7 mm thin-wall tube spanner or hex socket

[Grant Bowker]

Originally Posted by Mike Kelly

Wear face protection and rotate the socket slowly. The socket will want to fly off so it needs to be firmly jammed onto the extension.

I agree that safety should be a factor in this operation. Consider the relative motion of the part being turned down (socket) and the "cutting tool" (file, grinding wheel, flap disk...) and try to arrange it so that the forces push the socket onto your holder (extension rod, mandrel, ...) rather than trying to make it fly to the far corner of your shop (through you).
I also agree that it would make so much sense if manufacturers would design assemblies to make service easy rather than hard, particularly if they are selling the repair/replacement parts (rather than leaving it to the aftermarket). Perhaps designers should have a mandatory month working (hands on, not observing) in repair shops each year to keep this in their minds...