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How to use a cordless angle grinder

Updated: October 2026

You have the grinder out of the box, a disc still in its sleeve, and a bracket held in your spare hand. The snatch people fear usually starts earlier than the cut: the battery is still on, the guard is loose, or a cutting disc is asked to grind. This is how to use a cordless angle grinder, and where the same wheel becomes an employer's duty at work. Model ranking stays on the [cordless angle grinder comparison](/hub/sanders/cordless-angle-grinder). Which class of tool you bought is the [buying guide](/hub/sanders/cordless-angle-grinder/sub/cordless-angle-grinder-buying-guide). Which disc belongs on steel is the [cutting metal page](/hub/sanders/cordless-angle-grinder/sub/cordless-angle-grinder-cutting-metal).

You have the grinder out of the box, a disc still in its sleeve, and a bracket held in your spare hand.

Our top picks

Ryobi Ryobi R18AG-0 115 mm bare

Best overall

Ryobi Ryobi R18AG-0 115 mm bare
9.4/10about £66.65
View offer
DeWalt DeWalt DCG407N-XJ 125 mm bare

Rank 2

DeWalt DeWalt DCG407N-XJ 125 mm bare
9.4/10about £107.50
View offer
DCA DCA ADSM06-125 125 mm kit

Best value

DCA DCA ADSM06-125 125 mm kit
8.6/10about £56.98
View offer
On this page
  1. 1.Before the disc turns
  2. 2.Guard and both hands
  3. 3.A short cut, then stop
  4. 4.Eyes, ears, and work versus home

Before the disc turns

Take the battery off before you touch the flange. Corded advice says unplug, and that still matters for the charger: Electrical Safety First expects a UK 3-pin plug on the tool or the charger, and says not to buy a damaged second-hand tool. On a cordless body the first step is the pack. With the battery off, read the maximum speed marked on the wheel under EN 12413. If that maximum is below the grinder, the wheel does not go on. Seat the disc between the correct flanges, tighten with the spanner, and take the spanner off before you think about the switch. One DeWalt buyer in this set was sent the wrong key and could not change the disc. If the pin does not lock the spindle, stop and sort the key. A cracked disc belongs in the bin.

Guard and both hands

The guard stays on. Hilti's UK notes for a 125 mm grinder distinguish the guard position for cutting from the guard position for grinding, and they are plain that you do not run the tool without one. HSG17 treats the guard and the mounting as part of the job. Point the closed side so sparks and fragments go away from your hands, your face and anything that will burn. A loose guard is not a minor rattle. A DEWINNER review in this set describes a guard that would not hold and a near miss. If the guard will not lock, you do not start. Both hands stay on the tool once the battery goes back on. A grinder that snatches will twist harder than a drill. Do not take the guard off to squeeze on a larger wheel. If the disc and the guard are a different size, you have the wrong pair.
Ryobi Ryobi R18AG-0 115 mm bare

Testsieger

Ryobi Ryobi R18AG-0 115 mm bare
9.4/10about £66.65
View offer

A short cut, then stop

Clamp the work. Electrical Safety First puts the clamp ahead of the spark, because a bracket that walks will catch the disc. Bring the wheel up to speed, then use light pressure and let the abrasive cut. Forcing the tool is how a thin disc grabs. When the cut is through, lift clear, let the disc stop, then take the battery off before you inspect the edge. A wheel that vibrates, smells of burning, or has glazed means you stop. No listing in this comparison states a vibration figure, so do not invent one for a named body.

Eyes, ears, and work versus home

Wear eye protection meant for grinding, gloves you can still grip with, and hearing protection once the disc is on steel. At home, these sources do not describe a domestic certificate. The Control of Vibration at Work Regulations 2005 set an action value of 2.5 m/s² A(8) and a limit of 5 m/s² A(8). No listing here states a vibration figure, so you cannot calculate a personal exposure from the bullets. The HSE's rule of thumb is about one hour on non-hammer tools toward the action value. That is their rule of thumb, not a measured shift on a named body. If you are mounting wheels for other people without that training, stop. This page is from the Products Compared editorial team, updated on 15 October 2026, from UK safety sources and these listings, with no lab test. A qualifying purchase through our links can earn a commission at no extra cost to you.

Common questions

What should I wear?
Wear grinding eye protection and gloves, and add hearing protection once the disc meets metal. Electrical Safety First names eyes, gloves and sparks, and it is written mainly for corded grinders, so you still remove the battery yourself. At work, the employer supplies eye protection when the risk assessment requires it.
Do I need training if this is only at home?
The sources used here do not describe a domestic certificate for a shed or a driveway. You still take the battery off, match the wheel speed, keep the guard on and clamp the work. If you are unsure of the disc, or the guard will not lock, do not teach yourself by starting the tool.
What if I use it at work?
At work the grinder is work equipment. PUWER absorbed the older abrasive-wheel appointment rules, and HSG17 still expects practical training and a record. Your employer provides eye protection when the assessment says so. You do not mount wheels for colleagues if you have not been trained to do it. Home practice on your own bracket is not that training.
Can I grind with a cutting disc?
No. A cutting disc stays in the cut. Grinding on its face, or twisting it to deburr, is how a thin wheel breaks. Flap discs and grinding wheels are for finishing, and they need the guard position for that job. If you only have a cutting disc, finish the edge another way.
Why did the battery die in twenty minutes?
A continuous cut is a heavy load, and a single pack can be flat before the piece is finished. A second pack belongs in the setup, and you should not start a long cut on the last of the charge. Manuals that promise a much longer run are not what you plan around. Stop, swap or recharge, and do not lean harder on a dying tool still in the kerf.

Related pages

Sanders

Cordless angle grinder

115mm or 125mm angle grinder: which disc and guard

Best cordless angle grinder UK for XR packs or a kit

Cordless angle grinder buying guide for kit or body

Cutting metal with a cordless angle grinder safely

Sources

Public UK sources named for workplace guards, abrasive wheels, vibration, and the grinder standard. amazon.co.uk prices, stars, and review counts are the figures stored for these twelve listings. Prices move.

  1. HSE, PUWER overview (retrieved October 2026)
  2. HSE, HSG17, Safety in the use of abrasive wheels (retrieved October 2026)
  3. HSE, INDG175, hand-arm vibration (retrieved October 2026)
  4. Control of Vibration at Work Regulations 2005, regulation 4 (retrieved October 2026)
  5. IEC 62841-2-3:2020, particular requirements for hand-held grinders (retrieved October 2026)
  6. OSA, EN 12413 marking note for bonded abrasives (retrieved October 2026)
  7. Electrical Safety First, angle grinders (retrieved October 2026)