I.Isingeniso Somkhiqizo:
Umkhiqizo uqukethe isisekelo sesampula kanye nezilinganiso eziyishumi zosayizi ezahlukene zepuleti eliphakathi, ezifanele ubukhulu besampula obungu-(0.1 ~ 0.58) mm, izincazelo eziyi-10 sezizonke, ezinamapuleti aphakathi ahlukene, angazivumelanisa nobukhulu besampula obuhlukene. Isetshenziswa kabanzi ekwenzeni amaphepha, ukupakisha kanye nokuqapha ikhwalithi yomkhiqizo kanye nezimboni kanye neminyango. Kuyithuluzi elikhethekile lokuhlola amandla okucindezela indandatho ephepha nekhadibhodi.
u No.1 0.100-0.140 mm
u No.2 0.141-0.170 mm
u No.3 0.171-0.200 mm
u No.4 0.201-0.230 mm
u No.5 0.231-0.280 mm
u No.6 0.281-0.320 mm
u No.7 0.321-0.370 mm
u No.8 0.371-0.420 mm
u No.9 0.421-0.500 mm
u No.10 0.501-0.580 mm