https://youtu.be/wet0h9HA9VA
Nice! A clear view of the Tool Rest on the USB begins at about 0:31 sec.
(https://forum.tormek.com/index.php?action=dlattach;topic=3791.0;attach=2867)
It is not at all clear how it is mounted on the Tool Rest but it may be part of the parent machine. I think it would need to be fairly rigid and it appears that way to me. I don't see the blade wiggling with side pressure at all.
Nice logo for his sharpening business at the end also.
Rick
Why would one not use a diamond stone / file on the blade whilst still on the machine ?
Rich