High-Performance Li-ion Circular Saws Factory

BOSI Tools is a Li-ion circular saw manufacturer from China, offering the Li-ion Brushless Circular Saw and the Bumblebee Series Li-ion Brushless Circular Saw.

A brushless motor drives a 150mm blade at a high speed of 6,000 rpm, a lightweight 1.5 kg body features 0–45° bevel adjustment, and ultra-wear-resistant alloy gears — BOSI provides a cordless precision cutting solution for carpenters, formwork installers, and renovation sites with its 20V lithium-ion platform.

We can provide selection advice and customized solutions based on actual working conditions. Please feel free to contact us at any time.

Working Principle

The essence of a Li-ion circular saw is to convert the battery's DC electrical energy into the high-speed rotation of a saw blade via a brushless motor, performing straight-line cutting through circular tangential motion.

The BOSI Black Warrior Cool Series is equipped with a brushless motor. Once powered by the 20V/4.0Ah battery, the rotor directly drives the saw blade at a no-load speed of 6,000 rpm. The saw blade has a diameter of 150mm and a cutting depth range of 0–55 mm.

The brushless motor eliminates the mechanical friction of carbon brushes and a commutator, offering higher energy efficiency and longer service life, with high speed and high torque ensuring smooth, jam-free cutting.

The transmission system uses alloy gears that are ultra-wear-resistant, stably transmitting the motor's torque to the saw blade spindle. An aluminum base plate can be tilted from 0–45° via an angle adjustment mechanism, enabling bevel and chamfer cuts.

The Bumblebee Series upgrades this foundation with a 5030 brushless motor and a 4500mAh battery, offering a variable no-load speed range of 0–5,800 r/min, a 150mm/24T saw blade, the same 0–55 mm cutting depth, a bare tool weight of 1.84 kg, and it comes standard with two batteries and one charger.

During cutting, the carbide-tipped teeth on the blade's circumference sequentially enter the wood, with the leading edge of each tooth planing off tiny chips. The base plate is held firmly against the workpiece surface to ensure a straight saw line. The lightweight body design makes one-handed operation possible, though a two-handed grip is recommended for improved stability.

How to Choose the Right Li-ion Circular Saw?

The primary criteria for selection are cutting precision and work intensity. For panel cutting on renovation sites and stock preparation for formwork installers, the Black Warrior Series is lightweight and portable at 1.5 kg, with smooth cutting at a constant 6,000 rpm.

For professional carpenters who need variable speed adjustment to adapt to different material densities, the Bumblebee Series, with its 5030 motor and high-capacity 4500mAh battery, meets the demands of all-day operation.

The saw blade diameter and cutting depth are consistent, and accessories are interchangeable and shared between the two series.

Common Problems and Solutions

Our Li-ion Circular Saws vs. Other Brands: Why Choose BOSI?

BOSI Li-ion circular saws ensure transmission durability with an all-series brushless motor and alloy gears, and enhance portable working experiences with a lightweight body and high-capacity battery, filling the quality gap between generic brands and imported high-end products in the woodworking and renovation sector.

Safety Precautions for Use

1. Battery Safety

Use the original charger for charging. Protect the battery from high-temperature exposure and immersion in water. Store with a 30%–50% charge.

Rotate between the two batteries and one charger. Before starting work, use the one-button battery level check to check the remaining runtime.

2. Blade Inspection

Before use, confirm that the saw blade is free of missing teeth, cracks, or adhered foreign objects, and that the securing nut is locked.

The rated speed of the saw blade must be higher than the tool's no-load speed. Keep both hands clear of the tooth path while the blade is rotating.

3. Operating Posture

Hold the tool with both hands, stand firmly with one foot slightly forward, and position your body offset from the plane of the blade to prevent injury from kickback.

During cutting, keep the base plate firmly against the workpiece, and feed at a constant speed without forcing. Although the lightweight body is just 1.5 kg, a two-handed grip is still recommended during cutting.

4. Angle Adjustment

When adjusting the bevel cut between 0–45°, confirm that the locking mechanism is fully engaged, and do not allow the base plate to become loose during the cut.

Always wait for the saw blade to come to a complete stop before adjusting the angle.

5. Kickback Prevention

When cutting long boards, support both ends to prevent the blade from pinching. Never withdraw the saw from the workpiece before the blade has completely stopped, as the teeth may catch the kerf and cause kickback.

The movable guard must flexibly return to its position; tying it back to keep it permanently open is strictly prohibited.

6. Maintenance and Storage

After work, clean accumulated dust from the housing ventilation slots and the inside of the guard. If not using the tool for an extended period, remove the battery and store it separately, recharging it once a month.

Although the alloy gears are wear-resistant, it is still recommended to check their lubrication annually. Store the saw blade by hanging it or laying it flat to prevent the tooth tips from being knocked and damaged.