New oscillating multitool blades can be expensive, so it’s worth sharpening the old ones.

There are several online videos showing different methods, ranging from hand filing to power grinding.

If the teeth are still partially there, use them as a guide and recut them with a small file.

A traditional triangular saw-sharpening file works, but I’ve found a cheap, diamond-coated one is even better.

You don’t have to be too precise, because once recut, any oscillating blade with a serrated edge seems to work well.

However, a powered mini grinder makes the job much quicker, especially if the teeth are worn away.

Some people even advocate grinding off any old worn teeth and starting from scratch.

The finished recut teeth on the multitool blade. Credit: Dick Everitt

Just clamp the blade between two bits of wood in a vice and recut the teeth.

When I first tried doing it freehand, I made a mess because it was hard to hold the grinder steady enough to cut the teeth evenly.

The answer is to clamp another piece of wood alongside the vice, to rest the grinder on.

Then, just rock the tool up and down and work along the blade.

Cutting straight across the blade seems to work, so there’s no need to cut teeth at a precise angle.

Even my really dodgy recut teeth seem to work fine on wood and fibreglass.

As always, remember the safety rules and protect yourself from the possibility of cheap, thin grinding wheels breaking up!

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