With the new lithium-ion powered drills we decided to switch to get more power from lighter drills and more holes per battery charge. We bought a new Makita, new Milwaukee M18, a new Hitachi, and a DeWalt XRP DCD970 and had our guys use them for the past two months. We learned a lot by comparing the drills. Hitachi was the quick reject as it has a chuck that drops bits all the time and has the least power and stalls the most. Makita's have long been a favorite as they hold up better than any other drill we have used over the years but their latest LXT model does not seem to really put out the power their specs would lead one to believe.
The Milwaukee M18 has the most power according to its specs and the smoothest clutch, and a great all metal gearbox, but has overly sensitive overload protection and only a 2-speed ranges. The M18 also has the same kind of side handle mount as the new Ridgid 18v drill which can only be mounted at exactly 90 degrees to the main handle. When I am drilling in very tough material and really need two hands to keep everything under control I like to have the side handle at less than 90 degrees and with the Milwaukee and Ridgid drills I can't do this.
The DeWalt XRP did not start out as anyone's favorite but after its first month of use by the different crews it is now the top choice of everyone. It’s 3-speed gearbox really makes a very big difference in performance. Number 2 and 3 settings are like 1 and 2 for other drills, the XRP has what amounts to a granny gear that delivers a lot more usable torque from the motor and battery pack.
check this out -
http://www.youtube.com/watch?v=2Jb-7fgDW_U
With the lithium-ion batteries there is a draw limit or they overheat and a safety circuit cuts out power or they discharge faster and you don't get as much useful work out of a charge. Being able to use the ultra low range on the DeWalt with large hole saws or drill bits makes a big difference and often the holes actually get cut just as fast as their is no stalling (quite noticeable with the Makita, Hitachi, and Milwaukee lithium-ion drills).
We have cut 6-1/4" holes in 1-1/8" subflooring and through stucco & OSB using the DeWalt and Blue Boar TCT hole cutters and we could not have done it any faster with a Milwaukee Hawg stud drill. Actually I prefer the DeWalt cordless as it is a lot easier to control if the drill binds up and a heck of a lot safer than the Hawg.
I have come to realize that to get the most out of a cordless drill the 3-speed gearbox is key to staying within the comfort zone of the drill motor and the battery pack. I see now that using new modern cordless drills with old fashioned hole saws and self feed bits and expecting good performance was not very bright on my part. The right hole cutter makes a huge difference in performance, and in the long run on the life of the drill. I figure if it takes 10 times as long to drill a hole by using a bi-metal hole saw or self feed bit, that this is also shortening the drill’s life by 90%. The easiest thing to do is use a modern hole cutter that puts a lot less stress on the drill and provides much better performance.
We cut a hole in 1-1/8" Sturd-I subflooring using a new Lenox bi-metal hole saw and it took a couple minutes which was no surprise and burned the wood which was also no surprise but when we recharged the M18 we had used it took more than 30 minutes to get back to a full charge. We tried using a new Milwaukee Selfeed bit and it still took 40 seconds to bore a hole through the subflooring and it too took a lot out of the battery. We had a Blue Boar TCT hole cutter that one of our guys had been using all week and I tried it out and the next hole took 10 seconds, as did the rest of the holes we cut and continued to cut using the same battery pack for the rest of the day.
Charge times for the different batteries varies quite a bit. The Milwaukee M18 takes 45 minutes, Hitachi about 30 minutes, and DeWalt and Makita both take less than 15 minutes. With DeWalt and the Makita drills we only need one spare battery pack on the job.
We have learned to use the M18 drills differently and when using "hungry" hole cutters like the Blue Boar TCT that we need to start slowly to avoid the overload protection taking over. The DeWalt XRP drills have been the best overall with one exception. The XRP chuck tends to lock up and we need to use a small pair of channel locks to loosen it. We have decided to go with the DeWalt DCD970 drills and the Blue Boar TCT hole cutters for all our trucks and after all our testing are pretty confident we are making the right choice – no doubts whatsoever about the Blue Boar hole cutters though.