coating 310 may be applied along with a solvent which reduces the viscosity of the mixture to an application viscosity i e thins the mixture so it can be applied more easily to the thread surfaces typical organic solvents that may be used in the coating mixture include but are not limited to 2 methoxy 1methyl ethyl acetate xylene acetone tetrahydrofuran methyl ethyl ketone ethyl acetate propyl acetate butyl acetate isobutyl acetate methyl isobutyl ketone methyl amyl acetate diisobutyl ketone ethylene glycol monomethyl ether acetate ethylene glycol monoethyl ether and mixtures of the above after application of the first coating 310 on the thread surfaces the solvent typically evaporates from the mixture leaving the first coating 310 as a layer on the thread surfaces first coating 310 may generally be applied to specific regions of the thread surfaces namely thread crest surfaces 304 and substantially central regions 302 a of the thread root surfaces 302 first coating 310 may be applied only to substantially central regions of thread roots surfaces 302 due to the application method of the first coating 310 and limitations imposed by the structure of wedge threads first coating 310 may generally be applied in a radial direction to the threads e g in a direction substantially perpendicular to central axis 305 the radial direction may be employed as it may produce a more uniform distribution at the root surface thus requiring fewer passes applying subsequent coatings because of this particular application method the structure of the thread form may impose limitations as to the regions of the thread form to which.