37 Repair and maintenance of downhole tools and assemblies used in the drilling of oil and gas wells; repair and maintenance of drill string components, namely, stub welding, OD/ID buildup and hardfacing; turning, drilling, milling, boring, threading, burninshing, welding and applying hardfacing/hardbanding material to oilfield down hole tools; lease and rental of oil well drilling and production tools, namely, drill collars, stabilizers, subs, hole openers, float valves, baffle plates, sleeves, and drillpipe screens