Liners for hydraulic tongs and a spider are a replaceable part required to perform operations performed during capital or current workover of oil wells, as well as during drilling and development of wells. For safe and efficient operation, the liner of the hydraulic tong must be checked periodically and, if worn or damaged in any way, must be replaced.
Dies (crackers) for pipe wrenches and inserts (liners) for spiders are separate parts for this type of equipment. Designed for slip-free engagement of the tong jaws or spider wedges with the surface of drill, casing, tubing pipes. They have a raised working surface for stronger contact with the pipe surface. They are consumables and change as they wear out.