Which tool is commonly used to expand copper tubing?

The swaging tool is specifically designed for expanding or enlarging the ends of copper tubing, allowing for a secure fit when connecting two pieces of tubing. This process is crucial in HVAC systems, where proper fittings and joints are essential for maintaining air tightness and system efficiency. The swaging process involves mechanically deforming the end of a copper tube, creating a wider opening that can then be joined with another tube or fitting without leaks.

As for the other tools, they serve different purposes in the realm of copper tubing. A copper bender is used for shaping copper tubing to fit around corners or curves, but it does not expand the tubing itself. A reamer is utilized to smooth and deburr the edges of cut tubing to prevent obstructions and ensure a tight seal with fittings, but it does not expand the diameter. A cutter tool is designed solely for cutting copper tubing to length, not for modifying its diameter. Thus, the swaging tool's specific function makes it the appropriate choice for expanding copper tubing.