I received this rock drill and used it for less than 15 minutes before it stopped working. This stopped the hammer blows and made the motor sound like an old cordless tool when it ran out of power. It didn't smoke or give off a strong odor, so I left the tool on for about an hour and it started working again. After about 30 seconds of running, he did the same thing again. I wasn't leaning heavily on the tool or trying to make it work. This is one of the Makita tools made in Japan and I expected high quality from it. I had to split the concrete by hand and use my old hole punch and lost several thousand hours of work. I ended up going back to Bosch as I've had good luck with their hammer drills in the past. Makita has traditionally been a great brand for me and it's disappointing that they put out a product with such a poor design. I will not buy their products again in the future.