G'day Paul,
Yes, the plates slide along their shaft.
I would make sure the shaft is clean and rust free by using a long strip of fine grade wet and dry sand paper, then lubricate it before using your rubber mallet.
Here is some information I have for the older type Cox mower. I've never seen the plates on a Stockman, cant imagine it being too much different.
The clearance from cone to plate is quite small.
![[Linked Image]](https://www.outdoorking-forum.com.au/forum/uploads/usergals/2014/01/full-4730-14860-clutch.jpg)
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