How to change a mitre saw blade

Choosing the right blade

Check three numbers in your manual or on the saw: blade diameter, bore and maximum speed. Common UK sizes are 210 mm, 216 mm, 254 mm and 305 mm, with bores of 30 mm or 25.4 mm. The blade's maximum speed must be at least the saw's no load speed. Kerf thickness should suit the saw's riving knife, if fitted.

Tooth count sets the finish: around 40 to 48 teeth for general cuts, 60 to 80 for fine trim. See mitre and circular saw blades explained and what size mitre saw do you need.

Getting ready

Unplug the saw or remove the battery. This is the most important step. Lower and lock the head if your saw has a transport pin, or keep it raised as the manual says. Wear gloves when handling blades; the teeth are sharp.

Note:Never change a blade with the saw connected to power. Check the guard returns freely before using the saw again.

Step by step

These steps fit most mitre saws. Your manual may differ in the order of guard and cover removal, so follow it where it does.

1. 1

   Raise the lower guard and, if needed, undo the screw holding the guard bracket or arbor cover.

2. 2

   Press and hold the spindle lock, then turn the blade slowly until it locks.

3. 3

   Undo the arbor bolt with the key. Many mitre saws use a left hand thread, so turn clockwise to loosen; check your manual.

4. 4

   Remove the bolt, outer flange and the old blade. Clean resin and dust off the flanges.

5. 5

   Fit the new blade with the arrow matching the direction on the guard, teeth pointing down at the front.

6. 6

   Refit the outer flange and bolt, hold the spindle lock and tighten firmly, without excess force.

7. 7

   Refit any cover or bracket, check the guard moves freely and spin the blade by hand.

See mitre saws →

After fitting

Reconnect power, stand to the side and run the saw for a few seconds to listen for rubbing or wobble. Make a test cut in scrap and check it with a square. A new blade can reveal that the saw needs calibrating; see mitre saw not cutting square.

If the saw has a laser or shadow line, check it still lines up with the cut after the change.

Looking after blades

Resin build up makes blades cut slower and burn the wood. Clean blades with a blade cleaner or warm soapy water and a soft brush, then dry them. Store spare blades in their cases so the teeth are not knocked.

Dull TCT blades can often be resharpened by a saw doctor. See how long do circular saw blades last for when that makes sense.

Common problems

If the bolt will not move, make sure you are turning it the right way; with a left hand thread it feels backwards. A sharp tap on the key while holding the spindle lock usually frees it. Never use a pipe extension on the key, which can break the lock.

If the new blade wobbles, check the flanges are clean and seated, and that the bore matches without a loose reducing ring.

Frequently asked questions

Which way do you undo a mitre saw blade bolt? On many saws it is a left hand thread, so clockwise loosens. Check the arrow on the saw or your manual.

Can I fit a 254 mm blade on a 216 mm saw? No. Use only the diameter the saw specifies.

Which way should the teeth face? Teeth point down at the front, matching the arrow on the guard.

How often should I change the blade? When cuts burn, splinter or need more force. Cleaning may help first.