Method of installing interference fit sleeved fasteners having radiused intersection for stress coining

A method for fastening at least two solid layers together, the layers having a first outer outside surface and a second outer outside surface, in an overlapping, parallel relationship comprising:

• forming a hole of a first diameter substantially perpendicular to the layers and passing completely through;
• forming an angled counterbore into the hole from the first outer surface wherein the counterbore remains in the first layer which defines the first outer outside surface;
• inserting a non-split, hollow constant wall thickness counterbore sleeve into the hole into a slip fit, the sleeve having a substantially constant thickness and two portions, the first portion is a counterbore portion and the second portion being straight walled portion, wherein the counterbore portion is formed to fit flush against the counterbore of the first layer and the straight walled portion is formed to fit flush against the first diameter of the hole, said sleeve is of uniform diameter and is of sufficient length to extend past the distal end of the hole and wherein the junction at the outer surface of the sleeve between the counterbore portion and the straight walled portion is a radiused intersection having a radius of about 0.030 to about 0.040 inches, after installation, the end of the counterbore portion opposite the junction is level with the first outer surface of the first layer;
• inserting a fastener into the inside of the sleeve, the fastener having a diameter sufficient to expand the sleeve into an interference fit with the hole in the layers and thereby stress coining the layer at the edge of the hole adjacent the radiused intersection of the sleeve;
• and
• operating upon the end of the fastener extending past the distal end of the straight walled portion of the sleeve to draw the radiused portion of the sleeve firmly against the abutting adjacent region of the intersection of the counterbore with the hole further stress coining the layer at edge of the hole and thereby fastening the layers together.

A method for fastening at least two solid layers together, these stacked together layers having a first outside surface and a second outside surface, in an overlapping, parallel relationship comprising:

• forming a hole of a first diameter substantially perpendicular to the layers and passing completely therethrough;
• inserting an assembly comprising a rivet within a non-split, collared constant wall thickness sleeve into the hole in a slip fit, the sleeve having a hollow, cylindrical portion with an inner and an outer diameter and first and second ends with a flange on the first end forming a collar and the second end extending past the distal end of the hole after insertion, wherein the junction between the outer diameter of the sleeve and the flange is defined by radiused intersection having a radius of between about 0.030 and about 0.040 inches said radius intersection is seated against the first outer surface of the layers at the edge of the hole;
• and
• upsetting the rivet to the extend wherein sufficient radial expansion of the rivet within the sleeve is created thereby causing an interference fit of the rivet and sleeve within the hole with stress coining of the layer at the edge of hole adjacent to the radiused intersection of the sleeve and thereby fastening the layers together.

A method for fastening at least two solid layers together, the layers having a first outer outside surface and a second outer outside surface, in an overlapping, parallel relationship comprising;

• forming an angled counterbore into the hole form the first outer surface wherein the counterbore remains in the first layer which defines the first outer outside surface;
• inserting an assembly comprising a rivet within a non-split, hollow counterbore constant wall thickness sleeve into the hole into a slop fit, the sleeve having a substantially constant thickness and two portions, the first portion is a counterbore portion and the second portion being a straight walled portion wherein the counterbore portion is formed to fit flush against the counterbore in the first layer and the straight walled portion is formed to fit flush against the first diameter of the hole, said sleeve is of uniform diameter and is of sufficient length to extend past the distal end of the hole and wherein the junction at the outer surface of the sleeve between the counterbore portion and the straight walled portion defining a radiused intersection having a radius of about 0.030 to about 0.040 inches, and after installation, the end of the counterbore portion opposite the junction is level with the first outer surface of the first layer, and the rivet fits closely within inside of the sleeve such that the head portion of the rivet at least completely fills the counterbore portion of the inside of the sleeve and the shank portion of the rivet extends sufficiently beyond the end of the straight walled portion of the sleeve to be effectively deformed during a succeeding upsetting operation;
• and
• upsetting the rivet to the extent wherein sufficient radial expansion of the rivet within the sleeve is created thereby causing an interference fit of the rivet and the sleeve within the hole with stress coining of the layer at the edge of hole adjacent to the radiused intersection of the sleeve and thereby fastening the layers together.