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How to use a Ryobi angle grinder

Updated: 22 October 2026

The body is on the bench, the disc is still in the packet, and the battery from your drill is the only thing that will make it turn. How to use a Ryobi angle grinder, on these bare ONE+ tools, starts before the first spark: the pack comes off, the guard goes on, and the disc matches the tool. This page is the sequence for a first cut at home. The three listings are on the [Ryobi angle grinder comparison](/hub/tools/ryobi-angle-grinder). Follow the manual in your box for the latch and the nut. If you buy through our links, we may earn a commission at no extra cost to you.

The body is on the bench, the disc is still in the packet, and the battery from your drill is the only thing that will make it turn.

Our top picks

Ryobi Ryobi R18AG-0

Best overall

Ryobi Ryobi R18AG-0
9.4/10about £66.65
View offer
Ryobi Ryobi RAG18BL-0

Alternative

Ryobi Ryobi RAG18BL-0
9.4/10about £149.95
View offer
Ryobi Ryobi PBLAG02B

Rank 3

Ryobi Ryobi PBLAG02B
8.8/10about £87.71
View offer
On this page
  1. 1.Before the disc comes off
  2. 2.Guard and disc
  3. 3.What the switch will and will not do
  4. 4.When to stop

Before the disc comes off

These grinders have no mains lead, so pulling a plug is the wrong picture. Electrical Safety First tells you to isolate an angle grinder before a wheel change. On a cordless ONE+ body the battery comes off and stays off until the guard and the disc are seated. A charger, if you own one, needs a UK 3-pin plug and fuse. Clamp the work. A bolt you are still holding is how a disc grabs, and keep sparks away from you and from fuel. Take the pack off even to look at the nut. One UK review on the R18AG-0 says the disc would not unlock and the spanner snapped. The RAG18BL listing names a tool-less guard and nut. The R18AG listing names a tool-less wheel guard. Do not copy an American wrench sequence onto a tool-less nut.

Guard and disc

The guard stays on, between you and the disc, with the open side towards the work. If it will not seat, you stop. The R18AG-0 highlight is 115 mm at 7,500 rpm. The RAG18BL-0 is 125 mm at 9,200 rpm. A 125 mm disc on the 115 mm guard is the wrong disc. The disc's speed rating has to be at least the tool's no-load speed. A wheel marked below 7,500 rpm does not go on the R18AG-0. A wheel marked below 9,200 rpm does not go on the RAG18BL-0. PSA5, 14 March 2023, says to stop using toothed saw blades and chainsaw discs on angle grinders, and it cites BS EN 60745-2-3. A wood line on Ryobi's category FAQ does not overrule that alert. Disc class is on the Ryobi angle grinder buying guide.
Ryobi Ryobi R18AG-0

Testsieger

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

What the switch will and will not do

Ryobi's UK page for the R18AG-0 describes a two-stage switch that will not lock on. UK reviews find that awkward away from bench height. You hold the switch for the whole cut, and it stops when your hand comes off. The RAG18BL-0 listing names a paddle, and electronic anti-kickback that shuts the tool down when a jam is detected. Those lines do not transfer to the R18AG-0. The R18AG7 is a different code with a lock-on switch. Do not give that switch to the RAG18BL because both are called brushless. Let the disc reach speed before it touches the metal. Anti-kickback, where the listing states it, is a shutdown after a jam, not a reason to push harder. A long cut can fade a small pack. That limit is on the Ryobi angle grinder battery size page.

When to stop

Stop when the disc is cracked, glazed, or the wrong diameter, when the guard will not lock, or when you cannot clamp the work. Stop if the tool starts as soon as the battery is fitted, before you touch the trigger. That is one non-UK review on the PBLAG02B file, not a British rate. At work, HSG17 and PUWER 1998 expect training before you mount abrasive wheels. A dealer sheet for the RAG18125 quotes grinding vibration of 5.5 m/s². HSE's action value is 2.5 m/s² and the limit is 5.0. Noise action values sit at 80 and 85 dB(A). Fit the pack last, after the guard and the disc.

Common questions

Do I take the battery off to change the disc?
Yes. On these cordless bodies the isolation step is removing the ONE+ pack. Electrical Safety First puts isolation before a wheel change. Leave the pack off until the guard is seated and the disc is tight. The charger is the part that uses a UK plug, and only if you own one.
Where should the guard sit?
Between you and the disc, open side towards the work. If it will not latch, you do not cut. The exact turn is in the manual for your model. A tool-less guard on the listing is not an invitation to run the tool open, and a US spanner guide is not the sequence for a tool-less nut.
Can I cut wood with a saw blade?
No. PSA5, 14 March 2023, says to stop using toothed saw blades and chainsaw discs on angle grinders. A line on Ryobi's FAQ about wood depending on the disc does not cancel that alert. Use a disc the label allows, rated for at least the tool's stated rpm.
The disc will not come off. What is in the reviews?
One R18AG-0 review says the disc would not unlock and the spanner snapped. That is one report. Take the battery off, follow the manual, and stop if the nut will not move. Do not keep levering a tool-less nut because a video of a different grinder did.
When should I stop and get someone else?
Stop if the guard will not lock, the disc is damaged, or the tool runs as soon as the pack is on. Get a trained person for site work where PUWER applies, for 110 V cutting, and for structural or overhead jobs you cannot clamp. A household bolt you can clamp is the scale these bare bodies are being asked about.

Related pages

Brushed or brushless Ryobi angle grinder

Best Ryobi angle grinder

Ryobi angle grinder

Ryobi angle grinder battery size before a bare buy

Ryobi angle grinder buying guide for ONE+ pack owners

Sources

Public UK sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the three amazon.co.uk listings captured on 19 October 2026. Ryobi shop prices that week are not the comparison rows. HSE vibration limits and PUWER apply at work. They are not a certificate for a domestic cut. There is no laboratory test.

  1. Ryobi UK, R18AG-0 (retrieved 21 October 2026)
  2. Ryobi UK, R18AG-140S (retrieved 21 October 2026)
  3. Ryobi UK, angle grinders (retrieved 21 October 2026)
  4. Ryobi UK, RAG18125-0 (retrieved 21 October 2026)
  5. HSE, HSG17 Safety in the use of abrasive wheels (retrieved 21 October 2026)
  6. HSE, Hand-arm vibration regulations (retrieved 21 October 2026)
  7. OPSS, PSA5 toothed saw blade attachments (retrieved 21 October 2026)
  8. Electrical Safety First, Angle grinders (retrieved 21 October 2026)