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Braking a grinder can speed up batch tool sharpening

If you sharpen turning tools with a grinder, you can set the adjustable platform to suit the grinding angle of the tool. But each kind of turning tool needs a different angle, so you may find you are continually re-setting the grinder platform. I have written about some simple jigs that make this accurate, repeatable and easy to do. But my grinder takes a long time to run down after switching off. I can’t use my setting jigs until the wheels have stopped. I wanted a way to stop the machine quickly to grind several different tools at the same time. But braking a grinder could either clog the wheels or cause unnecessary wear. There is a simple solution.

A rubber block of the kind sold for cleaning sanding belts pressed against the rim of the wheel will bring it to a stop very quickly. It leaves no significant residue on the wheel – if anything, the wheel is cleaner afterwards. The rubber gets worn away, but it will last a long time.

Risks when braking a grinder

There are two points to keep in mind. Braking a grinder too quickly could cause the wheels to loosen. Braking forces applied directly to a wheel will tend to tighten it, just as normal grinding does. But the inertia of the other wheel might make it over-run and loosen its retaining nut. This could allow the wheel to spin freely on the spindle and perhaps even come off. The wheel guards must stay in place, and the nut kept properly tight. I am confident that, if the wheel ever comes loose on my grinder (it hasn’t happened yet!), the guard will stop it coming off the spindle. If you don’t have that confidence, please allow your grinder to slow down in its own time.

The other risk is rubber particles accumulating in the wheel shroud. Grinding sparks could possibly ignite them. Again, this has never happened with my machine.

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