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How to use a Worx angle grinder

Updated: October 2026

A Worx angle grinder snatches when the disc is wrong, the guard is off, or you hold the tool with one hand while the work moves. This guide is for fitting a disc at home on a 20 V Worx or on the corded WX717, and for knowing when to stop. The steps use listing contents, Worx manual wording for related models, and HSE and Electrical Safety First guidance. This is not a lab test. A qualifying purchase through our links can earn a commission at no extra cost to you. Model choice sits on the [Worx angle grinder comparison](/hub/sanders/worx-angle-grinder). Mains or battery is the [cordless and corded comparison](/hub/sanders/worx-angle-grinder/sub/worx-angle-grinder-cordless-vs-corded).

A Worx angle grinder snatches when the disc is wrong, the guard is off, or you hold the tool with one hand while the work moves.

Our top picks

Worx Worx WX812 125 mm kit

Best overall

Worx Worx WX812 125 mm kit
9.2/10about £144.49
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Worx Worx WX803.9 125 mm bare

Best value

Worx Worx WX803.9 125 mm bare
9.0/10about £81.41
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Worx Worx WX717 750 W corded 115 mm

Rank 3

Worx Worx WX717 750 W corded 115 mm
8.0/10about £60.36
View offer
On this page
  1. 1.Before you touch the disc
  2. 2.Fit the disc and set the guard
  3. 3.Run it, then cut
  4. 4.Pick the right disc for the job
  5. 5.When to stop and ask a competent person

Before you touch the disc

Take the battery off a cordless Worx, or unplug the WX717, before the spanner goes near the flange. Electrical Safety First says isolate the tool, then change the disc. A 20 V pack can still spin the tool if the switch is bumped. The guard stays between you and the disc. HSE’s HSG17 records serious accidents when a guard is removed so an oversize wheel will fit. The disc’s marked maximum rpm must be at least the tool’s no-load speed: 8,500 rpm on the WX812, 8,600 on the WX803.9, 11,000 on the WX717 and 19,000 on the WX801.9. A disc below that speed, or of the wrong diameter, does not go on. These listings give no vibration figure.

Fit the disc and set the guard

Hold the spindle lock only when the spindle has stopped. Your own manual counts if the pictures differ from the WX701.1 and WX707.1 booklets. Seat the inner flange, the disc, the outer flange and the nut. On those manuals the raised side faces the disc for grinding and faces away for cutting. Do not overtighten. Farmers Weekly lists that among the ways discs get damaged. The guard has to lock between you and the wheel. The WX717 listing names tool-free adjustment. If the guard will not lock, stop. Do not start the motor until the key is out of the nut.
Worx Worx WX812 125 mm kit

Testsieger

Worx Worx WX812 125 mm kit
9.2/10about £144.49
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Run it, then cut

Run the new disc with nobody in line with the wheel. HSE asks for a short full-speed run after a wheel is fitted. Electrical Safety First says at least 30 seconds. Stand to the side. If you hear a knock, isolate the tool and refit the disc. Clamp the work, or a loose piece will climb the disc. Use both hands, bring the disc to speed before it touches the metal, and use light pressure. Keep solvent rags away from the sparks. Let the disc stop before you set the tool down.

Pick the right disc for the job

A grinding disc is not a cutting disc. A roughing disc meets the metal at a shallow angle. A cutting disc enters the cut square. A disc past its marked life does not get one last cut. The WX803.9 box includes a metal roughing disc. The WX717 and the WX812 include a metal grinding disc. None of those three is a cutting disc. The WX801.9 box is the exception, with 76 mm cutting discs and a diamond disc for masonry, not steel. To cut a bolt on the WX803.9, fit a 125 mm cutting disc marked for at least 8,600 rpm.

When to stop and ask a competent person

Stop if the cut is structural, if the guard will not lock, if the tool has snatched, or if the disc is cracked or missing its label. Stop if you suspect asbestos, lead paint or heavy dust in an enclosed room. At work, PUWER 1998 requires a suitable guard and training. HSE’s HSG17 is the guide dutyholders use. This page is not that training. Anti-kickback on the WX812 is a cut-out when a jam is detected. Reviewers say it works. It is not a promise that a snatch cannot injure you. Disc size is the buying guide. Pack runtime is the PowerShare battery page.

Common questions

How do I change the disc on a Worx angle grinder?
Remove the battery or unplug the tool. Wait until the spindle has stopped, press the spindle lock, and undo the flange. Fit the inner flange, the correct disc and the outer flange, tighten without crushing the disc, and take the key out. Check your own manual if the flange picture differs.
Which way round does the flange go?
On the Worx manuals for the WX701.1 and WX707.1, the raised side of the flange faces the disc for grinding and faces away for cutting. Those booklets are not the WX812 or the WX717 manual. Read the diagram for your model. If you cannot tell which way the flange sits, do not start the tool.
Can I cut metal with the grinding disc that came in the box?
No. The WX717 and WX812 boxes list a metal grinding disc, and the WX803.9 lists a metal roughing disc. Those remove metal by grinding. Cutting needs a cutting disc of the same diameter, with a maximum rpm at least as high as the tool. The WX801.9 box does include 76 mm cutting discs. A diamond disc in that box is for masonry, not for steel.
What PPE do I need?
Electrical Safety First names goggles and gloves, and you need both hands on the tool. Add a suitable dust mask when the material will throw fine dust, and keep skin covered against sparks. Hearing protection is sensible for a long cut, but these listings publish no decibel figure, so none is invented here. PPE does not replace a guard or a clamped workpiece.
How long do I run a new disc before cutting?
Run it up with everyone clear of the wheel line. Electrical Safety First says at least 30 seconds. HSE’s abrasive-wheels guidance asks for a short full-speed run after a wheel is fitted, with people standing clear. If you hear a knock or see a wobble, isolate the tool and refit the disc. Do not start the cut during that run.

Related pages

Sanders

Worx angle grinder

Best Worx angle grinder with or without a 20 V pack

Worx angle grinder buying guide for disc and battery

Cordless vs corded Worx angle grinder beside a socket

Worx angle grinder battery for a 2.0 or 4.0 Ah pack

Sources

Worx UK and Worx Europe pages for the range, PowerShare and warranty, plus HSE guidance on abrasive wheels and vibration, and the UK plugs regulations. Listing prices and star counts are from the amazon.co.uk extracts kept for this comparison on 16 October 2026. Prices move.

  1. Worx UK, Angle grinders (retrieved 16 October 2026)
  2. Worx Europe, WX803.9 (retrieved 16 October 2026)
  3. Worx UK, PowerShare (retrieved 16 October 2026)
  4. Worx UK, Product warranty (retrieved 16 October 2026)
  5. HSE, HSG17 Safety in the use of abrasive wheels (retrieved 16 October 2026)
  6. HSE, INDG175 Hand-arm vibration (retrieved 16 October 2026)
  7. HSE, Vibration risk assessment (retrieved 16 October 2026)
  8. Plugs and Sockets etc. (Safety) Regulations 1994 (retrieved 16 October 2026)