The advantages of mounting powder specimens free of any binder, adhesives, fibers, or tubes have led several workers to suggest methods and devices for extruding a tiny cylinder of powder. In one of the most recent of these (1), the powder is packed into a 19-gauge stainless steel tube with a plunger made of No. 22 steel wire. A demountable assembly maintains the alignment of anvil, specimen tube, and plunger.
R. Bruce Scott, "An Extrusion Method For Supporting X-Ray Powder Camera Specimens," Appl. Spectrosc. 15, 21-22 (1961)