Safety


Causes of tablesaw injuries include:

  • failure to read warning labels and the owner's manual before use.
  • When the saw is not in use, leaving the blade projecting above the table.
  • Not disconnecting power when performing maintenance or changing blades.
  • Not using a push stick or other such safety device when making cuts that otherwise require fingers to be close to the blade.
  • Using the saw in a way that fingers advance into the path of the blade.
  • Failing to be alert and pay consistent attention. This piece of equipment causes more serious injuries than anything else in the shop. Many experienced woodworkers know someone who have lost a finger.
  • Removing the blade guard. If the original guard is unsatisfactory, aftermarket guards are available in various configurations. Note that one main function of a typical blade guard is to act as a splitter, which helps prevent the cut in the wood from closing and pinching the back of the blade and kicking back. Sometimes the blade guard is more of a danger than a safety feature, most commonly during smaller cuts (less than 3 inches), and cuts with a push stick, and should be removed.
  • Wood being cut can violently kick back. This is due to advancing the wood in a sinuous line or because natural stresses in the wood cause the cut to pinch the back of the saw blade. This can be strong enough to cause the material to jolt backwards and result in serious injury to the operator. The use of the splitter or a riving knife can reduce or eliminate this problem.
  • Not wearing Eye protection. The rotational mass of a spinning saw blade combined with a large electric motor can contribute to the violent and unexpected ejection of material. Wearing unsuitable safety glasses that don't fully encompass the eye area, including the front and sides of the eye, can also result in injuries. Good safety glasses are comfortable so they are always worn when needed.
  • Lack of ear protection. Causes steady loss of hearing.
  • Wearing clothing that's excessively loose-fitting, and failng to tie back long hair. These are dangerous if they come in contact with the blade. Cuffs should also be buttoned if wearing a long-sleeved shirt.
  • Blade misadjusted so its not perfectly parallel with the fence and the miter slots. If it is not parallel, the workpiece can often become pinched between the blade and the fence, inducing violent kickback and causing injury.
  • Not pushing the material past the saw when finishing a cut. These pieces can get caught and violently drawn into the blade, resulting in kickback.
  • Failing to operate defensively. The nature of wood includes variations in structure and internal forces, and its not uncommon for natural stresses in a piece of wood to cause the blade to be pinched and thrown violently. So cautious working is important.

 

Avoiding kickback

Kickback happens when the blade catches the workpiece and violently throws it back to the front of the saw, towards the operator. It can be thrown very hard and can injure the operator. It is not uncommon for the object to have high enough velocity to become embedded in a wall or to cause other damage or injury. Never stand in a direct line between the blade and the fence when ripping narrow stock. A kickback can be fatal.

Kickback happens when ripping if:

1. The wood pinches the blade because of internal stresses. This is difficult to predict and can be impossible to control when using fingers to hold the wood down. Many times the board pinches the blade and is thrown back before the wood reaches a splitter. This type of kickback never happens when a board is not cut all the way through (dado). By starting a cut with a dado and then raising the blade to leave a splitter tab of uncut wood, this type of kickback can be avoided, but raising the blade during a cut cannot be done unless anti-kickback hold downs are used, so it is safe to raise the blade with a free hand.

2. The wood is allowed to raise up or moved sideways during a cut, then pushed back down, taking too big a bite at the top of the blade. This can be prevented by using feeder wheels very close to the start of the blade and hold downs after the blade to control the wood all the way through the cut. The right feeder wheels are very effective for both dados in plywood and for rip cuts on boards as narrow as 1/8". Feeder wheels can be powered or unpowered, clamped or held magnetically, and replace fingers near the blade so a hand can be free to turn off the saw during a cut.

3. The board is pinched between the rear of the blade and the fence. The fence should be parallel with the blade, for the best cut on both sides of the blade. The fence can be set with the rear farther from the fence for safety, but at the expense of upcut marks on the "waste" piece. Never allow the fence to be closer to the rear of the blade than the front.

Fire Hazard

A dust extractor should be fitted. If sawdust is prone to build up under the cutting blade, through friction the spinning blade will quickly ignite the accumulated dust, and the smoke can be mistaken for an overheated blade. The extractor also reduces the risk of a dust explosion and facilitates a healthier working environment.

New safety technologies

In recent years, new technology has been developed which can dramatically reduce the risk of serious injury caused by table saws.

One way to prevent fingers from being severed is to use springs or feeder wheels to apply pressure on the side and top of the lumber when ripping. These feather boards and push sticks are substitutes for fingers. Traditionally they are clamped to a saw top.

Blade height

There are two competing schools of thought when it comes to properly setting the height of the blade for sawing. The first is commonly expressed thus: "Only allow the blade to rise above the work by the amount of finger you wish to lose." That is, the blade should protrude above the piece as little as possible, to prevent the loss of a finger in case of a sawing accident.