Mild steelAKA: A36 / Q235 classCNC ᐱᔨᓴᕕᕋᔭᖅᐃᓚ ᐅᔭᕋEconomicalPowder / black oxideEasy to machineEconomical structural steel; powder / black oxide / zinc common.ᐃᓚ ᐃᓚᐊᑭᓕᕈᑎ
1045 ᐃᓚ ᓴᐅᔭAKA: 1045 / C45CNC ᐱᔨᐃᓚ ᐅᔭᕋMedium carbonShaftsHeat-treatableMedium-carbon steel; stronger than mild steel — common for shafts.ᐃᓚ ᐃᓚᐊᑭᓕᕈᑎ
4140 ᓴᕕᕋᔭᖅ ᓴᐅᔭAKA: 4140 / 42CrMo classCNC ᐱᔨᐃᓚ ᐅᔭᕋHigh strengthTough / impactConfirm heat treatAlloy structural steel; confirm heat treatment with engineering.ᐃᓚ ᐃᓚᐊᑭᓕᕈᑎ
ᐃᓚ ᓴᐅᔭ (ᐃᓚ)AKA: general tool-steel classCNC ᐱᔨᐃᓚ ᐅᔭᕋWear resistantTooling classSpecify grade in notesWear/tooling class — specify exact grade in notes (SKD / S136 etc. via engineer).ᐃᓚ ᐃᓚᐊᑭᓕᕈᑎ