3a thread class right-hand crowned hexagon head style 28 thread quantity per inch ldistance from head largest bearing surface to shank hole center 2.090 in. min to 2.110 in. max; shank unthreaded hole diameter 0.078 in. min to 0.083 in. max; angle of domed head 88 degrees min to 92 degrees max unjf thread series
2a thread class right-hand headless (setscrew) head style 20 thread quantity per inch one hole in shank 0.136 in. dia passivate surface treated unc thread series
3a thread class right-hand headless (setscrew) head style 24 thread quantity per inch has two shoulders 0.151 in. dia; first shoulder 0.094 in. lg; second shoulder 0.057 in. lg; undercut 0.099 in. lg unf thread series
