18v Cordless Drills

- dewalt 18v cordless impact gun not running at full power?
It's a few years old, and it gets a lot of use. I've noticed lately that even when either battery is fully charged, it's not running at full power. Could this indicate the motor brushes need replacement?

A It could, especially if it seems to hold a charge as long as it used to. Look through the vents at the back of the drill for arcing, which is usually the first sign of worn brushes or a sticky brush spring. Some cordless tools have brushes that can be replaced and some don't. Go to http://www.ereplacementparts.com with your model number to get a parts breakdown to see if yours are replaceable. Once you get it apart, take a close look at the copper contacts at the top of the armature (the thing that spins that the brushes contact) to ensure they're all the same color and none of them are burnt out. But before you do any of that, how old are your batteries? If they're also a few years old, then they probably need replacement as well, which would cost as much as an entirely new tool, and a lot more than a reconditioned one that comes with new batteries. I've been buying recons for myself and the shops I've run and have never had a bad experience. They come with the original manufacturer's warranty and I'll never buy a new power tool again. Go to http://cpooutlets.com to see what a reconditioned DeWalt impact gun will cost you and I bet it'll be a lot less than you'd pay for just a couple of new batteries from a home center or website. The brushes will cost less than $10 but the shipping will be more than that, probably, so factor that into your decision as well. After you check on ereplacement.com to see if brushes are even available for your DeWalt, take it apart and look at them to see if they're worn. But if the batteries are also a few years old, I probably wouldn't bother. This time of year you might find a new kit on sale online or at a big box store, though I'd still go with reconditioned.

- can you use an 18 volt battery on a 14 volt dirll?
I recently purchased a 14v impact drill, the two batteries hold a charge fine, but I am wondering if I can use an 18v pack instead. The 14 and the 18 both fit the drill.

A All good answers, but what it all boils down to is the motor will will not last as long running on the higher voltage. Depends on how well built the motor is. It might last just as long, or it might burn out the 3rd time you use it.