In implementations of a pressure lock retention fastener, the fastener assembly includes an insert sized for insertion into a fastener hole in a first panel. The fastener assembly has a threaded collet sized to slide in the insert and has expandable flanges that extend below the insert. The expandable flanges are sized for insertion into an aligned hole in a second panel. The fastener assembly also includes a screw installable through the insert to engage the threaded collet. The screw exerts a force that pushes the expandable flanges outward as screw rotation drives the screw into the threaded collet, and ridge locks of the expandable flanges seat up against the second panel effective to fasten the panels together. In implementations, a plate is installable between the panels with slotted holes having anti-rotation tabs that prevent a fastener assembly from spinning in the panel holes.

A fastening nut device for fastening one substrate to another includes a cylinder, which is circumferentially larger proximate to a first end thereof, thus defining a first section and a second section of the cylinder. External threading, which is reversed, is positioned on the second section and extends from a second end of the cylinder. The cylinder can be inserted into a first hole positioned in a first substrate by counterclockwise rotation. The first section of the cylinder abuts a first face of the first substrate and the second end of the cylinder is accessible from a second face of the first substrate. A channel, which is internally threaded, extends into the cylinder from the second end. A threaded fastener, which is engaged to a second substrate, can be inserted by clockwise rotation into the channel to engage the second substrate to the second face of the first substrate.

In implementations of a pressure lock retention fastener, the fastener assembly includes an insert sized for insertion into a fastener hole in a first panel. The fastener assembly has a threaded collet sized to slide in the insert and has expandable flanges that extend below the insert. The expandable flanges are sized for insertion into an aligned hole in a second panel. The fastener assembly also includes a screw installable through the insert to engage the threaded collet. The screw exerts a force that pushes the expandable flanges outward as screw rotation drives the screw into the threaded collet, and ridge locks of the expandable flanges seat up against the second panel effective to fasten the panels together. In implementations, a plate is installable between the panels with slotted holes having anti-rotation tabs that prevent a fastener assembly from spinning in the panel holes.

A screwable device having a retractable threaded section that has a generally tubular shaft extending along a longitudinal axis and having a front section formed with a radially outwardly open aperture and a rear section. At least one locking element comprising a threaded section and being radially displaceable in the aperture between an outer position with the threaded section projecting radially outward from the shaft and an inner position in which the threaded section is recessed within the tubular shaft. An actuating is rod coaxially slidable in the shaft between a front position and a rear position, the actuating rod having a push-button at its rod rear end, the actuating rod having a structure for engaging the locking element in at least one of its positions pressing the locking element into the outer locking position.

A joint for a cutting tool includes a bolt with a head in a first end, with a thread in a second end, and with an intermediate section between the first end and the second end, which during attachment of two objects rotatably to each other protrudes trough openings in said objects. A nut is received on the thread. In order to provide an easy solution for adjusting the tension of the joint and at the same time preventing accidental loosening of the joint, the bolt is provided with a cavity. An expansion bolt with a threaded end protrudes into the cavity and expands the second end of the bolt.

A fastening nut device for fastening one substrate to another includes a cylinder, which is circumferentially larger proximate to a first end thereof, thus defining a first section and a second section of the cylinder. External threading, which is reversed, is positioned on the second section and extends from a second end of the cylinder. The cylinder can be inserted into a first hole positioned in a first substrate by counterclockwise rotation. The first section of the cylinder abuts a first face of the first substrate and the second end of the cylinder is accessible from a second face of the first substrate. A channel, which is internally threaded, extends into the cylinder from the second end. A threaded fastener, which is engaged to a second substrate, can be inserted by clockwise rotation into the channel to engage the second substrate to the second face of the first substrate.

A threaded installation is provided. The threaded installation includes a nut, a bolt, and a housing. The housing includes a threaded hole. A first threaded connection is formed where the bolt is threadably coupled with the nut, and a second threaded connection is formed where the bolt is threadably coupled with the threaded hole. The first threaded connection is characterized by a first flank angle, Θ.sub.2A, of threads of the bolt or threads of the nut. The second threaded connection is characterized by a second flank angle, Θ.sub.3B, of threads of the bolt or threads of the housing. The flank angles, Θ.sub.2A and Θ.sub.3B, satisfy the following equation: $k_2=\frac{\cos \left({\theta }_{2A}\right)}{\cos \left({\theta }_{3B}\right)}>1.00.$

A screwable device having a retractable threaded section that has a generally tubular shaft extending along a longitudinal axis and having a front section formed with a radially outwardly open aperture and a rear section. At least one locking element comprising a threaded section and being radially displaceable in the aperture between an outer position with the threaded section projecting radially outward from the shaft and an inner position in which the threaded section is recessed within the tubular shaft. An actuating is rod coaxially slidable in the shaft between a front position and a rear position, the actuating rod having a push-button at its rod rear end, the actuating rod having a structure for engaging the locking element in at least one of its positions pressing the locking element into the outer locking position.

A fastening tool system includes a housing including a main body having a proximal end and a distal end. The main body defines an internal chamber extending between a proximal opening at the proximal end and a distal opening at the distal end. A plunger includes a stem that extends into the internal chamber through the proximal opening. The plunger is configured to be moved in relation to the main body between a retracted position and an extended position. A securing stud is in a collapsed position when the plunger is in the retracted position. The plunger is configured to move into the extended position to engage the securing stud to expand the securing stud into an expanded position.

A threaded installation is provided. The threaded installation includes a nut, a bolt, and a housing. The housing includes a threaded hole. A first threaded connection is formed where the bolt is threadably coupled with the nut, and a second threaded connection is formed where the bolt is threadably coupled with the threaded hole. The first threaded connection is characterized by a first flank angle, .sub.2A, of threads of the bolt or threads of the nut. The second threaded connection is characterized by a second flank angle, .sub.3B, of threads of the bolt or threads of the housing. The flank angles, .sub.2A and .sub.3B, satisfy the following equation:

[00001]$k_2=\frac{\cos \left({}_{2.Math.A}\right)}{\cos \left({}_{3.Math.B}\right)}>1.0.Math.0.$