How to identify chainsaw chain pitch, gauge and drive-link count

A compatible chain is not selected only by guide-bar length or chainsaw model. The three values that must match are pitch, drive-link gauge and drive-link count. Two chains may look almost identical, yet a single mismatch between these specifications can prevent correct fit or cause the cutting system to work improperly.

What chain pitch means

Pitch describes the spacing of the chain components and must match the chain, drive sprocket and, when the bar has a sprocket nose, the bar tip. Common values include 3/8, .325, .404 and 3/8 low profile. The 3/8 notation does not describe groove width and does not tell you the overall chain length.

If the marking is unreadable, pitch can be found by measuring the distance between the centres of three consecutive rivets and dividing the result by two. Wear can make measurements less reliable, so markings on the bar, original package or machine documentation are preferable whenever available.

How to check gauge

Gauge is the thickness of the drive link that runs inside the guide-bar groove. Catalogues commonly list 1.1 mm, 1.3 mm, 1.5 mm, 1.6 mm or 2.0 mm. It must match the groove: a drive link that is too thick will not enter, while one that is too thin will not be guided correctly.

Do not infer gauge from the cutter shape. Read the bar marking, identify the old chain code or measure a drive link with a suitable gauge. If the bar is badly worn, side-to-side play can make a visual estimate misleading and the bar itself should also be inspected.

Drive-link count determines actual length

The number you need is the count of drive links—the parts that run in the bar groove—not the count of cutters. This explains why bars with the same advertised length may require chains with different drive-link counts, depending on the mount and cutting-system geometry.

Place the chain on a clean surface and mark the first drive link. Count every drive link once until you return to the mark. If the original package or complete part number is available, use the printed count as an additional check rather than relying on memory.

A reliable checking order

Start with the markings on the bar currently fitted. Confirm the sprocket pitch, groove gauge and drive-link count. The chainsaw model is useful for narrowing the options, but some machines accept several cutting configurations. The assembly actually installed is more reliable than an assumption based on model alone.

Before fitting, compare the new chain with the old one and check cutter direction. Follow the machine manual for installation and tensioning. If markings conflict or remain unclear, do not force the chain into place; ask a qualified service shop or specialist supplier to confirm the configuration.

Pre-order checklist

• Chain pitch matches the sprocket and bar.
• Drive-link gauge matches the bar groove.
• The drive-link count is exact.
• The checked configuration is the one actually fitted to the machine.

To compare the available options, browse the chainsaw chain collection and use the specifications you have identified.