As woodworkers and DIY home-improvers, we live in an old-tech world that occasionally benefits from high-tech improvements. One of the most important and interesting developments is the introduction of brushless motors into portable power tools. Companies such as Festool, Hitachi, Makita and Milwaukee have recently rolled out, or are close to releasing, cordless power tools with brushless motors.
|Hitchi's 14.4V 3.0Ah Lithium Ion Brushless Impact Driver (WH14DBL)
||Makita's 18V LXT Lithium-Ion Cordless 3-Speed Brushless Motor Impact Driver Kit (LXDT01).
I‘m not qualified to explain the technical details of how each of these types of motors work, but in a nutshell: In a typical motor, there are permanent magnets mounted on the outside and a spinning armature or rotor contains an electromagnet on the inside. The poles of the electromagnet are repeatedly changed to keep the rotor spinning. A mechanism called a commutator rubs against the metal parts called the brushes to change the polarity flow.
In a brushless motor, the arrangement is reversed; the permanent magnets are inside (on the rotor) and the electromagnets are moved to the outside. A computer replaces the commutator and brushes as the means of charging and changing the poles of the electromagnets. The advantages of brushless motors include the potential for reduced tool size and weight, significantly more power and greater durability (Check out the extreme tests this guy puts his Festool drill through in the video below. Note: We had nothing to do with this test and do not know the source). On the downside, it costs more to buy a tool that uses this technology, and there are few products available at this time.
Last summer, at an event sponsored by Milwaukee Electric Tool, I had the opportunity to use a prototype (actually, a demonstration “mule”) 18-volt cordless drill powered by a brushless motor. I was able to compare it to an 18-volt cordless drill from a well-known competing brand, an 18-volt Milwaukee cordless model (with a traditional type motor) and a corded Milwaukee drill.
|This is a graphic for the soon to be released Milwaukee M18 FUEL line, highlighting the (1) brushless motor, (2) REDLITHIUM battery pack and (3)REDLINNK PLUS communication hardware between tool, battery and charger.
All the drills were fitted with a large ship-auger bit (sorry, but I don’t remember the exact diameter) and the challenge was to bore holes in 6x6 treated lumber. To say that I was amazed by the performance of the brushless-motor drill would be an understatement. It was easily as powerful as the corded drill, and it had no trouble boring quickly through the treated 6x6. On the other hand, both of the conventional cordless drills stalled far before completing their holes. Milwaukee will be releasing its first brushless-motor tool -- an 18-volt hammer drill/driver -- in January.
For now, you’ll pay a premium for tools with these motors, but as they gain wider acceptance, they’re likely to become more affordable. Guys who torture their tools may not want to wait. Although I can’t condone abusing a tool like the tester in this video does to a Festool drill (Festool video link), it will give you an idea of how much cruelty a brushless motor (and equally rugged innards) will tolerate. Torture aside, I’m certainly looking forward to a time when cordless tools are smaller, lighter and more powerful than what’s currently available.
Photos provided courtesy of manufacturers.