The flanged side is to center the wheel, and should face the disk. You will
notice there's a lot of clearance between the shaft & the disk - the job of
the flange is to get it centred before it's tightened.

"Toller" wrote in message
...
I have never used anything but grinding (what, blades, inserts, disks?) in
my Makita 4.5" angle grinder, but today I need a cutting disk. It is
much thinner, so it just spins. The retaining nut is flat on one side and
flanged on the other. If I turn it around so the flat side is down, rather
than the flanged side down, it seems to work okay.
But I don't have the instructions, so I don't know if this is actually
proper.
Any catastrophe happen if I use it like this? If so, how do I mount the
cutting disk?