Brushless Tools


Tool Guide


The principals that make brushless battery tools more efficient apply to many other electric tools as well. So a good starting place is to understand the concepts involved.


Electrical Energy for a cordless tool is stored in the battery. Batteries come in many sizes but all hold a limited amount of energy. 

Load is anything that consumes electrical energy. Drills, lights and radios are all examples of a load. 

Work is using the energy stored in the battery to carry out a task requiring electrical energy. 

Power is the rate at which electrical energy is transferred from battery while doing work. 

Consumption is the amount of electrical energy removed from the battery by doing work.

Consider the obvious, drilling a ¼” diameter hole requires a lower load than drilling a 2” diameter hole. The ¼” hole uses less power and consumes less of the electrical energy stored in the battery.

So how does this apply to Brushless Tools? If we think in terms of a car, energy stored in petroleum is converted by combustion to mechanical energy to rotate the wheels and drive the car. Everything between combustion that takes place in the engine and wheels on the road has some amount in intrinsic resistance we will call friction. A portion of the mechanical energy must overcome the friction encountered between combustion in the engine and the wheels on the road. Bearings and lubricants are used to minimize friction, but less than 100% of the energy that was stored in the petroleum makes it all the way to the wheels.

Return our attention to electric woodwork tools. Brushes conduct electrical current between stationary wires and moving parts, most commonly a rotating shaft. They are spring loaded carbon blocks that rub on a commutator that is connected to the armature of a motor. Rub is the key word here, because it produces friction. Unlike a car, lubricants cannot be used to reduce the friction. In a corded tool electrical energy is unlimited, so no problem. But remember batteries hold a limited amount of energy. So, like the car analogy, some of the energy stored in the battery is used to overcome friction caused by the brushes. Solution: Use Brushless motor technology for battery powered tools. This truly is the next generation of cordless tools. A greater percentage of the electrical energy stored in the battery is used to do actual work, drill a hole, cut a board, etc. Another way to look at this is brushless tools have longer run time between battery charges. Plus there is an added bonus, State of Charge gauges have been added to batteries in these next generation tools. By simply pressing a dot on the battery 1, 2, 3 or 4 lights will illuminate to show how much electrical energy remains in the battery. Now that’s cool.

So how do these principals apply to other electric woodwork tools? We need to put heat into the mix to understand this. When load increases more heat accumulates in the motor. Some heat is OK, but overheating a motor is not advised. Nothing good will come from it. A thin kerf blade removes less material than a full kerf blade, less work is being done to cut a board, load and heat accumulation is less. Same is true of a sharp blade and a dull blade. Think of a dull blade as an unnecessary increase in load and heat accumulation. For some reason many woodwork machine motors do not have thermal overload protection. Keeping the blades sharp is a good way to deal with this plus, you will get better results and be able to spend your shop time on more enjoyable things than sanding poor quality cuts.