How do I tell what chain I have / need?
It is important to note that when we describe any length in the world of chainsaws it is the approximate CUTTING length of the guide bar!
It is NOT the overall length of the guide bar or chain!
The first thing we recommend you do is work out how long your chain is. Chains are measured by the number of drive links (this is because chains stretch during their lifetime). The diagram below shows the drive link, it is the tooth on the inside of the chain loop, it sits inside the groove of the guide bar. The easiest way to count them is to take the chain off the saw.
Sometimes these drive links may have a code stamped into them, e.g 91, N1 etc, this will vary by chain manufacturer but it will identify the chain type for you.
If this marking does not exist then we need to next work out the pitch of the chain. The pitch is the distance between three of the chain 'rivets' divided by two. Common measurements are 3/8" or 0.325". (Chains are still measured in imperial measurements, but a few manufacturers are starting to publish data in both imperial and metric measurements).
Finally we need to know the gauge of the Drive Link. This will need to be done with the help of a micrometer or vernier calipers. The measurement will only be approximate as on an old chain there will be a lot of wear, hence a new chain may measure 0.050" (1.3mm) a worn chain may be only 1.25mm. Common chain gauges are :
0.043" (1.1mm), 0.050" (1.3mm), 0.058" (1.5mm), 0.063" (1.6mm)
Hopefully you will find a marking on the Drive Link, most quality chains have them in one form or another. Please click here to enter the Chain Identification Chart.