How does a jigsaw work?

	A jigsaw is a type of power saw that consists of a motor that drives a narrow blade with a fast up and down motion. The back and forth movement of the blade is very similar to the movement of the needle in a sewing machine.
	Inside the body of the jigsaw, the motor is connected to the blade by a set of eccentric gears (gears whose axes are off-center). These gears convert the rotary motion of the motor into a reciprocating vertical motion of the blade holder, causing the blade to move rapidly up and down.
	A jigsaw blade usually cuts in an upward motion because its teeth point upward. If a clean cut is important, you should turn the workpiece over to cut from the back of the material to prevent splitting on the front. During operation, the shoe (base) of the tool is adjacent to the workpiece. Work is attracted to the shoe as the blade cuts through the material.
	The speed of most machines can be changed using the speed controller. This feature, along with the orbital action feature, allows the user to control cutting and work with a variety of materials. High speeds are used for wood, while slower speeds are used for plastic and metal.