Angle grinder speed. And wire brushes.

[ericmark]

The discs advert says 10,000 RPM, but the disc says 4,500 RPM the max speed of grinder is 10,000 RPM, but it does have 6 speeds, but nothing in the paperwork says what speed it runs at when speed 1 is selected. So I am not sure about using the brushes, clearly using eye protection etc, but they do look as if designed to be used with a grinder, so has anyone had problems using these brushes with grinder speed set to lowest?

 

[jj4091]

The hole in the one illustrated does not look big enough to fit an angle grinder so I would suspect you would need an arbour and use with a drill.

 

[robinbanks]

You can get one of these for less than a tenner:

and satisfy your curiosity as to your grinder speeds. Your local friendly garage might have one the could lend you.

You might even be able to use you phone in slowmo video mode to record the grinder and count the revolutions (dot of tippex on a wheel) and extrapolate it out.. If the phone is recording at 240fps and over the course of 10 frames the wheel does 6 revolutions and the dot arrives back where it was it’s doing about 8600 rpm (6 revs per 1/24th of a second, times 24, times 60)

Perhaps another thing you could do is record the sound the grinder makes on high and low speeds and make an assessment of the audio frequency after loading it into a computer, which will allow you to judge the speed (ratio of frequency is ratio of speed: 2100hz at 10krpm, 700hz at low speed would be about 3300rpm )

Don’t forget, the wheel will be slowed some when it does work, so a no load speed that is a bit higher could be forgiven

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Or, forget the science, buy a wheel to sacrifice, weigh it then run it on low speed for 15 mins, weigh it again and see how much it’s lost