compressible material held together by an end collar or ring 20 each strip will of course be substantially equal in length but the circumferential extent of the strip 19 can be varied still another treatment of the formable material 21 is seen in fig6 where the circumferential extent of the material is greater than the circumference of the bore hole 10 in that event the material will buckle or it may be initially formed into a quasi clover leaf in cross section so that certain lobes 21a extend radially into the central area and intervening lobes 21b are in contact with the bore hole 10 when the threaded anchor bolt is inserted it will force the material of lobes 21a into conformation to create spiral wedges much like the character of spiral wedges to be formed in the case of the means 12 of fig2 still another treatment of the formable material is seen in fig7 where with sheet material 22 the circumferential extent of the material is greater than the circumference of the bore hole 10 in that event the material will overlap at 22a into the central area while still in contact with the bore hole when the threaded anchor rod is inserted it will force the material 22 into conformation.