The maintenance of large diameter threads can be quite complicated and rather costly. Due to their larger size and weight, it is often difficult to work on the damaged threads at a workbench or on a table. The repairs have to be conducted on the spot. Furthermore, the larger diameters result in larger tools which require larger clearance to complete the repair. Traditionally, one would dismantle the entire part, bring it to the workshop and rethread it there. Oftentimes this may not be feasible to do by hand, subsequently requiring expensive power tools. Alternatively, one could use a thread file and quite a bit of elbow grease. Both of these methods are aggravatingly arduous and time-consuming.
The Nes3 external thread repair tool will slide into the thread and adjust to its diameter and pitch automatically. This tool can also be used on both left- and right-hand threads, inch and metric threads, and coarse and fine threads. It is able to repair a component that is damaged at the end of the thread, and its external thread restores have the capability to enter below the damaged area and work outwards to complete the repair.
Information provided by American Anglo Tools