Does that bolt that won't come out move a bit then stop? It may be a captive cotter pin - if so you just loosen it and then it will allow the clutch-half to slide off the shaft.
Clutches often (usually in fact) have a plate that provides a friction surface to the two metal faces. This both increases friction and supplies an easily-replaced wearing surface. Cone clutches traditionally had a leather surface attached to one half of the clutch (that is, one of the matching cones), but this one may use cork instead to do the same job. It will be between the male and female cones, and it is supposed to wear out eventually.