The aluminum bolts may be used two times. Therefore, the bolts must be marked with an made by a chisel after they have been used the first time.
To prevent damaging the bolts when marking them, do not clamp them in a vise. Insert the bolt in a 14 mm socket with a 1 /2 drive, which is inserted in to the vise, as shown.
Bolts marked with an "X" may not be used again.