Which tool is recommended to shorten a capillary tube?

Using a triangular or knife-edge file is the most effective method for shortening a capillary tube due to the nature of the tubing material. Capillary tubes are typically made of thin, delicate materials that can be susceptible to deformation if cut improperly. A file allows for a controlled and precise approach, ensuring that the cut is smooth and clean without crushing or distorting the tube. By carefully filing down the tube, technicians can avoid creating burrs or sharp edges that could lead to leaks or improper functioning.

Other methods like wire cutters or a hacksaw can lead to jagged edges or deformation of the tube, making it difficult to properly connect or seal afterwards. A pipe wrench is not suitable for cutting at all and is designed for gripping and turning pipes rather than cutting. Therefore, the triangular or knife-edge file is specifically recommended because it provides the necessary precision and care required for working with capillary tubes.