Wing Nuts – Purpose, Size, Material Grades, & Alternatives

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Wing nuts distinguish themselves by the presence of two tabs. The tabs enable hand tightening/loosening for installation/removal. In this article, you will learn about the working principle of wing nuts, sizes, material grades, and alternatives.

How Wing Nuts Work

Wing Nut on wood

Wing nuts work like most other nuts: in conjunction with a bolt, they produce tension to hold two or more objects together. They twist onto the end of a bolt to prevent the connected objects from separating.

Wing nuts are available in the blank, tapped, and tapped through-hole versions. They typically possess a hot-stamped, matte shot-blasted finish. Slight dimples on the ends permit better grip and provide an increased finger contact area. Manufacturers provide blank versions that tap or ream in inch or metric sizes per customer requirements.

General overall benefits of include corrosion resistance, simplicity of installation/removal, and the lack of a heat treatment requirement.

The “wings” on these fasteners make it easier to tighten and loosen them. When a part requires frequent assembly and disassembly, wing nuts provide a strong option. It is possible to use them with or without a washer. Some varieties have a washer tack welded onto the bottom. Wing nuts are also popular for situations where convenience is essential, such as on boats and bicycles, due to their ease of usage.

Sizes of Wing Nuts

The nominal thread diameter of a wing nut refers to its size. The diameters typically vary from #6 to 3/4″. Sizes smaller than 1/4″ indicates a numerical size (the greater the number, the larger the size), but sizes 1/4″ and more significant specify in inches, which are frequently fractional rather than decimal.

Material Grades

Common materials are 18-8 stainless steel, 316 stainless steel, aluminum, brass, silicon bronze, and steel.

Common material grades are type A, C, and D. The alpha categorization provides intel on how the manufacturing process of the nut.

  • Type A: These cold forged wing nuts categorize by duty requirement: light, regular, or heavy series. Cold forging provides a more economical option than hot forging as the energy requirements brought on by heating does not apply.
  • Type B: These hot forged wing nuts also categorize by duty requirement: light, regular, or heavy. Hot forged wing nuts provide more ductility than their cold forged counterparts.
  • Type C: These die-cast wing nuts fashion from carbon steel with a zinc finish on them.
  • Type D: These fasteners form via a stamping process. Their physical properties are similar to cold forged wing nuts but lack the same strength.

In general, wing nuts are not considered a heavy-duty application. They see infrequent use in critical connections and are more appropriate for non-critical connections.


Thumb Nut

close up photo of thumb nut
Courtesy: PTS-UK.

A thumb nut provides similar functionality to the wing nut. It typically provides a ridged exterior flange that may be tightened by hand or with pliers. Thumb nuts do not apply to structural applications and tighten and loosen by hand.

They’re commonly found on computer cases and other places where quick access without the use of tools is sought.

Conventional Nuts

different sized of conventional nuts in one photo
Courtesy: Metal Industries

Conventional nuts require the use of a tool such as an impact wrench or hand wrench to secure the bolt. Industrial applications see much greater use of conventional nuts as they are more suitable for stressed connections. Conventional industrial nuts can be further categorized as coupling, flange, hex, lock, slotted, and square.

  • Coupling nuts – These internally threaded hex-shaped nuts connect two male threads.
  • Flange nuts – Have a broad, serrated flange on one end that functions similarly to a washer but without the extra movement.
  • Hex nuts – The most common type of nut which has a hex shape with internal threads.
  • Locknuts – Includes designs that avoid vibration-induced loosening.
  • Slotted nuts – These nuts provide a Cotter pin to produce a locking mechanism.
  • Square nuts – The square design allows for more surface area.

Material of construction and material grades vary depending on the expected application.