February 28, 2022

How do table saws detect fingers?

Table saws detect contact with skin. The blade carries a small electrical signal, which the safety system monitors. When the skin contacts the saw blade, the signal changes because the human body is conductive. The change to the signal activates the safety system.

How does a table saw detect a finger?

The SawStop senses an electrical current in the finger. Gas is induced for electrical current onto the saw blade. If the saw nicks a finger, within 3/1000ths of a second, it fires a brake that stops the blade.

There is a little sensing device inserted inside the table saw. When the gas demonstrates how the saw table uses a hot dog as a finger, the blade disappears into the table.

The invention was necessary, due to people suffering amputations,  getting their hands mangled using table saws. More than 30,000 people ended up in emergency rooms with injuries, although minor. That is how a safety brake was figured, to prevent those accidents.

Can a bandsaw cut your finger off?

Yes, a bandsaw can cut a finger off, all the way through the bone skin holding it on. Do not place your fingers close to the saw blade when cutting stock. Always maintain a 4 inch margin of safety. If it is necessary to back the saw out of a cut, turn the power off and wait for the blade to stop.

It does not hurt much, but it feels like the wood has kicked back and hit the finger. The incident is quick, sharp, and vicious. It feels like you have been hit by a hammer.

How many tables saw accidents per year?

Over 30,000 table saw injuries occur in a year. Fingers and hands are the most injured body parts, and lacerations are the most common injury. About one in 9,000 will go to the emergency room in any given year.

Each year, more than 67,000 people are injured by table saws, resulting in more than 4,000 amputations. 

Can you put a SawStop on any table saw?

No. It is not practical to retrofit other manufacturers’ table saws. The structural changes necessary to incorporate the safety system into another saw and the installation costs are more than a new saw.

SawStop is the only table saw available for purchase that features a flesh-triggered active safety device. That is the only active safety device for a table saw that can be retrofitted onto an existing table saw.

What is the required guarding for a table saw?

Blade guards are required on table saws whenever ripping or crosscutting. Some OEM guards on low-end saws do not work very well because they secure the saw behind the blade with a thin metal blade called a splitter to help prevent kickback.

Stand to the side of the saw blade to avoid injury due to kickback. Guide the wood to be cut parallel to the rip fence to minimize the potential for kickback. Safe table saw operation is dependent on a three-part guarding system.

Does SawStop ruin the saw?

Coming in contact with the spinning blade results in a minor cut. However, if your hand moves into the saw blade at a very high speed, you can receive an injury. However, it does nothing that could damage or destroy the saw blade. 

SawStop drops the blade and rams an aluminum block into it to stop it from spinning. That destroys the cartridge assembly containing the block, and damages or destroys the saw blade. The table saw features a patented automatic braking system that stops the blade upon contact with skin.

SawStop saws absorb the force of activation and are not damaged by it. The SawStop uses the kinetic energy of the rotating blade to retract the blade.

How does a blade brake work?

The blade carries a small electrical signal. When skin contacts the saw blade, the signal changes. That is because the human body is conductive. The signal change activates the safety system. The flow of electricity reverses when the trigger is released. 

Reversing the electrical flow throws the motor into reverse long enough to provide the friction needed to stop the rotating blade. That is how the saw blade stops much more quickly than it would on its own.

When the brake is triggered, the blade stops spinning. It does not drop beneath the table, and it does not get pushed into a brake pad. All you have to do after the brake is thrown is restart the saw.

How does a table saw blade guard work?

It keeps the kerf of the cut open. This prevents the workpiece from pinching the blade or contacting the rear, rising teeth of the blade. If that happened it would cause the saw blade to throw the workpiece back at the operator. The process is known as a kickback.

It prevents wood from falling on a spinning blade. That can happen in different ways. The purpose of a blade guard is not just to keep your fingers from touching the saw blade. While it reminds you to keep your hands away, the blade guard keeps you from dropping the workpiece on top of the saw blade.

Some woodworkers remove the blade guard as it distracts the view and leads to inaccurate cuts. If you are to get the hang of operating a table saw, you should keep the blade guard on.

What table saw stops touching skin?

SawStop is an American table saw featuring a patented automatic braking system that stops the blade upon contact with skin or flesh.

What is a table saw on a Featherboard?

A feather board is a safety device used with stationary routers or power saws such as table saws or bandsaws. It applies pressure against a workpiece, keeping it flat against a machine table or fence.

What is a kickback on a table saw?

Kickback is a situation when wood gets picked up by the blade and gets thrown at you, which happens way faster than you can react. It happens when the workpiece pinches the blade or gets stuck between the blade and the rip fence.

A board can kick back during a rip cut when it goes halfway through the saw, and the kerf starts pinching the blade. That will lead to the stalling of the saw. If your table saw is powerful enough, the saw blade can throw the board right at you or flip it up and hit you in the face.

A workpiece can also get stuck between the rip fence and the back of the blade. As the blade spins, it can throw the workpiece back at you. Avoid this by making sure that the saw fence of your table saws to the saw blade.

When a piece of wood contacts with a tooth at the back of the blade. It gets lifted on top of the saw blade and thrown back at you with great force. Your hand can get drawn into the saw blade and cause an amputation. That also takes place faster than you can react.

David D. Hughes
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