Etterstramming

Etterstramming is the process of tightening a fastener or joint again after it has loosened since the initial installation. The term is used in Norwegian and is applicable in engineering, construction, and maintenance contexts. The goal is to restore the intended preload and ensure the integrity, safety, and performance of the connection.

Loosening can occur due to vibration, thermal cycling, material creep, settling, or improper initial torque. It is commonly applied to bolted connections, threaded fasteners, flange joints, and structural or mechanical assemblies, as well as in automotive, industrial, and furniture contexts.

The procedure usually involves inspecting the connection for looseness, corrosion, or damage, and applying a controlled re-torque using the appropriate tool and torque specification from manufacturers or standards. In multi-bolt joints, retightening is typically performed in a defined sequence to evenly distribute load. Some connections use locking devices such as thread lockers, locking washers, or prevailing-torque fasteners to reduce subsequent loosening.

Best practices include avoiding over-tightening, which can strip threads or damage components; ensuring proper thread engagement and cleanliness; and accounting for temperature effects or lubrication that can alter torque readings. If a fastener shows signs of damage, corrosion, or excessive movement, replacement is advised rather than re-tightening.

In English, the term is sometimes rendered as re-tightening or retorquing. Retightening intervals depend on service conditions, vibration, load demands, and industry standards.