This part of ISO 6507 specifies a method of verification of testing machines for determiningVickers hardness in accordance with ISO 6507-1.It describes a direct verification method for checking the main functions of the machine, and anindirect verification method suitable for the overall checking of the machine. The indirectverification method may be used on its own for periodic routine checking of the machine inservice.If a testing machine is also to be used for other methods of hardness testing, it is essential thatit is verified independently for each method.Portable hardness testing machines shall comply with all the requirements of this part ofISO 6507, but the word "relocation" in 6.1a) does not apply. The force values in this part of ISO 6507 were calculated from kilogram force values. They wereintroduced before the SI-system was adopted. It was decided to keep the values based on the old units for this edition, but for the next revision it will be necessary to consider the advantage of introducing rounded values of test force and the consequence on the hardness scales.