Why Does My Drill Bit Keep Slipping or Stopping?
Most slipping comes from a chuck that is not gripping the bit: it is loose, dirty, worn, or holding a smooth or mismatched shank. Most stopping comes from the clutch ring set too low, a bit that is binding in the hole, too much pressure, or a weak battery. Work out which of these you have, then fix it in the order below.
Greenworks DD345
DEWALT DCD777D1Best overall
BLACK+DECKER BLD782D1First, work out which problem you have
"Slipping or stopping" covers several different faults, and each has a different fix. A quick look at what actually happens saves a lot of guessing.
Watch the bit and the chuck at the moment it fails. If the bit turns while the chuck stays still, the chuck has lost its grip. If the chuck and bit both stop but the motor keeps whirring or clicking, the clutch or a stall is the cause. If the bit slides out of the front of the chuck, it was never gripped squarely.
| What you see | Likely cause | First thing to try |
|---|---|---|
| Bit spins inside the chuck jaws | Loose chuck, debris in the jaws, worn jaws, or a smooth shank | Open the chuck, clean it and re-tighten firmly |
| Bit pulls out or falls out | Bit not seated, chuck not tightened, or the bit is bent | Insert the bit fully and tighten at more than one point |
| Drill clicks and the bit stops turning | Clutch ring set too low, or you are in a drilling job on a screwdriving setting | Move the ring to the drill symbol |
| Motor slows and stalls in the hole | Too much pressure, dull bit, or a bit that is too large for the drill | Ease off, clear the chips and use a sharp bit |
| Bit slips out of a screw head | Wrong bit type or size, or too little downward pressure | Match the driver bit to the screw |
Fixing a bit that spins in the chuck
Start with the simplest cause. Wood dust, plastic shavings and metal chips can pack between the jaws and stop them from closing evenly on the shank. Remove the battery, open the jaws fully, and knock or brush out any debris.
Next, tighten properly. With a keyless chuck, hold the rear collar steady with one hand and turn the front sleeve firmly with the other. Many people stop at the first click or at hand-tight. Give it a final firm twist, then try again after the first few seconds of drilling, because vibration can let it settle and loosen.
If the bit still spins, look at the bit itself. Round, polished shanks are harder for three jaws to grip than hex shanks or shanks with flats. Check the shank for wear, rust or a smooth, shiny patch where the jaws have been slipping.
- Remove the battery or lock the trigger before touching the chuck.
- Open the jaws all the way and clear out dust and chips.
- Insert the bit so the shank sits deep between the jaws, not just at the tip.
- Tighten firmly, then tighten again with the drill held upright.
- Inspect the shank. Replace a bit with a rounded, scored or bent shank.
Why the bit falls out
A bit that falls out is usually not centered between the three jaws. If the bit is cocked to one side when you tighten, one jaw holds it and the other two barely touch. Open the chuck a little wider than the shank, seat the bit straight, and then close it.
Bit length matters too. If you insert only a short length of the shank, the jaws have little to grip. Push the shank in as far as the flutes allow. A bent bit will also work loose, because it wobbles against the jaws as it turns.
Worn or damaged chucks are another cause. If jaws are chewed up or the chuck sleeve no longer turns smoothly, no technique will hold a bit reliably. At that point a new chuck or a new drill is the realistic fix.
Why the drill stops turning
On most cordless drills, the numbered ring behind the chuck is a clutch. It is designed to stop the chuck turning once resistance reaches a set level, so screws do not get stripped. Our best drill page notes that the drills we compare offer between 14 and 24 of these settings.
If you are drilling a hole while the ring is on a low number, the clutch will slip as soon as the bit meets resistance. You will hear a ratcheting click and the bit stops. Turn the ring to the drill symbol, which takes the clutch out of play, and try again.
Also check the speed switch. Many drills have two speeds. Low speed gives more twisting force for large bits and screws, while high speed suits small bits. Running a large bit on high speed can stall the motor. Some drills, such as the DEWALT DCD806B in our lineup, also have an anti-rotation system that shuts the tool down if the drill twists too hard in your hand. If that light comes on, release the trigger, brace yourself and restart.
Pressure, battery and bit choice
If the motor slows and the bit stops while the clutch is out of play, look at how you are working. Leaning hard on the drill makes the bit bind and the motor labor. Let the bit do the cutting with steady, moderate pressure, and back it out now and then to clear chips.
A tired battery can also make the drill stall under load. Battery energy varies across the drills we compare, from 30 Wh to 40 Wh, and a smaller or partly charged pack has less to give on tough jobs. Swap in a charged pack before blaming the drill.
The bit has to suit the job. A dull bit rubs instead of cutting. A bit that is too big for the chuck or motor will stall. For example, the AVID POWER CD316-20 has a 3/8 in keyless chuck, and its listing says it is not suited to bits larger than 25 mm. Our best drill page explains that a 1/2 in chuck suits larger bits, while 3/8 in is fine for small bits and screws.
Metal and thin sheet need extra care. Standard twist bits can grab and spin the work. A step drill bit cuts clean holes in thin material with less grabbing, and it is worth comparing if you drill sheet metal often.
When the bit slips on the screw head
Sometimes the bit slips out of the screw rather than out of the chuck. This is often called cam-out. The usual causes are a bit that does not fit the screw head, a worn tip, and too little push.
Match the bit shape and size exactly, for example Phillips against Pozidriv, and replace tips that look rounded. A good assortment makes this easier, and our best drill driver bit set page compares what each set includes. Press firmly in line with the screw and start at low speed.
Safety notes
Remove the battery before changing bits or working on the chuck, so the drill cannot start by accident. Wear safety glasses, because chips and broken bits can fly. Use hearing protection when drilling masonry or running a hammer drill for long periods.
Never hold small or loose work in your hand. Clamp it. A bit that grabs can spin the workpiece and cut your hand. Avoid loose sleeves, jewelry and long hair near the chuck. When drilling overhead or from a ladder, set your footing first, because a sudden stall can twist the drill and pull you off balance.
Frequently asked questions
Can I fix a worn chuck?
Sometimes a good cleaning restores grip. If the jaws are visibly worn, damaged or do not close evenly, the chuck is the problem and replacing it or the drill is the lasting fix.
Does a hammer setting cause bits to fall out?
It can. Hammer action adds vibration that loosens a poorly tightened chuck. Use hammer mode only for masonry, and re-tighten the chuck after the first few seconds.
Why does my drill stop only when the battery is low?
A low battery cannot deliver enough current under load, so the motor stalls when the bit meets resistance. Recharge it or swap in a charged battery.
Should I use a chuck key or hand-tighten?
Keyless chucks are designed to be hand-tightened, but give them a firm final twist. If your drill has a keyed chuck, use the key at all three holes for even grip.