Changing an angle grinder disc is quick and easy once you know how. Whether you’re swapping from a cutting disc to a flap disc, replacing a worn wheel, or fitting a diamond blade, the process is almost always the same.
This guide shows you three safe methods used on UK angle grinders:
- Using the spindle lock button
- Using the two‑pin grinder wrench
- Using tool‑free quick‑change nuts
A step‑by‑step visual guide is included below.
Step‑by‑Step Guide: How to Change an Angle Grinder Disc
Below is a clear, beginner‑friendly procedure using images (spindle lock, wrench tool, and grinder).
1 Disconnect Power
Safety First
Always isolate the grinder before touching the disc.
- Unplug corded grinders from the mains
- Remove the battery from cordless grinders
- Never change a disc while the tool is live
2 Press the Spindle Lock Button
This locks the spindle so the disc cannot rotate.
- Locate the spindle lock button on top of the grinder
- Press and hold it firmly
- Rotate the disc by hand until it clicks into a locked position
3. Loosen the Disc Using the Two‑Pin Wrench
Most grinders include a wrench that fits the locking flange.
- Insert the wrench pins into the holes on the flange nut
- Turn anti‑clockwise to loosen
- Remove the flange nut and lift off the old disc
4. Fit the New Disc
Place the new disc onto the spindle with the label facing outward.
- Ensure the disc sits flat on the backing flange
- Match the disc size to your grinder (115mm or 125mm)
- Check the rotation arrow on diamond blades
5. Tighten the Flange Nut
Secure the disc so it stays centred and stable.
- Thread the flange nut back on by hand
- Hold the spindle lock button again
- Tighten gently with the wrench — do not overtighten
6. Check the Disc Before Use
Final Check
A quick inspection prevents wobble, vibration, or disc failure.
- Spin the disc by hand to ensure it moves freely
- Make sure the guard is correctly positioned
- Reconnect power and let the disc reach full speed before cutting
Alternative Methods
1. Tool‑Free Quick‑Change Nuts
Some modern grinders use a quick‑release nut instead of a wrench.
How it works:
- Press the spindle lock
- Twist the nut by hand
- Swap the disc
- Tighten by hand
These are ideal if you change discs frequently.
2. Changing a Disc Without a Wrench (Emergency Only)
If you’ve lost the wrench:
- Press the spindle lock
- Grip the disc with a thick glove
- Turn anti‑clockwise to loosen
This works, but only use it if absolutely necessary.
Common Mistakes to Avoid
- ❌ Overtightening the flange nut
- ❌ Using the wrong disc size
- ❌ Forgetting to remove the battery
- ❌ Running the grinder with a loose disc
- ❌ Installing a disc backwards (check the label direction)
Which Disc Should You Fit?
- Cutting metal: thin 1–1.2mm cutting disc
- Grinding welds: thick grinding disc
- Smoothing metal: flap disc
- Cutting brick/slabs: diamond blade
- Removing rust: wire wheel