Is it acceptable practice to alter a bolt’s length in the field if it is too long?

Altering a bolt’s length or configuration in the field is acceptable as long as it does not change the length originally specified by the designer or engineer. If a bolt is longer than what was originally needed, the bolt can be cut down in the field. How the bolt is cut is important to consider. One common, acceptable method to cut down a fastener in the field is to use a type of saw. Another method used to cut steel in the field is a flame torch. Before doing this, it is important to make sure that the material being cut is not a heat treated material. In other words, if the bolt grade gets its strength through a heat treating process and heat is introduced to it in an uncontrolled environment (such as flame cutting), the mechanical properties can potentially be altered, which may compromise the strength of the fastener.

Certain grades of fasteners, such as A325 and A490 structural bolts have specific thread lengths associated with them, so altering the length may not be an option. There are also certain grades of anchor bolts that require a permanent grade and manufacturer’s stamp. If this end of the anchor bolt was to be cut down, the stamp would no longer be present; therefore the requirements of that particular specification would not be met.

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