During work, resin, sap and sawdust stick to the chain and guide bar. If they are not removed, the saw gradually cuts worse, the chain runs hot and the bar wears faster. Cutting pine and green timber clogs a saw especially quickly.
Chain and bar care is the same for petrol, corded and battery saws. No professional skills are needed, just care and protective clothing. If you are unsure, take the saw to a service centre.
What you will need
Important: The chain is very sharp: always wear heavy gloves. Stop a petrol saw and pull off the spark plug cap before servicing, unplug a corded saw and remove the battery from a cordless one.
Step 1
Secure the saw and remove the chain
Place the saw on a stable surface so it cannot slide. Loosen the chain with the tensioning screw, undo the sprocket cover nuts (usually two) and remove the cover.
Lift the chain off the bar and drive sprocket, then take off the bar. You will see everything is coated with sawdust and resin. Check your model's manual for specific details.
Step 2
Clean the chain, bar and housing
Over a tray that will catch the dirty run-off, spray WD-40 Multi-Use generously onto the chain, bar, sprocket and the area under the cover. It softens resin and hardened lubricant.
Scrub with a soft brush until the chain is clean. Clear the bar groove and the oil hole separately so lubricant can reach the chain. Finally wipe all parts with paper towel.
Step 3
Protect the metal from corrosion
Before reassembly, give the chain and bar another light coat of WD-40 Multi-Use and wipe with a dry cloth. The film displaces moisture and guards against rust, which matters most if the saw lives in a damp shed or works in rain and wet timber.
Step 4
Grease the bar sprocket and brake
Grease the nose sprocket through its dedicated hole until grease starts to appear. WD-40 Specialist White Lithium Grease suits the job: this thick lithium grease resists wash-out and stays on the metal. Turn the sprocket several times and wipe off the excess.
Check the chain brake: it must engage crisply. Treat its pivots with WD-40 Specialist Silicone, which is non-tacky and does not attract sawdust.
Step 5
Reassemble and set the tension
Fit the bar, place the chain over the sprocket and into the groove, refit the cover and nip the nuts lightly. Use the tensioning screw so that the chain does not sag but still turns easily by gloved hand.
Do not tighten the chain fully on a cold saw: the metal heats up and expands in use. Then tighten the nuts fully.
Step 6
Check the chain lubrication
Fill the tank with chain lubricant. Start the saw and hold the bar over a light-coloured surface: within a few seconds a line of spray should appear. If not, clean the oil channel again.
Tip: Flip the bar over at every service: the groove and rails then wear evenly and the bar lasts much longer.
What next
Do a quick clean after every working day and a full strip-down every 5-10 operating hours or after cutting resinous wood. For quick treatment in the field, WD-40 Smart Straw with its fine straw is very handy.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
More guides in «How to use».