Any question answered...

Ooh, lovely. I have a Park one - the one with the little plastic wheely thing at the bottom which I still don't know the purpose of.

It is for installing the arm cap on shimano cranks, they don't require a great deal of force.

http://fcdn.mtbr.com/attachments/drivetrain-shifters-derailleurs-cranks/797866d1368188384-torx-bit-size-slx-crank-cranknut.jpg

I'm not sure if I did the arm-cap up too tightly, or left it there too long, but the plastic spinner on the Park tool is useless for removing it, The allen key holding the spinner undoes, rather than the arm-cap.