A nut is a metal with a spiral groove, a bolt is a metallic piece with a round stem
Fasteners come in many different forms. Bolts and nuts are used for joining wood in heavy wood construction (roof trusses and rafters), fastening heavy wood structures to iron constructions, a connection of parts on iron construction. Woodscrews are used for joining wood, fastening ironwork to wood, fastening hardware (hinges, locks, catches) to wood. A screw is a metal fastener with a spiral thread cut in. Carriage Bolts, Hex Head Bolts, Machine Screws, Shoulder Bolts, Socket Cap Screws, Socket Set "Grub" Screws, Square Head Bolts, Deck Screws, Hex Lag Screws, Self-Drilling Screws, Sheet Metal Screws, Wood Screws, Cap Nuts, Castle Nuts, Coupling Nuts, Flange Serrated Nuts, Hex Finish Nuts, Hex Jam Nuts, Heavy Hex Nuts, Hex Machine Nuts, Hex Machine Nuts Small Pattern, Keps-K Lock Nuts, Knurled Thumb Nuts, Nylon Hex Jam Nuts, Nylon Insert Lock Nuts, Prevailing Torque Lock Nuts (Stover), Slotted Hex Nuts, Square Nuts, Structural Heavy Hex Nuts, T-Nuts, Break Away or Shear Nuts, Tri-Groove Nuts, Wing Nuts.
Fasteners are used to secure or fasten materials together. There are many types of bolts and hardware nuts. Most, if not all, bolt types have machine threads. A threaded bolt screws into nuts to hold or fasten materials together.
Different Types of Fasteners. Mechanical fasteners come in many forms, including screws, nails, nuts, bolts, washers, anchors and rivets. Each of these different types of fasteners is a category unto itself, with many types to choose from.
Bolt types include eye bolts, wheel bolts, and machine bolts while types of nuts include cap nuts, expansion nuts, and u-nuts. A bolt is a mechanical fastener that is usually used with a nut for connecting two or more parts.
Thread Cutting Machine Screw
Sheet metal screw, hex head
Sheet metal screw, Phillips oval head
Wood Screws - Screws with a smooth shank and tapered point for use in wood.
Machine Screws - Screws with threads for use with a nut or tapped hole.
Thread Cutting Machine Screws - Machine screws with a thread cutting (self tapping) point.
Sheet Metal Screws - Fully threaded screws with a point for use in sheet metal.
Self Drilling SMS - A Sheet metal screw with a self drilling point.
Hex Bolts - Bolts with a hexagonal head with threads for use with a nut or tapped hole.
Carriage Bolts - Bolts with a smooth rounded head that has a small square section underneath.
Lag Bolts - Bolts with a wood thread and pointed tip.
Flange Bolts - Flange bolts have a flange on the bottom of the head that distributes the load like a washer.
Socket Screws - Socket screws, also known as Allen head, are fastened with a hex Allen wrench.
Eye Bolts - A bolt with a circular ring on the head end. Used for attaching rope or chain.
Eye Lags - Similar to an eye bolt but with wood threads instead of machine thread.
U-Bolts - Bolts in U shape for attaching to pipe or other round surfaces. Also available with a square bend.
J-Bolts - J shaped bolts are used for tie-downs or as an open eye bolt. Shoulder Bolts - Shoulder bolts (also known as stripper bolts) are used to create a pivot point.
Elevator Bolts - Elevator bolts are often used in conveyor systems. They have a large, flat head.
Sex bolts - (a.k.a. barrel nuts or Chicago bolts) have a female thread and are used for through bolting applications where a head is desired on both sides of the joint.
Mating Screws - Mating screws have a shoulder that matches the diameter of the sex bolts they are used with.
Hanger Bolts - Hanger bolts have wood thread on one end and machine thread on the other end.
Set Screws - Machine screws with no head for screwing all the way into threaded holes.
Drive Types
Phillips - The standard drive type for most screws.
Frearson - Similar to Phillips. Requires a Frearson driver for installation.
Slotted - A slot in the head.
Combination - A combination of slotted and Phillips drives.
Socket, Hex or Allen - A hexagonal hole for use with an Allen wrench.
One Way - Installs with a normal slotted driver but can not be removed without special tools.
Square - Also known as Robertson drive.
Star - Also known as Torx®. A six-pointed star pattern, specifically designed to prevent cam-out and stripped heads.
Head Styles
Flat - A countersunk head with a flat top.
Oval - A countersunk head with a rounded top.
Pan - A slightly rounded head with short vertical sides.
Truss - An extra wide head with a rounded top.
Round - A domed head.
Hex - A hexagonal Head.
Hex Washer - A hex head with built in washer.
Slotted Hex Washer - A hex head with built in washer and a slot.
Socket Cap - A small cylindrical head using a socket drive.
Button - A low profile rounded head using a socket drive.
Nut Types
Hex - A six sided nut. Also referred to as a finished hex nut.
Nylon Insert Lock - A nut with a nylon insert to prevent backing off.
Also referred to as a Nylock
Jam - A hex nut with a reduced height.
Nylon Insert Jam Lock - nylon lock nut with a reduced height.
Wing - A nut with 'wings' for hand tightening.
Cap - A nut with a domed top over the end of the fastener.
Acorn - Acorn nuts are a high crown type of cap nut, used for appearance.
Flange - A nut with a built in washer like flange.
Tee - A nut designed to be driven into wood to create a threaded hole.
Square - A four sided nut.
Prevailing torque lock - A non-reversible lock nut used for high temperature applications
K-Lock or Kep - A nut with an attached free-spinning external tooth
2-Way Reversible Lock - A lock nut that can be installed either side up. Often used in high temperature applications.
Coupling - Coupling nuts are long nuts used to connect pieces of threaded rod or other male threaded fasteners.
Slotted - Slotted nuts are used in conjunction with a cotter pin on drilled shank fasteners to prevent loosening.
Castle - Castle nuts are similar to slotted nuts but with the slots in a rounded section above the main nut
Washer Types
Flat - A flat washer used to distribute load. Available in SAE, USS, and other patterns.
Fender - An oversize flat washer used to further distribute load especially on soft materials.
Finishing - A washer used to obtain a 'finished' look. Usually used with oval head screws.
Split Lock - The most common style of washer used to prevent nuts and bolts from backing out.
External Tooth Lock - washer with external 'teeth' Used to prevent nuts and bolts from backing out.
Internal Tooth Lock - A washer with internal 'teeth' Used to prevent nuts and bolts from backing out.
Square - A square shaped washer.
Dock - Dock washers have a larger outside diameter and are thicker than standard.
Ogee - Thick, large diameter, cast iron washers with a curved or sculpted appearance. Typically used in dock and wood construction
Sealing - A neoprene washer bonded to a metal backing. Used to seal out air/water or dampen noise and vibration.
