A fastening method comprising using a control apparatus to select a first upsetting volume of an upsetting die (964), using a punch to push a first fastener into a workpiece and using the upsetting die (964) to upset the first fastener, then using the control apparatus to select a second upsetting volume of the upsetting die (964), using the punch to push a second fastener into a workpiece and using the upsetting die (964) to upset the second fastener. The first fastener and the second fastener have different dimensions and/or hardnesses.