Boltwith hole

A system for re-threading stripped internal threads. A proprietary tap is used to re-thread the hole and a spring like insert is placed inside to make up the difference in width, allowing the original size bolt to be used

Used in reference to countersunk fasteners. This is the angle from one side of the cone to the other. Standard measurement is 82 degrees. Special 100 degree heads are also made.

A measurement of how much of the fastener is in the material being fastened. See Length of Engagement and Thread Engagement

The distance from one thread to the next along the length of the fastener. Used mostly in metric, where it is expressed in millimeters.

Cotter PinBolt and nut

A cone shaped end with a circular depression in the center. The contact area is thus a circular ridge. This is the most common point for set screws.

A nut with slots cut into it for the insertion of a cotter pin. Used with a drilled shank fastener. Similar to a castle nut.

A countersunk head that has been cut off at 70% of the normal height. Screws in this style will have a second flat surface parallel to the top just before the threads. Used frequently in extremely short screws to provide more thread.

A fastener with a full cone shaped point on the end. Often used in automated assembly to guide the fastener into the hole.

A fastener with a full cone shaped point on the end. Often used in automated assembly to guide the fastener into the hole.

Hexagon Boltswithsplitpin HoleonShank

A special tap for finishing the threads to the very bottom of a hole that does not pass through the material. A regular tap must be used first.

Thread that is formed opposite to normal thread so it tightens counter clockwise. Used on spinning equipment to prevent loosening. Generally custom made.

Used in metric, class is a material designation equivalent to the US term Grade (ex. Class 10.9). Also in US fasteners, a specification describing how tightly the fastener fits.

Boltwith Pin Hole

An unthreaded cylindrical tip that is smaller than the fastener diameter. Used to help speed alignment during assembly. Also called a Dog Point.

A fastener designed so it can be installed with a slotted screw driver but can not be removed. Used to prevent tampering.

Thread that is formed opposite to normal thread so it tightens counter clockwise. Used on spinning equipment to prevent loosening.

The tool used to create internal threads in a hole or the act of creating such threads. See also Bottom Tap, and Starter Tap.

An unthreaded cylindrical tip that is smaller than the fastener diameter. Used to help speed alignment during assembly. Also called a Pilot Point

Splitpin HoleBolt

Threads formed by tightly pressing or rolling the piece of stock between serrated dies. This is the most common method of creating threaded fasteners today.

ClevisPin

A type of lock nut where the top of the nut has been slotted and bent inward. When assembled the pressure on the threads prevents the nut from backing off.

A thin nut with a flange on one end. Intended to be inserted in a hole, in wood, with the flange on the surface. Used to allow a bolt to be fastened in wood without a protruding nut.

An abbreviation for Deutsches Institut für Normung, the German standards body. In reference to fasteners DIN indicates fasteners that conform to a specific metric standard (will be followed by the standard number).

A bolt with a smooth rounded head and a small square section under the head to prevent spinning during assembly. Used in wood.

The percentage of the thread height that is in the material being fastened. For full thread engagement the pilot hole should be equal to or smaller than the Root Diameter of the fastener.

A hex nut with a slightly reduced slotted cylindrical section on one end. Used with a cotter pin and drilled fastener to prevent loosening.

A bolt that has been heat treated all the way through. More brittle but stronger than a Case Hardened bolt. Also called Fully Hardened.