Chip break bolt head
Two piece tack rivets and method of forming holes for permanent fasteners. The tack rivets have a stem with a head on one end and a grooved region adjacent the other end, and a locking collar for fitting over the grooved region of the stem for deforming into the grooved region of the stem on applying a setting force between the locking collar and the stem. The head includes cutouts formed therein. The cutouts prevent the head from forming large chips or strips when drilled.
1. A tacking fastener for forming a hole for a permanent fastener, the tacking fastener comprising:
a stem comprising:
a first end comprising a head having transition portion terminating at a proximal edge of an insert portion;
a second end; and
a ribbed portion extending at least partially between a distal edge of the insert portion and the second end;
wherein the insert portion disposed between the first end and the ribbed portion and having a diameter that is greater than a diameter of the ribbed portion but smaller than a diameter of the head; and
a collar operatively attachable to the ribbed portion, said collar including an annular flange;
wherein the head comprises three or more cutouts each having a vertex and extending axially through a periphery of the head and through the transition portion to a junction of the insert portion and wherein the cutouts comprise a depth such that a deepest portion of a cutout is generally coplanar with a portion of the insert portion.
2. The tacking fastener of claim 1 , wherein the cutouts are equally spaced apart from each other.
3. The tacking fastener of claim 1 , the head comprises four cutouts.
4. The tacking fastener of claim 1 , the stem comprises an aluminum alloy.
5. The tacking fastener of claim 1 , wherein the cutouts comprise partially cylindrical recesses.
6. The tacking fastener of claim 1 , wherein the cutouts are generally cylindrical in shape.
7. The tacking fastener of claim 1 , wherein the cutouts comprise at least one of a V-Shape, a U-shape, or a rectangular shape.
8. The tacking fastener of claim 1 , wherein the head is integral with the insert portion.
9. The tacking fastener of claim 1 , wherein the head is separate from the insert portion.
10. The tacking fastener of claim 1 , wherein an end of the stem opposite the head is generally tapered.