Older machine designs can be given new life by retrofitting new motion control systems. Such is the case for Sunnen Products Co., St. Louis, and its latest generation of heavy-duty tube honing system, the HTG. Honing is done on the inner walls of oil drilling pipe, hydraulic cylinders, nuclear fuel rods, and other pipe segments to achieve a precision size while reducing metallurgical stress and creating a cross-hatched surface finish.
The HTG machine can hone tubes from 2 to 24 in. inside diameter (ID) in 2-m increments up to 14 m (46 ft) long. Although the original design performed well, the Sunnen team decided to make some control upgrades to enable higher material removal rates and improve operating stability.