Blade elevation mechanisms and anti-backdrive mechanisms for table saws

A table saw comprising:

• a table defining a work surface;
• a substantially planar, circular blade configured to extend at least partially above the work surface;
• a motor to spin the blade;
• and
• an elevation system configured to change the elevation of the blade relative to the work surface, where the elevation system includes a handwheel adapted to be turned by a user to change the elevation of the blade by at least 3 inches with 5 turns or less of the handwheel;
• and
• an anti-backdrive mechanism configured to prevent gravity from causing the blade to drop more than a quarter of an inch when a user releases the handwheel.

A table saw comprising:

• a table defining a work surface;
• a substantially planar, circular blade configured to extend at least partially above the work surface;
• a motor to spin the blade;
• a rotatable handwheel adapted to be turned by a user to raise and lower the blade;
• and
• means for raising the blade at least 3 inches from a fully lowered position with 5 turns or less of the handwheel and for preventing gravity from causing the blade to drop more than a quarter of an inch when a user releases the handwheel.