Table Saw Safety

Although the table saw is one of the most useful machines in the wood lab, it is also one of the most dangerous. It can be used to accurately rip and crosscut lumber and sheet goods. The table saw can also be used for special operations including cutting dadoes and rabbets and for resawing. With the use of special jigs, joinery like tenons and box joints can be made. In addition, the blade can be tilted for cutting bevels and miters.

The saws in SBWI use 10”diameter blades and tilt left (that is, away from the fence). All 10” saws in our wood lab are SawStops, considered the safest in the industry. SawStop saws are equipped with a safety system that detects when someone accidentally contacts the spinning saw blade, and then stops the blade in milliseconds. In most cases, such an accident would result in just a nick on a SawStop saw, instead of the devastating injury which would likely occur on an ordinary table saw.

How does it work? The SawStop electronic safety system induces an electrical signal onto the blade and then monitors that signal for changes. Because the human body has a relatively large inherent electrical capacitance and conductivity, this signal drops when flesh contacts the blade. Wood, on the other hand, has a relatively small inherent capacitance and conductivity and therefore does not cause the signal to drop when it comes in contact with the blade.

A fast-acting brake immediately stops the blade. The brake includes a heavy-duty spring that is held in compression by a fuse wire. When you touch a spinning blade, the system sends a surge of electricity through this fuse wire to burn the wire and release the spring. The spring then pushes a block of aluminum (called a brake pawl) into the teeth of the spinning blade. The blade’s teeth cut into the aluminum and bind, thereby stopping the blade. All of this happens in about 3–5 milliseconds, or 1/200th of a second. At the same time, the angular momentum of the blade causes the blade to retract below the table and the power to the motor is shut off.

Both the standard brake cartridges and the dado brake cartridges are single-use components that must be replaced if the brake is ever activated. Changing a brake cartridge is fast and easy – no more complicated than changing the blade. The brake cartridge must be installed properly, approximately 1/8” away from the blade, and should be checked by the Instructor.

The SawStop has a built-in MAIN POWER SWITCH. When you flip the switch on, red and green lights flash for approximately 20 seconds as the system runs through a safety check.

When the red light turns off and the green light remains on, the saw is ready.

To activate the blade, you will pull the red START/STOP PADDLE at the bottom. The saw can be turned off by gently bumping the paddle with your knee.

Do not use the table saw until you have been through the WMT table saw safety presentation and are personally checked out in its use by your instructor you must be checked out each semester regardless of whether you have been checked out earlier.

1. The number one cause of injuries on the table saw is kickback. Kickback occurs when the operator loses control of the material being cut and it is thrown from the machine with great force.

2. When cutting, the saw blade should project ¼” above the stock or enough to clear the common gullets.

3. The fence is used to guide ripping operations. The miter gauge or sled is used to guide crosscut operations. Always hold the work firmly against the fence, sled, or miter gauge.

4. During a rip cut, once the material has moved away from your left hand, move your left hand off the table. Do not drag your hand across the table and never reach over the blade.

5. You must use a push stick when ripping pieces that are 6” or less in width.

6. Cutting workpieces shorter than 10” in length is a special setup; get permission from the instructor or aide prior to cutting.

7. Performing on-edge resawing is a special setup. You must get specific instruction and special permission from your instructor.

8. When ripping stock, the piece between the fence and blade must be controlled and pushed past the blade all the way onto the outfeed table. Failure to do so may result in a kickback.

9. Lowering stock directly down over the saw blade is dangerous and is never allowed.

10. Procedures involving raising the blade into the work are special setups. Permission and instructions must be obtained from your instructor for doing this type of work.

11. The over-arm saw guard must always be in place over the blade except when the instructor has authorized its removal for special setups.

12. The riving knife must always be in place behind the blade except when the instructor has authorized its removal for special setups.

13. Make adjustments only when the power switch is off and the blade is at a complete stop.

14. Whenever a measurement or other procedure is made where you must have your fingers in close proximity to the blade, make sure the main power switch is in the off position.

15.The main power switch should be left in the off position when you leave the saw.

16.Freehand cutting, ripping, or crosscutting without using the fence, sled, or miter gauge is

ABSOLUTELY FORBIDDEN in all circumstances.

17.When you are ripping stock, the scrap must fall to the outside (non-bound side) of the blade (not between the blade and fence).

18.Do not reach over the saw blade or pass wood over the saw blade at any time.

19.When helping someone to tail-off (supporting the work hanging off the back of the saw table), your only purpose is to support the stock from below. Only the operator pushes thestock through the saw.

20.Make sure the blade is stopped and completely lowered when clearing scraps from the table.

21.The instructor must inspect all special setups and dado blade installations before the power is turned on.

22.Use a special setup with V-block or sled when cutting cylindrical stock to help keep it from spinning.

23.Backing the stock away from the blade while the saw is running may throw the piece toward you. If it is necessary to remove the piece, always stop the saw first.

24.Never attempt to turn off the saw in the middle of a cut. If you must stop mid-cut, stop what you are doing without moving your hands and turn off the saw by gently engaging the red START/STOP PADDLE with your knee.

25.If the fence is used at the same time as the miter gauge, the miter gauge must be between the fence and the blade. This is a special setup.

26.When you are crosscutting a number of pieces to the same length, clamp a clearance block to the rip fence well ahead of the saw blade to prevent the cut piece from being pinched between the blade and fence.

27.Stock edges or faces that contact the table, miter gauge or fence, must be straight and flat.

28.Seek assistance and direction from your instructor before milling materials with defects such as splits, warps and knots.

29.Changing the saw blade is required depending on the situation and is a special setup. The brake cartridge must be installed properly and adjusted approximately 1/8” away from the blade, and checked by the instructor.

30.Obtain permission from the instructor for all special setups using the 8” dado set, which requires a different brake cartridge installed properly [1/8” gap]. Manually spin the blade through one rotation to make sure it clears the brake cartridge before turning on the saw.