What is the point of these?

[Nozzle]

What is the point of these? They can't be used in a 115mm angle grinder as they spin too fast (normal speed ~11000rpm) and these are limited to 8500rpm.

https://www.toolstation.com/shop/Po...d1920/Abracs+Wire+Twist+Knot+Cup+Brush/p17385

To run these at the rated speed, they have to be fitted to a hulking great 230mm grinder (even some of these are too fast). And what then is the point of fitting a small cup brush to a massive grinder with associated large gearbox on the end..

It's fine with the twist-knot wheel kind, these are rated 11000rpm. Having fitted a cup brush to a 11000rpm grinder, I can confirm it's horrible.

Nozzle

 

[rsgaz]

angle grinder as they spin too fast

Don't polishers have an M14 thread too and spin at a much slower rpm?

edit: Here we go as an example, M14 thread and 3000rpm polisher.

 

[Nozzle]

Don't polishers have an M14 thread too and spin at a much slower rpm?

Not sure, my DA type has something like 5/16 UNF. Daft thing. Isn't 8500rpm too fast for a polisher? I've not looked at any specs

Nozzle

 

[foxhole]

Variable speed grinder.

 

[Roger928]

What is the point of these?

Fitting inside narrow spaces or channels.
For example cleaning 4" wide lengths of channel iron or rsj material. Should only be fitted to 230mm grinders imo.

 

[SammyInnit]

Variable speed grinder.

Beat me to it.

 

[TicTac]

I use one on a Dewalt XR18v 5" angle grinder, and that has a no load speed of 9000rpm; no problems with it. The 115s tend to run at 11,000, so you'd need a 125 to handle it

 

[muggles]

The point is that you buy the right attachment for the grinder you have. Screwfix 65mm twist cups are rated to 12500rpm