Large　SmCo5　single-crystal　spheres　are　used　as　simple　model　objects　for　both　theoretical　and　practical　studies　of　the　coercivity　mechanism　in　permanent　magnets　(PM).　These　samples　exhibit　coercivity　values　exceeding　1　T,　achieved　through　the　enhancement　of　surface　smoothness.　The　morphology　and　magnetic　results　indicate　that　surface　defects　play　a　key　role　in　the　reversal　mechanism　and　nucleation　process.　The　reversal　mechanism　and　coercivity　are　studied　by　means　of　different　magnetization　protocols,　shedding　light　on　the　influence　of　two　types　of　nucleus　of　reversal　magnetic　domains.　We　then　utilize　these　objects　to　probe　the　angular　dependence　of　coercivity.　Our　examination　of　samples　with　differing　surface　states　reveals　that　enhanced　surface　smoothness　corresponds　to　a　behavior　closer　to　the　coherent　rotation　model.　This　study　underscores　the　massive　influence　of　surface　defects　on　magnetization　reversal.　Thus,　the　reduction　of　imperfections　in　PM　grain　boundaries　holds　the　potential　to　significantly　increase　the　nucleation　field　and　thus　the　coercivity.　More　generally,　our　study　introduces　a　methodology　for　examining　the　magnetization　reversal　of　permanent　magnets　using　simple　model　objects.