Feather/knife (decr in reduction depth as finish line approached, conservative, no clear finish line, difficult to wax/cast), chamfer (decr in reduction depth as finish line approached, easy, conservative, limited space for PFM, cast 0.5mm, PFM 0.8-1mm), shoulder (flat margin perpendicular to occlusion, easy, thickness for PFM, resistance to distortion & occlusal forces, less conservative, cast, PFM or ceramic restoration), research (no significant differences between metal & porcelain shoulders before or after cementation, finish line forms dont affect fit of cemented crowns, default margin rounded shoulder - ease, impression, lab, marginal integrity)