Bars and chains – a useful guide

1. How to ascertain the length of your bar

The best way to check the length of the bar is to read the markings off the bar itself, if possible. If this is too worn or dirty to read, you can work it out from measuring the bar – although, contrary to what you would expect, it is not the overall length from tip to toe of the bar! The nominal length is referred to as the ‘cutting length’, which is the part of the bar that protrudes from the chainsaw casing and is usually rounded up to the nearest inch.

2. Knowing the size of your chain

• The chain size is measured by the number of drive links on the chain. The drive links are the small ‘V’ shaped pieces that sit in the groove of the bar. Remove the chain from the saw and lay it on a flat surface. Mark one of the drive links, and starting here count the number of drive links working your way back to the starting link. You may be able to find the number of drive links printed on the side of the chainsaw bar, for example ‘56DL’ for 56 drive links.

The pitch

When buying a replacement chain its likely you’ll need to know the pitch. To do this you’ll need to know the distance between 3 consecutive rivets. Lay the chain on a flat surface so you can see the circular rivets. Start your tape measure on the edge of any rivet and measure to the edge of the third rivet, then divide the measurement by 2 to find the chain’s pitch. The pitch may also be listed in inches on the side of the chainsaw bar.

The gauge

The gauge refers to the thickness of the drive links that fit in the groove on the chainsaw bar. This is usually listed on the side of the chainsaw bar in inches, but if it’s worn off, you can find the gauge using a calliper. Place one of the drive links, (the ‘V’ shaped metal pieces on the inside of the chain), between the jaws of a calliper and slide the jaws closed, so it grips the drive link tightly. Check the measurement reading on the calliper to ascertain the gauge. The standard gauge sizes are 0.043 inches (1.1mm), 0.050 inches (1.3 mm), 0.058 inches (1.5 mm), and 0.063 inches (1.6 mm).

How to work out the correct file size for your chain