string 13 will normally have been deployed by drilling the wellbore at the same time the liner string 13 is being lowered into the well referring to fig1 c a cementing retainer profile 17 such as an annular recess is also located near the lower end of casing string 13 during liner drilling a bottom hole assembly bha 19 extends from the lower end of liner string 13 bha 19 is shown in dotted lines because it will be retrieved in this example before the cementing occurs bha 19 includes a drill bit 21 and normally additional equipment such as an underreamer and optionally surveying instruments and directional drilling equipment liner string 13 also includes a torque or profile sub 23 fig1 b which is near the upper end of liner string 13 in this embodiment torque sub 23 has an internal profile 25 such as vertical splines a liner running tool 27 releasably secures an upper section of a work string such as drill pipe 26 fig1 a to torque sub 23 of liner string 13 for transmitting torque to liner string 13 and supporting the weight of liner string 13 a lower drill pipe section 28 fig1 c extends downward from torque sub 23 through liner string 13 and is secured to bha 19 rotating drill pipe 26 fig1 a by a drilling rig not shown will cause lower drill pipe section 28 to rotate bha 19 applying drilling.