the present invention also shown in fig2 are a removable second stop 16 having circular access ports 17 a one piece outer sleeve 18 which is preferably provided with straight or spiral blades 21 a two piece inner sleeve 20 flanged at it 39 s lower end longitudinal dove tailed grooves 22 a formed on the inner surface of the outer sleeve 18 and longitudinal dove tailed integral splines 22 b formed on the outer surface of the inner bearing members 20 the second stop 16 is in the form of an annular ring 16 it should be noted that the dove tailed splines 22 b and grooves 22 a preferably do not extend the entire length of the sleeves as shown in fig2 and 3 the inner bearing members 20 are formed from two half cylinder shaped inner bearings 20 a and 20 b in order to assemble the friction reducing drill string component 1 the inner bearing members 20 a 20 b and are positioned around the mandrel body 5 within the mandrel body recess 13 c such that the flange is arranged at the lower in use end of the component 1 thereafter the one piece outer sleeve 18 is slid over the mandrel body upper neck 13 a after lining up the dove tailed grooves 22 a with the dove tailed splines 22 b outer sleeve 18 will slide over the inner bearing members 20 in a downward sliding manner until the lower end of the outer sleeve is rests directly on top of the.