When jacking metal against metal, what is recommended to use?

When jacking metal against metal, using wood softeners is recommended to prevent damage to the surfaces being jacked. Wood softeners provide a cushioning effect that helps distribute the load more evenly across the surface. This not only minimizes the risk of scratching or marring the metal surfaces but also provides some level of friction to help secure the materials in place during the jacking process.

The choice of wood softeners recognizes the characteristics of metal surfaces that can be susceptible to deformation or damage under high load if no cushioning material is used. Wood has enough compressive strength to withstand the forces involved while still being soft enough to protect the underlying metal surfaces. Additionally, it is widely available and easy to work with in most rigging situations.

Other materials, while useful in different contexts, may not provide the same balance of support and protection needed when jacking metal against metal.