Chainsaw Repair

copy and pasted to go with pic below.

How to measure your chainsaw chain

How To Measure Your Chain

Here’s a quick little guide on how to measure up your chainsaw chain, and to see what you need to look for when buying a chain for your chainsaw (your bar size is also needed) -

1. Count the number of drive links on your chain

A drive link is the "tooth" on the bottom of your chainsaw chain that slots into the groove of the bar. The number of teeth, or drive links, equals the length of the chain.

Write down this number.

2. Find the pitch of your chain

The pitch is the distance in inches between any three rivets, divided by 2. The rivets are the "bolts" holding the links of your chain together.

The best way to find the pitch of your chain is in your product manual.
The most common pitches are 3/8" low profile, .325", 3/8" and .404"

It is possible to measure the pitch of a brand new chain however it is not adivsed to try and measure the pitch of a used chain. The difference between different pitches is very minute and when a chain is used it will cause stretching, distorting the measurement.

To calculate the pitch of your new chain you need to measure the distance from the centre of the first rivet to the centre of the third rivet.

Divide this length in half and write down this number.

**SEE DIAGRAM BELOW

3. Measure your chain's gauge in inches and write it down

The chain gauge is the width of the notch in the drive link where the link fits into the groove of the bar guide. This will be a very small number, around 0.050 or 0.063 of an inch for example, and must match the gauge of the guide bar.
The most common gauges for chainsaw chain are .043", .050", .058" and .063"
Try to find the gauge of your chain by looking in the saw's manual. If you have no luck with the manual then check to see if the gauge is displayed somewhere on your chainsaw bar.
If you have a brand new chain, you could try measuring the gauge using a micrometer.