30-40-50 comb shell end mill arbors Drawbar end thread: Inch30# 1/2"-13, 40# 5/8"-11, 50# 1"-8 Metric:30# M12, 40# M16, 50# M24 InchArbor Dia.30 Model No.40 Model No.50 Model No.1/2"210-3132 5/8"210-3140210-4140210-51403/4"210-3148210-4148210-51487/8"210-3156210-4156210-51561"210-3164210-4164210-51641-1/4"210-3166210-4166210-51661-1/2" 210-4168210-51682" 210-4170210-5170MetricArbor Dia.30 Model No.40 Model No.50 Model No.13mm210-3213 16mm210-3216210-4216210-521622mm210-3222210-4222210-522227mm210-3227210-4227210-522732mm210-3232210-4232210-523240mm 210-4240210-524050mm 210-4250210-5250