X series casing
Flush-coupled casing tubes have a box thread at both ends and are connected together by a pin-to-pin coupling. This allows couplings to be replaced when pin threads become worn or damaged. It also means that the casing tube can have a thinner wall than the coupling, allowing the overall weight of casing string to be minimized. This can be important when drilling to greater depths.
W series casing
Flush-jointed casing has a heavier wall section than coupled casing and has an integral pin and box section. The heavier wall section provides internal and external mating shoulders for the threaded portion to butt-up against, providing twice the contact area of coupled casing and helping to prevent the threads climbing under heavy torque loads. This is by far the most popular type of casing used in geotechnical applications.
The smaller diameters B-H are manufactured from cold-drawn seamless steel tube and the larger sizes P-Z from hot-finished seamless tube, grade ST52 or higher. Casing drive plugs, and T.C. and diamond casing shoes are available for each size.
|Casing Type||Tube O.D Inches (mm)||Tube I.D. Inches (mm)||Coupling I.D. Inches (mm)||Threads per inch|
|NX||3.500" (88.9)||variable||3.000" (76.2)||8|
|HX||4.500" (114.3)||variable||4.870“ (123.7)||5|
|PX||5.500" (139.7)||variable||4.870“ (123.7)||5|
|SX||6.625" (168.3)||variable||5.875" (149.2)||5|
|BW||2.875" (73.0)||2.375" (60.3)||N/A||4|
|NW||3.500" (88.9)||3.000" (76.2)||N/A||4|
|HW||4.500" (114.3)||4.000" (101.6)||N/A||4|
|PW||5.500" (139.7)||5.000" (127.0)||N/A||3|
|SW||6.625" (168.3)||5.937" (150.8)||N/A||3|
|UW||7.625" (193.7)||7.000" (117.8)||N/A||3|
|ZW||8.625" (219.1)||8.000" (203.2)||N/A||3|
Casing available in 0.75, 1.5 and 3.0 metre lengths, other lengths available on request. Diameters may vary from above within tolerances specified by BS 4019.