliers, never with bare hands.
  13. Be careful not to run the cutting tool into the chuck or dog. Make sure there will be ample clearance on the work before starting to cut.
  14. Files must not be used on the lathe unless they are fitted with handles. The use of hand-held strips of abrasive cloth to polish the work is prohibited.
  15. Always feed the stock into the rotation of the cutter.

Milling Machine

  1. Always safety glasses or goggles with side shields. If it is necessary to wear a face shield, safety glasses or goggles must be worn underneath.
  2. Persons using the milling machine must have instruction and understand the safe operation of the equipment. Students must be supervised at all times.
  3. Always unlock or unplug machine before making any adjustments.
  4. Draw the job back to a safe distance prior to making any adjustments.
  5. Do not use a vise or jig that prevents close adjustment of the guard. Never leave the cutter exposed after the job has been removed.
  6. Do not leave hand tools on the worktable.
  7. Always securely clamp the work prior to milling.
  8. Never reach around the cutter to remove debris when the machine is in motion.
  9. Always use a brush to remove cuttings, never sweep them away with your hand.
  10. Do not adjust the flow of the coolant while the machine is running.
  11. Work should only be measured or calipered when the machine is not running.
  12. Do not use a rag to clean excess oil off the table while the machine is running. Wait until the machine has come to a full stop.
  13. Do not wear gloves, rings, ties loose hair or jewelry that may get caught in the power clamps.
  14. Ensure that cutters are correctly dressed and stored.
  15. Never remove a nut from the machine's arbor by applying power to the machine.
  16. Take care not to strike the cutter with a hand or arm while setting up or adjusting a stopped machine.
  17. Be conscious of the distances between the arbor and other parts.
  18. Never clean the machine while it is in motion.

References:

1. Teaching Physics Safely, American Association of Physics Teachers, 1979

2. Walker, John R., Machining Fundamentals; The Goodheart-Wilcox Co., Inc., 1977

3. "Occupational Health & Safety Regulation" - B.C. Regulation 296/97; Workers' Compensation Board of British Columbia, 1998