Laydown Threading Catalogue Numbering System Laydown Threading Toolholder Identification System AL253R A L 25 3 R Toolholder Tool Type Shank Size Insert Hand of Construction Size Tool A— Toolholders RH — Shim required Thread symbol R • First two numbers are shank height N— in mm. LH — Without shim Thread symbol L L — External Thread d L1 symbol d L1 2 6,35 11 3 9,52 16 4 12,7 22 5 15,88 27 widia.com F69