Why has my masonry drill bit stopped cutting?

The four reasons a masonry bit stops making progress — blunt tip, hammer off, packed dust, or something in the wall it was never meant to cut.

Difficulty: beginner
Time: 15 min
Read: 3 min

Short answer

Pull the bit out and look at the tip. A rounded or blued carbide tip is blunt and needs replacing. If the tip looks fine, check hammer action is engaged, clear the packed dust from the hole, and consider that you have hit a hard engineering brick, concrete lintel or a piece of aggregate that needs an SDS drill rather than more pressure.

A masonry bit does not cut in the way a wood bit does. The carbide tip chips the material and the hammer blows do the work; the flutes only carry the dust out. Any one of those three failing stops progress, and pushing harder makes all three worse.

Step by step

Stop and withdraw the bit.Leaning on a bit that is not cutting only generates heat, and heat is what destroys the carbide tip.
Look at the tip.A sharp masonry tip has two clean chisel edges meeting at a point. Rounded, chipped or blue-black means it is finished — carbide that has been overheated will never cut again.
Check hammer action is actually engaged.On a combi drill the collar has to be fully in the hammer position. Half-engaged is common and the drill will spin without percussing.
Clear the hole.Withdraw the bit fully every couple of centimetres. Packed dust at the bottom of the hole cushions the hammer blow, so the bit bounces on powder instead of striking brick.
Feel what you are drilling.A sudden stop with fine grey dust usually means concrete or a lintel. A stop with a metallic scrape means a steel lintel, reinforcement or an old nail. Chalky red dust that goes soft again is a mortar joint.
Check the drill is up to it.A combi drill's hammer is a light percussive rattle. In dense concrete or engineering brick it simply is not enough, and an SDS drill will go through in seconds what a combi will never finish.
Change the bit before you change the technique.Masonry bits are cheap and a blunt one is the single commonest cause. Try a new bit before assuming the wall is the problem.
Do not use extra pressure to compensate.Percussion does the cutting, not force. Heavy pressure stops the hammer mechanism travelling properly and reduces the blow energy.

Tips

Withdraw fully every 20mm or so to clear dust. It is the fastest fix for a bit that has slowed down.
A bit that heats up quickly is blunt. A sharp bit in a working hammer drill stays surprisingly cool.
If you hit steel, stop. Drilling a lintel's steel is a job for a proper HSS or cobalt bit, and drilling reinforcement in concrete is a decision, not an accident.

Common mistakes

Pushing harder when progress slows — Force does not cut masonry; the hammer blow does. Extra pressure prevents the hammer mechanism from working properly and overheats a tip that is already struggling.
Never clearing the hole — Dust packs into the bottom of the hole and absorbs the percussion. The drill sounds as though it is working while removing almost nothing.

If it doesn't work

Fine grey dust and no progress

Cause: Concrete or a concrete lintel — Fix: Switch to an SDS drill with an SDS bit. A combi drill will rarely make useful progress in dense concrete.

Metallic scraping, bit skidding

Cause: Steel lintel, reinforcement bar or an embedded nail — Fix: Stop. Move the hole if you can. If you must go through steel, use a sharp cobalt bit with hammer action off.

Bit hot and smoking

Cause: Blunt tip, no dust clearance, or too much pressure — Fix: New bit, clear the hole regularly, and let the hammer do the work.

Progress fine then suddenly slow at 40mm

Cause: Hit the brick behind a soft mortar bed or a hard aggregate stone — Fix: Persist gently with hammer on and full dust clearance, or move 25mm and start again.

Questions people ask

Can I sharpen a masonry bit?

In principle, on a bench grinder with a green silicon carbide wheel, matching the original tip angle. In practice bits cost little and getting the angle wrong makes them worse, so replacement is almost always the sensible choice.

Why did the bit go through the plaster easily then stop?

Plaster is soft and cuts on rotation alone. The brick or block behind needs hammer action, so this is usually the moment you discover hammer is not engaged.

Is water helpful when drilling masonry?

No, and it makes it worse. Water turns the dust into a paste that packs the flutes solid. Water is for diamond bits in tile and stone, not carbide bits in brick.