Circular Saw

Overview

A circular saw makes straight cuts in lumber and sheet goods with a toothed rotating blade. This is a cordless model: an 18 V brushless motor drives the blade through a single gear reduction, and depth and bevel of cut are set by adjusting the base plate against the body. Carbide-tipped teeth and a 5,000 rpm arbor let it crosscut and rip framing stock and plywood on the jobsite without a cord.

Power comes from the Battery Pack, a slide pack of ten lithium cells managed by a protection board. The Control Electronics reads the trigger and lock-off button and commutates the Brushless Motor, whose pinion feeds the Gear Reduction. The reduction turns the arbor that carries the Blade Assembly, where the Carbide Saw Blade is clamped between flanges by the arbor bolt. Releasing the trigger triggers an electric brake that stops the blade in a fraction of a second.

Construction

The saw is built on a glass-filled nylon clamshell that carries the motor and forms the handle. The motor pinion meshes with a helical reduction gear on the arbor, both running on ball bearings. Blade depth and angle are set at the Base Plate (Shoe), a stamped-aluminium base plate with bevel and depth mechanisms that pivot and slide against indexed scales and lock with cam levers.

Guarding and safety dominate the rest of the build. The Blade Guard pairs a fixed upper guard with a spring-loaded lower guard that retracts as the saw enters the work and snaps back over the teeth as it leaves. A Riving Knife follows the blade to hold the kerf open and resist pinching and kickback. A motor-driven blower clears chips from the cut line, an LED lights the line, and a rip fence guides parallel cuts along an edge.