In normal use, electric and cordless drills require little maintenance beyond a periodic lubrication and, after considerable use, replacement of the motor brushes that make electrical contact with the rotating commutator.
Since maintenance varies with make and model, your best guide is the ever present instruction manual that comes with most new drills.
In this article I'll cover the basic steps needed to keep your new drill running for a long time.
If no instruction manual is available to follow, make a rough sketch of the visible parts at each stage of disassembly to guide you in the reassembly.
I cannot stress the importance of this step.
More than one person has skipped this step and ended up with spare parts.
If you're not much of an artist try using a digital camera and snap a picture of each step you take, then reverse the order when putting it all back together.
This is my favored method, but the choice is yours.
Some drill bodies are of the "clamshell" type - two halves held together with screws.
You lift off the top half, leaving all internal parts in place in the bottom half.
For electric drills old grease should be removed from the gear case and replaced with grease specifically made for drill gears.
This grease is readily available at most hardware and home improvement centers.
Motor and shaft bearings should be lubricated with light machine oil unless some other lubrication is specified by the manufacturer.
Ball bearings are often permanently lubricated and sealed during manufacture and therefore require no additional oiling.
Your drill will let you know when it is need of fresh grease and lubrication: It will start become noisier during use, typically a loud squealing or screeching sound.
If possible it is always better to lubricate an electric drill well it gets to this noisy condition.
With some drills, you will have to remove the front end to expose the gear case and cover section of the handle to expose the brushes.
Some drills have brush caps on opposite sides of the body at the rear.
To replace the brushes, merely remove the caps, lift out the spring-loaded brushes, and insert the new brushes and springs.
Take care not to lose the springs.
I repeat , take care not to lose the springs.
Watching a spring launch into the dark recesses of your garage or basement can really put a damper on your efforts.
Also remember to replace both brushes at the same time Basic maintenance on a drill is not particularly challenging.
It requires a bit of preparation and patience.
The end result is a drill that will more than pay for itself versus you having to pay to replace it.