Installing a chain on an electric chainsaw can seem like a monumentally frustrating task. With a little practice, however, changing out a new chain can take only a matter of minutes. So whether your old chain is broken, thrown from the saw's bar or just needs replacing, you can put the chain back on the saw yourself with some guidance.
Turn off and unplug the chainsaw. Unlock the hand brake by pulling back on the brake's handle. The hand brake runs across the topside of the body and is in between the throttle and the bar. Spin the chain with your gloved hand to make sure the hand brake is off.
Unscrew the bar's faceplate screws or bolts, whichever your model has, with the screwdriver or wrench. The faceplate is located opposite of the muffler, and, if looking at the bar, is usually located on the right-hand side. Remove the faceplate cover.
Loosen the bar's tensioner screw with the screwdriver. The bar's tensioner screw can be located in a number of different places. On some models it will be a small flathead screw in between the two metal posts that the faceplate attaches to. On other models it may not be a screw, but a knob or dial that you must turn by hand. In most chainsaws, you must turn the screw or knob counterclockwise until the bar and chain are loose enough to slide off the sprocket. The sprocket is the notched wheel that sits at the base of the bar.
Take off the bar and, if the old chain is still attached, remove it from the bar. With your thumb and forefinger, hold up the new chain in front of you. Make sure the teeth's sharp points are facing up. If they're facing down, the chain will be on backwards and will not cut.
With your other hand, hold the bar so the tip is facing up. Slide the bar's tip into the top of the chain where your thumb and forefinger are holding the chain. Thread the chain's runners around the tip of the bar. When the chain is in place over the tip, grab and pinch the very tip of the bar and chain with your thumb and forefinger. Let the chain hang loose on the bar.
Grab the bottom of the chain, and pull it tight. Thread the chain's runners over the guide slot on one side of the bar. Once one side is in place, slide the chain's other side in place. Pull the bottom of the chain tight again.
Set the bar and chain back onto the saw. Put the chain's bottom end over the sprocket. Lay the bar and chain down over the tensioner rod and faceplate rods. Hold the bar and chain in place with one hand while you tighten the bar's tensioner screw or knob with the other. Tighten until the chain is tight around the bar.
Put the faceplate cover back on by attaching it over the bar and chain. Screw the screws back in place with the screwdriver until they are tight. With your gloved hand, spin the chain around the bar. The chain should slide over the bar with ease.
Depending on the project, you may want a tighter or looser chain. For cutting brush and shrubs, a tighter chain is preferred to keep the chain from getting pinched or thrown from the bar. For cutting logs or trees, a looser chain is preferred to keep the chain cutting through the thicker wood. Always wear the proper personal protective equipment when using chain saws.
Do not over tighten the chain. Over-tightening may cause the chain to break and fly back into your legs.