Joachim, I've dismantled it because I fitted the wheels to a larger grinder, I found the wheels were too close together on the small grinder and sharpening a longer blade was awkward. I now just use it freehand, works fine. I was overthinking it before!
Squid, it's not a problem because you don't apply heavy pressure for extended periods (unlike using grinding wheels or belt grinders). It isn't meant for hogging out steel, only for fine honing, sort of like a mechanical strop.