Threads are cut with the pipe die and a die stock, Figure 19-40. Dies are available for each pipe size. A smooth sleeve guides the die onto the pipe to ensure that it remains square with the end of the pipe, Figure 19-41. Cutting oil should be used to lubricate the die as threads are cut. Cutting, reaming, and threading can also be done using a powered pipe machine, Figure 19-42. Assembling and Supporting Galvanized and Black Iron Pipe Before assembling the pipe and fittings, apply pipe joint sealer or Teflon™ tape to the threads, Figure 19-43. This seals the joint and prevents leaks. The pipe or the fitting is turned clockwise with a pipe wrench to tighten the joint. See Figure 19-44. Galvanized and black iron pipe should be supported at 6′–8′ intervals using metal hangers. Installing Cast-Iron Pipe The correct allowances for the depth of the hub on common sizes of hub and spigot cast iron pipe are given in Figure 19-45. This allowance must be included when measuring pipe length. much like a tubing cutter —the tool is revolved around the pipe, with the cutter wheel tightened one-quarter to one-half turn with each revolution until the pipe is sheared. Once the cut is complete, a pipe reamer is used to remove the burr. See Figure 19-39. The Ridge Tool Co. Figure 19-38. A pipe cutter works in the same way as a tubing cutter. Goodheart-Willcox Publisher Figure 19-39. A reamer will remove the burr left from cutting of galvanized or black iron pipe. The Ridge Tool Co. Figure 19-40. A die and die stock are used when a pipe is threaded by hand. Die stock holds interchangeable dies. Sleeve guides pipe into die Pipe Incomplete threads Goodheart-Willcox Publisher Figure 19-41. Cutaway shows pipe being guided squarely into die. 318 Section 3 Plumbing System Design and Installation Copyright Goodheart-Willcox Co., Inc.