The slight viscosity of the moving gas along with its adhesion to the disks' faces combine to drag them along, efficiently transferring the fuel's energy to the disks and on to the shaft. Fabrication of the runner is fairly straight forward. The parts are assembled with the aid of a stub shaft that has three keyways machined in it to line up with three complimentary keyways machined in the center hole of each disk. The stub shaft's length should be about three times the intended width of the runner. One end of the shaft is threaded and a shoulder ring is fastened just over a third of the way in from that end.
Assembly begins by slipping one of the thicker end disks on to the shaft.
With the rivets inserted the first set of spacers are installed followed by the first thin disk. Additional spacers and disks are added in sequence with the second end disk going on last. The next step is trueing up of the runner's width with a surface cut across the faces of the two end disks. While it is not as critical, the runner's outside circumference can also be trued up at this point. Care should be exercised here to reduce the chance of damage.