Table Saw Training
Although the table saw is one of the most useful machines in the wood lab and one of the most used, it is also one of the most dangerous. You will need to become comfortable using the table saw because you will encounter it in any manufacturing setting. 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 re-sawing, however, other machines can do these operations more efficiently and safer. Use alternative machines for special operations whenever possible. With special jigs, the table saw can be used to accurately produce a number of different joinery cuts. In addition, the blade can be tilted for cutting bevels and miters.
The table saw in OCW and KBW uses a 10”diameter blade and tilts left (that is, away from the fence). Not all table saws tilt to the left, Delta for example produced many saws that tilt to the right, creating a dangerous pinching situation during bevel cuts. SawStop saws are equipped with a safety system (flesh sensing technology) 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. However, wet wood or sometimes treated wood can trigger the safety system, resulting in a false positive response. Wet wood and treated wood should not be cut on the SawStop.
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 releases 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 and in most cases the blade will also be damaged. Replacement of brake and blade could cost up to $200. Changing a brake cartridge is fast and easy – no more complicated than changing the blade. The brake ccartridge must be installed properly, approximately 1/8” away from the blade.
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.
Table Saw Rules:
- The number one accident on the table saw is kickback, which is not prevented with SawStop technology. Kickback occurs when the work piece becomes so tightly trapped between the blade and the fence the work piece is forcibly ejected back, towards the operator. Kickback can also occur when the teeth at the back of the blade ‘lift’ the stock straight towards the operators face. The chance of kickback can be reduced by using a riving knife and kickback pawls - leave these safety devices in place. The best way to help to prevent kickback is to learn to recognize the potential for the situation to develop. Common causes include material bowing during cutting, or material drifting away from the fence during cutting, or using the fence and the miter gauge for crosscutting narrow pieces.
- Table saws make cuts parallel to the fence while ripping, resulting in two parallel edges. Consider this basic fact before performing your operations. Do not attempt tapered cuts. During cutting, the blade must project about ¼” above the work.
- Do not perform any ‘freehand’ operations. A freehand operation is defined as one when the material is not supported or guided by the fence or the miter gauge.
- The fence is only used during ripping operations. The miter gauge and cross-cut sled are only used during cross-cutting. Misuse is a recipe for kickback.
- You must use a push stick when you are ripping material narrower than 5”. You must push material past the back of the blade before stopping the cut. Material left touching the back of the blade may produce a kickback.
- Material must have at least 1 straight edge (jointed) and one relatively flat face to be cut on the table saw. Crooked or bowed edges cause material to shift during cutting and could result in a kickback. If stock has a slight bow, place bow facing down.
- Any adjustments to blade tilt or height should only be made while the blade is off and stopped. Blade changes or maintenance should only be performed after the saw is unplugged.
- When you are acting as a helper for cutting long stock, you do not pull the stock, only support it so it does not fall or tilt during the operation. Only the operator controls feed speed.
- If the blade guard must be removed, you must install the riving knives. Operations that require the riving knife to be removed during the cut are not allowed in OCW.
- Never move stock backward while the blade is moving. If a situation develops where you can’t complete the cut, stop the saw with your knee while holding the stock in place, wait until blades stops, then remove the material.
- The fence and miter gauge can never be used simultaneously unless the miter gauge is between the fence and the blade, or a stop block on the fence has been installed well ahead of the blade. This setup allows plenty of room for cutoffs to ‘hang-out’, but not become trapped between the fence and the blade. Ask if you don’t understand this setup.
Never use this setup on the table saw.
- Be sure to use a proper stance while cutting. A proper stance is one that places the operator to the left of the stock (in case of kickback) and allows the operator total control of feeding the stock through the machine. The operator should use the left hand to hold the stock against the fence and down onto the table. The operator’s right hand feeds the material into the blade at a speed appropriate for the cut- not too fast, not too slow.
- Because of the weight and size of large panels (plywood), proper technique and skill must be used with an auxiliary outfeed table. Consider the operation carefully before beginning. If possible, use a buddy system (or the panel saw).
- Before starting a cut confirm that the fence is locked into position. This sounds obvious, but if the fence shifts during cutting, a kickback or some other incident is sure to happen.
- Do not attempt to rip stock shorter than 12”.
To complete the tablesaw training, you must read the available manual specific to the sawstop machine and watch the video about kickback.