no doubt threaded drill stems are the replacement of the old welded style drill stems. The higher strenght, better corrosion resistance, easier installation, handling and storage are some of the advantages over the old style. The longest reported and witnessed is in COP-Carson four drums were installed in 1982 aprox. and there is still one set running. Short runs may be two years and average is between 5 to 8 years. Also infant mortality can happen due to wrong installation, carefull clean of the threads and proper lubricant must be apply. I t may be a good idea to have the hydraulic torquing machine but not one per facility, better to be a share resource with several facilities.