Abstract: A screw assembly is made up of a screw and a screw fixing member. The screw fixing member is inserted into a starting hole formed in a concrete wall and then the screw is driven into the fixing member in a continuous manner. The screw fixing member has a body having a cylindrical section formed with an eccentric bore having an opening at one end thereof. The screw has its tip inserted in the opening of the bore. The screw has a threaded shank and a cylindrical portion provided at one end of the shank. The screw and the screw fixing member are coupled together by inserting the cylindrical portion of the screw into the opening of the bore.

Abstract: A screw fastener helps secure a tapping screw easily and strongly to a wall. A starting hole is formed in a wall. The trunk of the screw fastener is inserted into the starting hole. The trunk has such a shape that it comes into contact with the inner surface of the wall defining the starting hole. A tapping screw is driven into the screw fastener thus inserted in the starting hole. The threads on the screw will bite into both the wall and the trunk so that the screw will be rigidly fastened to the wall.

Abstract: Long and short legs have heads and pointed tips, respectively. They are joined together near their tips by welding. An upper portion above the welded portion of the long leg is formed with a cut extending obliquely upwards toward the short leg so that a thin breakable portion is formed in the long leg between the end of the cut and the contact surface with the short leg. A washer for clamping the legs above the cut is provided. When the nail is driven, the legs will not spread until the head of the short leg abuts the washer. When the head abuts the washer, the long leg slides outwards and spreads apart from the short leg near the cut. The breakable portion will thus get broken and the nail will spread.

Abstract: A tapping screw has a threaded shaft and a stepped drill bit portion including two or more drill portions having different diameters gradually decreasing toward the tip of the screw. The small-diameter drill portion has a larger drill angle than the large-diameter drill portion. The former firstly forms a starting hole and the latter expands it. Thus, less force is required to rotate the screw than a conventional tapping screw. Recesses are provided in the drill bit portion and have respective sides defined by cutting edges extending across only the portion of the thread closest to the tip of the tapping screw.

Abstract: A tape for holding nails has a side wall and upper and lower walls extending from both longitudinal edges of the side wall to the same side. The upper wall is formed with notches which open to the longitudinal side edge of the upper wall to hold nail shanks at their upper part near their heads. A fold-back wall is integral with the lower wall and folded back so as to oppose the top surface of the lower wall. The lower wall and the fold-back wall are formed with notches which open to the fold-back edge between the lower wall and the fold-back wall to hold the nail shanks at the lower part neat their tips. Instead of providing the fold-back wall, the top surface of the lower wall may be partially thickened at least at inner end portions of the notches.

Abstract: A pair of nail shank pieces are united face to face through the intermediary of a strip metal, and the tip parts of both nail shank pieces are tapered so that both nail shank pieces may be gradually opened as the nail is driven in. The metal strip is subjected to a compressive deformation to support the nail shank pieces from inside, thereby helping in their maintaining an opened state. Both nail shank pieces engage the base material in a dovetail fashion and in this way, the countering force against the nail's coming out is reinforced. A clamping ring fit around the outer circumference of both nail shank pieces to hold the metal strip therebetween such that both nail shank pieces are prevented from opening at the base material surface, and moreover, the opening made by the nail at the base material surface is protected from widening, while aiding in both nail shank pieces entering deep into the base material.