1. Straight-axis shafts

1. with uniform cross-section along their length
2. with variable cross-section along their length

2. Shaped shafts (such as crankshafts)

• solid shafts
• hollow shafts

• circular shafts
• non-circular shafts

1. shaft subjected to bending: stationary shaft with rotating discs
2. shaft subjected to torsion: shaft rotating together with the disc
3. shaft subjected to combined bending and torsion: shaft rotating together with the discs

Shafts can also be categorised by the materials they are made from. Typical shaft materials include:

• steel, structural steel (grades from S275 and those with designation 'E')
• alloy steels such as chromium-molybdenum (CrMo) and chromium-manganese (CrMn) steels
• case-hardened steels
• cast iron
• composite materials
• cermets (metal-ceramic), sintered materials
• plastics