The disclosure provides a bolt including a main body, a head portion and a thread portion. The main body has a central axis. The head portion connects the main body. The thread portion is connected to the main body and runs around the central axis. The thread portion has a bearing surface facing toward the head portion. The bearing surface is a continuous curved surface or has an inflection point. The bearing surface includes a concave curved surface, a convex curved surface and a flank surface. The concave curved surface connects the main body. The convex curved surface is located further away from the main body than the concave curved surface. One side of the convex curved surface connects the concave curved surface, and another side of the convex curved surface connects the flank surface.

An aircraft monument floor attachment stud may include a body configured to pass through an opening of an aircraft monument, and a head. The body may include a body diameter. The body may be configured to couple to a fitting inserted into a mount point installed within an aircraft cabin floor. The head may include a tool section with a tool section diameter less than the body diameter. The tool section may be configured to receive a predetermined amount of torque from a tool to secure the aircraft monument to the fitting. The head may include a shaped section with an intermediate diameter greater than the tool section diameter and less than the body diameter. The shaped section may include at least one shaped portion with at least one sloped wall, and may be configured to provide a transition between the tool section diameter and the body diameter.

An interlocking thread with a tooth-cross-section that is wider at its crest than at its root and with “V” angles located both along the crest and the root which tightens into a tapped hole that has a similar thread cross-section.

An interlocking thread with a tooth-cross-section that is wider at its crest than at its root and with “V” angles located both along the crest and the root which tightens into a tapped hole that has a similar thread cross-section.

A fastener includes: a shaft having longitudinal axis and a first and second threaded portions, the first and second threaded portions separated by a central portion having a reduced diameter between the first and second threaded portions, and at least one of the first or second threaded portions is chamfered to reduce friction on leading threads.

A fastener includes: a shaft having longitudinal axis and a first and second threaded portions, the first and second threaded portions separated by a central portion having a reduced diameter between the first and second threaded portions, and at least one of the first or second threaded portions is chamfered to reduce friction on leading threads.

A multi-material boss, configured for fastening of a fastener thereto, being a feature of a die cast part, comprising a boss cylinder, an augmenting cylinder, and a filler metal layer is provided. The boss cylinder is made of the same material as the die cast part having a first hardness, and has a first interior. The augmenting cylinder is made of an augmenting material having a second hardness, is fixedly secured in the first interior of the boss cylinder, and has a second interior defined by a second cylindrical shaped wall, a base rim, and a second opening. The second hardness is greater than the first hardness. The fastener is fastened to the multi-material boss via the second opening of the augmenting cylinder having the higher liquidus temperature and greater hardness.

A multi-material boss, configured for fastening of a fastener thereto, being a feature of a die cast part, comprising a boss cylinder, an augmenting cylinder, and a filler metal layer is provided. The boss cylinder is made of the same material as the die cast part having a first hardness, and has a first interior. The augmenting cylinder is made of an augmenting material having a second hardness, is fixedly secured in the first interior of the boss cylinder, and has a second interior defined by a second cylindrical shaped wall, a base rim, and a second opening. The second hardness is greater than the first hardness. The fastener is fastened to the multi-material boss via the second opening of the augmenting cylinder having the higher liquidus temperature and greater hardness.

A locking system comprising a block made of a polymer substance having an upper surface and a lower surface. In a normal condition, the block has the following structure. A bore, having a first axis, extends through the block and passes through the upper surface and the lower surface, the bore being shaped to include a taper, whereby an upper end of the bore has a larger diameter than a lower end of the bore, and the bore has an internal surface that is smooth. And, a slot, having a second axis, extends through the block and passes through the upper surface and the lower surface, the slot having a generally planar configuration with a width and a thickness, the slot being positioned such that the first axis and the second axis are co-axial, whereby the slot and the bore form a single continuous opening extending through the block.

A locking system comprising a block made of a polymer substance having an upper surface and a lower surface. In a normal condition, the block has the following structure. A bore, having a first axis, extends through the block and passes through the upper surface and the lower surface, the bore being shaped to include a taper, whereby an upper end of the bore has a larger diameter than a lower end of the bore, and the bore has an internal surface that is smooth. And, a slot, having a second axis, extends through the block and passes through the upper surface and the lower surface, the slot having a generally planar configuration with a width and a thickness, the slot being positioned such that the first axis and the second axis are co-axial, whereby the slot and the bore form a single continuous opening extending through the block.