How to choose a chainsaw chain sharpener

1. Where will you actually be when the chain goes dull?

This is the question that decides everything else. A bench grinder is the most capable machine on the market and it is useless at the fourth property of the day. If your chain dulls away from a workshop, you need a tool that clamps to the bar and works in place.

2. Guided or free-hand?

Free-hand filing is cheap and skilled. A guide — whether a file holder or a bar-mounted clamp — fixes the top plate angle mechanically, which is what produces cutters of equal length and angle around the whole chain. If your cuts curve, you have a consistency problem, and a guide is the fix.

3. What chain pitch (or pitches) do you run?

Some excellent tools are locked to one pitch. If you own several saws, check compatibility before you buy, or choose a guided bar-mounted tool that covers a range of bar lengths in one unit.

4. Does it handle the depth gauges?

Every sharpening shortens the cutters, so the rakers in front of them effectively grow. A tool or kit that ignores depth gauges will eventually leave you with a razor-sharp chain that will not cut. Either the tool addresses them, or you need a separate depth gauge tool and the discipline to use it.

5. What is the running cost?

Files wear out. Burrs wear out. Grinding wheels wear out. All three are cheap; just make sure replacements are actually available for the tool you buy — a proprietary consumable with no supply is a dead tool.

What to ignore

• Claims of "professional grade" with no specification behind them
• Sharpening-time claims measured on a brand-new chain
• Review counts without a verifiable source
• Any price or discount you cannot check on the seller's own page