18 34 in length as shown in fig1 a in an alternative embodiment of drill collar 10 shown in fig1 the entire body section 12a may be of the same outside diameter of the fishing neck 20a the bsr applies to the rotary shouldered connection or the threads connecting the drill string components with the outside diameter of the box primarily controlling the bending strength ratio the outside diameter of the pin section and the outside diameter of the body can be reduced without reducing the bending strength ratio hence the larger outside diameter of the box needs to be only a few inches in length i e sufficient in length to strengthen the box threaded connection a sufficient length to allow the box connection to be reworked several times is normally used when the body section diameter is the same as or less than the diameter of the pin section as shown in the case of body section 12b of drill pipe 10b of fig1 b the body section can be washed over without milling off any steel or the structure of the body section described above and shown in the fig1 can be left alone and at a.