assembly as shown in fig7 as clamp load is applied to the compressor wheel by rotating the nut to travel down the helix angle of the thread several events can happen the act of rotating the nut against the face 21 on the nose of the compressor wheel can cause the nut to dig into the face and track off center this tracking causes the mass center of the nut to move off the turbocharger axis which results in an unbalance n equal to the mass of the nut times the displacement r n perpendicular to the turbocharger axis this displacement also causes a bending of the stub shaft which results in yet another unbalance force s which is equal to the mass of the stub shaft 57 deviated from the turbocharger axis 35 times the displacement r s the bending of the stub shaft can also cause a displacement of the compressor wheel center of gravity which is indicated in fig7 as an unbalance force of u201c c u201d resisting these bending events is the interaction of the outside diametral surface of the stub shaft 61 which is a sliding fit with the inside diametral surface 26 of the hole 27 in the compressor wheel 20 aided by the compression of the clamp load applied by the interaction of the internal threads 32 in the compressor nut 30 against the threaded end 57 of the stub shaft 56 forcing the lower mounting face 22 of the compressor wheel against the stub shaft face contrary to the normal and widespread design and manufacturing protocol for machining a compressor wheel with the top surface 21 of the nose of the compressor wheel machined flat whereby to make flush contact with a flat bottomed nut 30 as shown in.