entire base of blade 110 c is fixed to e g formed with or welded to the head of screw member 102 the circumferential fixed length f shown in fig6 h is less than the largest circumferential length of the bottom of blade 110 c blade 110 c forms ears or tabs 112 c and 114 c here circular shaped that will tend to be bent or deformed upon insertion of blade 110 c into the second workpiece causing ears or tabs 112 c and 114 c to provide a counteracting locking force or stress against the gouged out inner wall of the second workpiece the force acts as a locking force to hold the second workpiece onto blade 110 c and consequently to hold the second workpiece fixed to the first workpiece circumferential fixed length f is again chosen to provide a desired combination of i rigidity to blade 110 c for ease of insertion into the second workpiece and ii flexibility to blade 110 c for locking blade 110 c and fastener 100 c to the second workpiece once inserted into same fastener 100 d of fig6 g to 6i also includes a blade 110 d that has a rolled shape here a diamond like shape blade 110 d is formed with or welded to screw portion 102 here again less that the entire base of blade 110 d is fixed to e g formed with or welded to the head of screw member 102 the circumferential fixed length f shown in fig6 k is less than the largest circumferential length of the bottom of blade 110 d blade 110 d forms ears or tabs 112 d and 114 d here tapered triangular shaped that will tend to be.