This part of EN 10294 specifies the technical delivery conditions for seamless steel hollow bars intended for the manufacture of engineering components by machining. Machinability requirements are defined and a list of hollow bar size codes is given with the related dimensions achievable after machining when centring on the outside diameter. NOTE Dimensional requirements for other products, for example, applying when centring on the inside diameter may be agreed between purchaser and manufacturer at the time of enquiry and order (see Options 3 and 4).