Different Types of Nuts and Their Uses
Nuts are a crucial hardware fastener used in many applications to join two or more parts together. There are many different types of nuts, each with unique properties and intended uses.
Hex Nuts
The most common type of nut, hex nuts are six-sided and available in different sizes. They can be paired with bolts or threaded rods in machinery, construction, vehicles, and other equipment. Some examples include:
- Finishing hex nuts - Used for general applications
- Jam nuts - Used to lock adjustments in place
- Coupling nuts - Used to connect threaded rods
Wing Nuts
Wing nuts have flanges or "wings" that protrude, making them easy to tighten and loosen by hand without tools. They are commonly used in furniture and appliances where frequent assembly or disassembly is needed.
Cap Nuts
Cap nuts feature a domed outer surface and are ideal for applications where the nut head needs to be covered or smoothed. Some examples of using cap nuts include:
- Finishing exposed threads on furniture
- Covering sharp edges on bolts
T Nuts
T nuts, also called tee nuts, have a flange that forms a T shape. The flange fits into a slot or groove in the part being fastened. This allows the nut to be embedded for an end or edge connection.
Coupling Nuts
Coupling nuts are elongated to allow bolting together successive threaded rods or screws. They are often used in:
- Conveyor systems
- Scaffolding
- Construction equipment
Jam Nuts
As mentioned previously, jam nuts are used to lock components like bolts and adjustable parts in position. The jam nut is tightened against a standard nut to prevent loosening over time due to vibration.
Flange Nuts
Flange nuts are similar to wing nuts in that they have a flange for easy finger grip. However, the flange is thinner and designed primarily to prevent spinning rather than aid tightening. Flange nuts are popular in the automotive industry.
As you can see, there are many types of nuts, each suited for specific applications and uses. Understanding the differences allows you to select the optimal nut type for your project.
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Choosing the Right Nut for Your Project
Choosing the proper nut is key to creating a safe and secure connection in your project. The wrong nut can lead to bolt failure, breakage or loosening. Here are some tips for selecting the best nut type and size.
Consider the Use Case
The nut application will dictate what type to use. For example:
- General connections - hex nuts
- Frequent assembly/disassembly - wing nuts
- Exposed threads - cap nuts
- Embedded connections - T nuts
Nut Strength
Nuts are available in different strength grades. Higher grades are stronger and more wear resistant. For heavy load applications, opt for grade 5, 8 or stronger nuts.
| Grade | Markings | Use Cases |
|---|---|---|
| Grade 2 | No markings | Light duty |
| Grade 5 | Three marks | Medium duty |
| Grade 8 | Six marks | Heavy duty |
Nut Size
Nut size must match the bolt diameter. Standard sizes include:
- 1/4"
- 5/16"
- 3/8"
- 7/16"
- 1/2"
Oversized nuts can slip and undersized nuts may not fit.
Thread Pitch
Choose nuts with a thread pitch that matches the bolt threads per inch. Common pitches are:
- Fine thread - 32 or 28 threads per inch
- Standard thread - 24 or 20 threads per inch
- Coarse thread - 16 or 13 threads per inch
Material
Steel nuts are suitable for most applications. Stainless steel provides corrosion resistance. Brass nuts can be used with softer metals like aluminum.
Paying attention to these key factors allows you to select the optimal nut for your specific project requirements.
Proper Nut Installation and Tightening Techniques
Installing nuts properly is critical to create secure connections. Follow these nut best practices and tightening methods to avoid failures.
Clean the Threads
Debris on bolt threads or nut contact surfaces can prevent tightening and loosening. Clean areas with a wire brush before installation.
Use Flanged Bolts When Needed
Flanged bolts have a collar under the head that "captures" the nut. This prevents spinning during tightening and ensures the nut stays in place.
Apply a Thread Locking Compound
For applications prone to vibration or loosening, apply a thread locker like Loctite to bolt threads before installing the nut.
Finger Tighten the Nut
Initially hand tighten the nut to get it started squarely on the threads.
Gradually Tighten in a Star Pattern
Use a calibrated torque wrench and tighten nuts in a crisscross star pattern in increments of 25-50% of full torque until reaching the target torque spec.
Use Jam Nuts for Adjustment Locking
For adjustable parts like valves or sensors, use a jam nut locked against a standard nut to secure the position.
Avoid Overtorquing
Excessive torque can overstress the fastener and damage parts. Do not exceed manufacturer torque ratings.
Re-Torque After Initial Operation
Nuts may loosen slightly after equipment starts operating. Recheck torque after a short initial running period.
Inspect for Damage
Look for cracks, stripping or thread galling. Discard and replace any damaged nuts.
Use Thread Lockers on Vibration-Prone Nuts
For nuts that may vibrate loose over time, apply a thread locking fluid like Loctite for extra security.
Proper nut installation and tightening will prevent loose, damaged or failed connections. Always use manufacturer torque specs and recheck critical applications.
Nut Grades and Strength Ratings
Nuts are manufactured in different grades that indicate their strength, hardness and load capacity. Using the proper nut grade for an application helps ensure a safe, secure fastening.
Nut Grading Systems
There are two main systems for rating nut strength:
- ASTM/SAE - Used for nuts 1/4" and larger
- ISO - Used for metric nuts and those under 1/4"
While the metrics differ slightly, both systems assign higher numbers for stronger grades.
Common ASTM Nut Grades
| Grade | Minimum Tensile Strength | Markings |
|---|---|---|
| Grade 2 | 74,000 PSI | No markings |
| Grade 5 | 120,000 PSI | Three marks |
| Grade 8 | 150,000 PSI | Six marks |
Metric Nut Strength Classes
| Class | Minimum Tensile Strength |
|---|---|
| Class 5 | 225 MPa |
| Class 8 | 640 MPa |
| Class 10 | 900 MPa |
| Class 12 | 1,000 MPa |
Choosing a Strength Grade
Use higher strength nuts for:
- High vibration applications
- Critical structural connections
- Large shear or tensile loads
Lower grades may be suitable for:
- Static loads
- Low stress connections
- Indoor furnishings
Consult engineering specifications to select the appropriate nut grade for expected service loads and conditions.
Corrosion Protection for Nuts
Nuts exposed to water, chemicals, or weather require protection against corrosion and seizing. Several methods can provide enhanced corrosion resistance for nuts.
Protective Coatings
Applying a coating creates a protective barrier between the nut and surroundings:
- Zinc plating - Electroplated zinc coating. Offers moderate corrosion resistance.
- Hot-dip galvanizing - Immersed in molten zinc. Provides very good outdoor corrosion protection.
- Epoxy coating - Multi-part epoxy paint evenly applied. Excellent chemical resistance.
Stainless Steel Nuts
Stainless steel nuts provide inherent corrosion resistance while maintaining high strength. Common grades used include:
- 304 - Good general corrosion resistance, some staining may occur.
- 316 - Added molybdenum for increased resistance in salty and acidic environments.
Lubrication
Applying a lubricant like oil, wax, or grease can displace moisture and prevent seizing or galling.
Anaerobic Adhesives
Thread locking adhesives like Loctite cure in the absence of air to seal threads. This prevents rust-causing moisture from penetrating.
Elastomeric Sealants
Flexible sealants like silicone can be applied to isolate and protect nut threads from exposure.
Anti-Seize Compounds
Anti-seize lubricants contain heavy metal additives that provide wetting and corrosion protection even under high temperature conditions.
Nylon Lock Nuts
A nylon collar in the nut threads prevents loosening while also sealing out moisture and chemicals.
Consider the operating environment and expected exposure to select the optimal corrosion protection method for your application.
Common Nut Sizes and Thread Pitches
Nuts are manufactured in many standard sizes and thread configurations to fit various bolts and applications. Understanding common nut dimensions helps ensure you choose the right fastener for your project.
Fractional Inch Nut Sizes
Fractional inch nuts come in coarse and fine thread pitches:
| Nut Size | Coarse Thread Pitch | Fine Thread Pitch |
|---|---|---|
| 1/4" | 20 threads per inch | 28 threads per inch |
| 5/16" | 18 threads per inch | 24 threads per inch |
| 3/8" | 16 threads per inch | 24 threads per inch |
| 7/16" | 14 threads per inch | 20 threads per inch |
| 1/2" | 13 threads per inch | 20 threads per inch |
Metric Nut Sizes
Metric nuts follow a standard thread pitch of 1.5mm between threads. Common sizes include:
- M3
- M4
- M5
- M6
- M8
- M10
- M12
Consult engineering drawings or your fastener supplier to identify the precise nut size and thread pitch for your application.
Tips for Removing Seized or Rusted Nuts
Over time, nuts may become rusted in place or seized onto bolts. Removing stuck nuts takes patience, but can be accomplished with some helpful techniques.
Use Penetrating Oil
Applying penetrating oil like WD-40 to the nut and letting it soak in for 10-15 minutes can help loosen bonding between the threads.
Tap Gently with a Hammer
Place a punch or chisel on the nut and lightly tap to help break the nut free. Be careful not to damage the threads.
Use an Impact Wrench
An impact wrench delivers quick hammer-like blows in addition to torque. This shock action can dislodge seized nuts.
Heat the Nut
Applying localized heat with a propane torch expands the nut which breaks the thread lock. Heat to around 250-300°F; excess heat risks damaging parts.
Chill the Nut
Freezing spray like difluoroethane can shrink and contract the nut to crack loose rust bonds. Avoid freezing surrounding machinery.
Cut the Nut
If needed, carefully cut the nut in two with an abrasive wheel or nut splitter. Take care not to damage the bolt threads.
Use Pickle Fork Extraction
A pickle fork wedge tool inserted behind the nut can help pop it off the bolt.
Replace Hardware
If nuts are severely seized, rusted or damaged, replacement of the nut and bolt is recommended for a reliable connection.
Stubborn seized or rusted nuts often require trying multiple tactics. Penetrating oil, impact tools, heat, and pickle forks are good options to try before resorting to cutting.
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How to Get an Amazon Prime Subscription for a Profit in Nuts (Hardware)
Amazon Prime offers fast free shipping and other benefits for online shoppers. While Prime costs $139 per year, there are a few creative ways you can get a paid Prime membership and actually profit from it if you sell nuts and bolts on Amazon.
Take Advantage of Free Prime Trials
Amazon offers a free 30-day Prime trial to new members. You can sign up for the free trial before listing your nuts and bolts products. This allows you to ship items for free and say "Prime Eligible" in the listing title during your trial period.
Only Ship Smaller Items
Prime shipping costs Amazon on average $3-5 per package. Only sell small, lightweight nuts and bolts that cost under $3-4 to ship. This ensures Amazon loses money shipping your Prime orders.
List Profitable FBA Products
Send your bestselling nuts in bulk to Amazon Fulfillment Centers. With Fulfilled by Amazon (FBA), Prime orders ship faster for free and Amazon handles storage, packing, and customer service. The extra exposure and faster shipping can increase sales to offset the Prime membership cost.
Reimburse Prime Membership
If you spend over $25,000 per year selling on Amazon, you can enroll in the Premium Selling Partner program. This reimburses the $139 Prime membership fee, so you profit from Prime benefits at no cost.
With some strategic shipping decisions and FBA product listings, you can leverage an Amazon Prime membership to actually boost profits selling nuts and bolts.
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What Are The Most Common Types Of Nuts Used In Hardware??
Here are the most common types of nuts used in hardware:
These nuts are used in conjunction with bolts to fasten multiple parts together. The type of nut used depends on the specific application and the type of bolt being used. It is important to choose the right type of nut to ensure a secure and long-lasting joint.
What Are The Differences Between Finished Hex Nuts And Semi-Finished Hex Nuts??
Finished hex nuts and semi-finished hex nuts are two types of hex nuts used in hardware. Here are the differences between them:
Finished hex nuts:
Semi-finished hex nuts:
The type of hex nut used depends on the specific application and the type of bolt being used. It is important to choose the right type of nut to ensure a secure and long-lasting joint.
