Flush-break blind fastener

1. A fastener comprising:

a nut comprising a body, a first end, and a second end, wherein the body comprises an internally threaded bore having a first diameter, and the second end comprises a head comprising a wrenching surface, and a bore comprising a second diameter, wherein the first diameter is different from the second diameter;

a bolt comprising a bolt head, a first threaded portion, a second threaded portion, and a non-threaded portion, wherein the non-threaded portion is disposed between the first threaded portion and the second threaded portion, and wherein the first threaded portion comprises different dimensions than the second threaded portion;

a sleeve disposed between the bolt head and the nut; and

an insert operatively disposed between the sleeve and the bolt;

wherein the bolt passes through the sleeve, the insert, and the nut.

2. The fastener of claim 1 , wherein the bolt further comprises a groove disposed between the non-threaded portion and the second threaded portion.

3. The fastener of claim 2 , wherein the groove comprises a first wall and a second wall.

4. The fastener of claim 3 , wherein the first wall is generally planar and the second wall extends at an angle from the first wall.

5. The fastener of claim 4 , wherein the angle is between generally twenty-five degrees and forty degrees.

6. The fastener of claim 4 , wherein the angle is generally thirty degrees.

7. The fastener of claim 1 , wherein the nut further comprises a shoulder separating the internally threaded bore and the bore of the head.

8. The fastener of claim 7 , wherein the shoulder operatively stops the bolt from advancing beyond a predetermined position.

9. The fastener of claim 1 , further comprising a drive nut comprising a bore and an engaging surface operatively contacting the wrenching surface.

10. A fastener comprising:

a nut, a bolt, a sleeve, and a drive nut, wherein the drive nut comprises a knurled surface that interfaces with the nut and the nut, the sleeve, and the drive nut coaxially receive the bolt,

wherein the drive nut comprises a stop feature that prevents the bolt from advancing beyond a predetermined positon, and

wherein the bolt comprises a non-threaded portion with an annular break groove disposed within the non-threaded portion and wherein the non-threaded portion is operatively exposed during installation so that the bolt fractures with a flush, recess-free finish relative to the nut when the stop feature is engaged.

11. The fastener of claim 10 , wherein the nut comprises an engaging surface that: (i) is free of recesses or protrusions and (ii) interfaces with the knurled surface.

12. The fastener of claim 10 , wherein the annular break groove is initially positioned within the nut and wherein a diameter of the bolt at the non-threaded portion that is outside of the annular break groove is smaller than a diameter of the bolt.

13. A method comprising:

providing a blind fastener comprising a nut and a bolt having: (i) a first threaded portion, (ii) a second threaded portion, and a non-threaded portion disposed between the first threaded portion and the second threaded portion and (iii) an annular break groove disposed completely within the non-threaded portion, and wherein the first threaded portion comprises different dimensions than the second threaded portion;

positioning the blind fastener for installation within a work piece and rotating the bolt within the blind fastener until the bolt fractures when the non-threaded portion is exposed and the fastener is installed; and

wherein the installed fastener after breaking off the bolt comprises a recess-free, flush surface relative to a surface of the work piece.

14. The method of claim 13 , further comprising grasping the first threaded portion and applying force to the first threaded portion until breaking of the bolt.

15. The method of claim 14 , further comprising providing a drive nut, wherein the blind fastener further comprises a nut, and wherein the drive nut interfaces with the nut.

16. The method of claim 14 , further comprising providing an installation tool comprising a head, wherein the blind fastener further comprises a nut, and wherein the head interfaces with the nut.