northeast, northwest; southeast, southwest never hyphenated
ridgepole; tiestring, bowstring, drawstring
woodenware, smoothbore, midleg, handboard
pipestem, sealthong, centerbit
whale-fish, whale-skin, whale-iron, whale-harpoon
but whalebone, whaleman/whalemen
breechloader but muzzle-loader, -loading
foreshaft and fore-shaft, treenail and tree-nail
Words in -skin are generally hyphenated, but exceptions are not marked. The forms “needlecase” (one word, no hyphen) and “needle case” (two words) both occur.