The soleplate is the iron casting to which the bedknife is mounted.
It's the biggest bit shown in this pic:
The thing is, it has to come out to dismount the bedknife, to permit use of the grooming reel. Then it has to go back in - it's an essential part of the chassis structure.
Last edited by Gadge; 20/08/1601:09 AM. Reason: Topic name change