My cordless drill keeps dying mid-project - battery or motor?

Hey all, been having this issue with my 18V cordless drill. It works fine for a few minutes, then just cuts out like it's dead. But if I leave it for a bit, it starts again. I've tried swapping batteries (I have two), and it does the same with both. Any ideas? Could it be the motor overheating or something? I'm in the middle of a big project and this is driving me nuts.

Classic symptom of a thermal cutout or maybe a faulty trigger. If it starts again after cooling down, it's likely overheating. But check the batteries - are they old? Might be the cells sagging under load. Also, clean the chuck and make sure it's not binding. My old Makita did that, turned out a bent chuck key was causing resistance. You might also try running it at lower speed for a bit and see if it lasts longer.

What brand is it? Some cheap ones have weak thermal protection. Also, if you've got a brushed motor, the brushes could be worn out. It'll arc and heat up, then cut out. I'd check the brushes first - they're cheap to replace. Also, vacuum out the motor vents, dust buildup can cause overheating. And make sure you're not using a battery that's too low - some tools cut out when voltage drops.

I had a similar issue with a drill that turned out to be the switch. The contacts were pitted from arcing, and it would overheat and shut down. Replaced the switch, good as new. Also, check if the drill has a clutch - if it's set too tight, it might be slipping and causing extra strain. But if it's intermittent, I'd lean toward thermal protection, especially if it happens after heavy use. Try running it with a fan on it next time to see if it lasts longer.

Thanks for the suggestions! It's a DeWalt, about 3 years old. I'll check the brushes and vents. The clutch is set to drill, so that's not it. But the fan idea is worth a try - I'll see if it helps. Appreciate the help, guys. I'll report back if I find the culprit.