Last updated on August 27th, 2026 at 11:06 am
Do you know how to select the right hardware for your precision sheet metal fabrication?
The right sheet metal hardware depends on what the fastener needs to do, the sheet material and thickness, required thread size, load, environment, installation method, and whether the hardware will be installed before or after finishing.
Many types of hardware can accomplish similar goals, but their designs and installation requirements vary significantly. Hardware may differ by type, material, thread code, shank length, overall length, locking method, and installation requirements.
Choosing the right option can feel complicated, but understanding the purpose of each hardware type makes the decision much easier.
8 Types of Hardware Used by Metal Fabricators
Let’s look at eight common hardware options for precision sheet metal fabrications:
- PEM® nuts and self-clinching nuts. PEM® is a PennEngineering brand commonly associated with self-clinching hardware. Self-clinching nuts are permanently pressed into sheet metal to provide strong, reusable internal threads without requiring a loose nut behind the panel.
- Standoffs. Standoffs create a controlled distance between components such as circuit boards, panels, covers, or brackets. Depending on the design, they may contain internal threads, external threads, or other mounting features.
- Studs. Self-clinching studs provide a permanently installed external threaded mounting point. They can simplify assembly by eliminating the need to insert a separate bolt through the sheet and are commonly used for brackets, electrical components, panels, and other attachments.
- Panel fasteners. Captive panel screws and similar hardware remain attached to the panel when loosened. They are especially useful for removable covers, access panels, and equipment that requires repeated servicing without loose hardware.
- TY-D tie-downs. Self-clinching tie-down hardware provides an integrated attachment point for cable ties and wire management. It eliminates the need to add adhesive-backed cable mounts or separate brackets after fabrication.
- Pins. Self-clinching pins provide an unthreaded locating, alignment, pivot, or mounting feature. They can be useful when a component needs to register to a repeatable position without using a threaded connection.
- Floating nuts and floating fasteners. Floating self-clinching fasteners allow limited movement of the threaded element so a mating screw can accommodate small positional variation between assembled components. They are especially useful on covers, enclosures, and assemblies where several fasteners need to line up at the same time.
- Locking nuts and locking fasteners. Locking hardware is designed to resist loosening in applications exposed to vibration, repeated movement, or other operating forces. The exact locking method and performance depend on the fastener design and manufacturer specification.
Quick Guide to Choosing Sheet Metal Hardware
| Design Need | Typical Hardware Option |
|---|---|
| Reusable internal thread in thin sheet metal | Self-clinching nut |
| Permanent external threaded mounting point | Stud |
| Create spacing between a panel and another component | Standoff |
| Frequently removable access panel | Captive panel fastener |
| Cable or wire management | Self-clinching tie-down |
| Alignment or locating feature | Pin |
| Compensate for mating-hole misalignment | Floating fastener |
| Resistance to loosening from vibration | Locking fastener |
Hardware Selection Depends on More Than Thread Size
Selecting self-clinching hardware requires more than deciding whether you need a #4-40, #6-32, M3, or another thread.
Engineers should also review:
- Sheet material
- Sheet thickness
- Sheet hardness
- Fastener material and hardness
- Mounting-hole diameter
- Shank code or fastener length
- Minimum edge distance
- Installation force
- Push-out resistance
- Torque-out resistance
- Corrosion and environmental requirements
These requirements vary by hardware family and part number, so always verify the manufacturer’s specifications before finalizing the design.
Sheet Thickness and Hardware Shank Code Matter
Self-clinching hardware must be compatible with the thickness of the sheet it is installed into.
If the sheet is too thin for the selected hardware, the fastener may not clinch properly or may protrude from the opposite side. If the fastener’s shank is too short for the sheet, it may not properly displace and capture enough material to achieve the intended retention.
For PEM® nuts and similar hardware, the shank or length code helps identify the appropriate fastener for a particular sheet thickness.
If you’re unsure which code to use, review our guide to selecting the correct hardware shank code.
Hardware Hole Size Is Critical
Self-clinching fasteners depend on a precisely sized mounting hole. During installation, the fastener displaces the surrounding sheet material so it flows into the fastener’s retaining feature.
If the hole is too large, the sheet may not provide enough material for the fastener to lock securely into place. If the hole is too small, installation can distort the sheet or damage the hardware.
Always use the mounting-hole diameter specified for the exact fastener manufacturer and part number.
ASM also provides a Hardware Hole Sizes Chart to help engineers quickly reference common sheet metal hardware requirements.
Keep Hardware Away from Bends and Edges
Hardware location affects both installation and forming.
A self-clinching fastener placed too close to a bend can:
- Interfere with press brake tooling
- Distort during forming
- Prevent the flange from sitting properly against the back gauge
- Deform the surrounding sheet during insertion
- Reduce the available material supporting the fastener
Hardware installed too close to an edge can also have reduced retention strength or cause the edge of the sheet to distort.
Do not rely on one universal edge-distance rule. Follow the hardware manufacturer’s minimum edge-distance, sheet-thickness, and installation requirements for the exact fastener being used.
Plan the Hardware and Finishing Sequence Together
Hardware installation should be considered along with powder coating, plating, anodizing, and other finishing operations.
Depending on the part, hardware may be installed before or after finishing.
Factors that influence the sequence include:
- Whether the hardware head should be coated
- Whether threads must remain free of powder or plating
- Whether the hardware provides an electrical grounding path
- Whether insertion after finishing could damage the coating
- Whether the selected hardware has its own finish requirement
- Manufacturer recommendations for installation
Providing the exact hardware part number and finish requirements early allows ASM to plan the fabrication and finishing sequence correctly.
Sheet Metal Hardware Hole Sizes Chart
CHART DOWNLOAD
Hardware hole sizes are the number one thing sheet metal fabricators have to fix before sending a part to the floor. So we have created a referenceable chart for product developers that are designing sheet metal parts. Use this chart to find the correct hole size for the hardware you select.
Common Mistakes in Hardware Selection
Selecting the wrong hardware for your precision sheet metal fabrication can cause installation problems, delayed production, poor retention, or unnecessary rework.
Here are some of the most common hardware design mistakes we see:
1. Using the Wrong Mounting-Hole Diameter
Incorrect mounting-hole size is one of the most common problems with self-clinching hardware.
The mounting hole should be based on the exact fastener part number, not simply the nominal thread size. Two fasteners with the same thread may require different installation holes.
Refer to the manufacturer’s specification or use our hardware hole-size guidance before releasing the design.
2. Selecting Hardware for the Wrong Sheet Thickness
Self-clinching hardware requires enough sheet thickness for the fastener to properly clinch into the material.
Always verify the manufacturer’s minimum sheet-thickness requirement and make sure the selected shank or length code matches your material thickness.
3. Ignoring Sheet and Fastener Hardness
Self-clinching hardware works by displacing the host material during installation. That means the fastener must generally be sufficiently harder than the sheet material for the clinching feature to embed correctly.
Hardware intended for aluminum or mild steel may not be appropriate for harder stainless sheet. Manufacturers offer different fastener families specifically for different sheet hardness ranges.
4. Placing Hardware Too Close to a Bend or Edge
Even when the hole diameter is correct, poor location can cause problems.
Hardware near a bend may interfere with press brake tooling or become distorted during forming. Hardware near an edge may not have enough surrounding material to achieve the required retention.
Follow the manufacturer’s specific edge-distance and installation requirements for the hardware family being used.
5. Choosing the Wrong Shank Code
Shank code is directly related to the thickness of the host sheet on many self-clinching fasteners.
A mismatch between shank length and material thickness can result in poor seating, inadequate retention, or hardware protruding where it should sit flush.
For more information, review our guide to finding the right hardware shank code.
6. Choosing the Wrong Hardware Material or Finish
Hardware material should be selected based on the sheet material, sheet hardness, corrosion environment, required finish, electrical requirements, and manufacturer recommendations.
A fastener that works well in aluminum may not be the best choice for stainless steel, and a hardware finish that works in a dry indoor application may not provide adequate protection in a corrosive environment.
Galvanic interaction between dissimilar materials should also be considered when the assembly will be exposed to moisture or other conductive environments.
7. Installing Hardware at the Wrong Stage of Finishing
Installing hardware before powder coating may cause coating buildup on threads or hardware surfaces. Installing it afterward may risk damaging the finished surface.
There is no universal sequence that works for every hardware type. The correct approach depends on the fastener, finish, grounding requirements, and customer specification.
8. Failing to Specify the Exact Hardware Part Number
A drawing note such as “#6-32 PEM nut” may still leave important questions unanswered.
The complete manufacturer part number communicates the exact hardware family, thread, shank, material, finish, locking style, and other attributes required for the part.
Providing that part number eliminates guesswork during quoting, purchasing, programming, and installation.
Hardware Cost Is More Than Piece Price
The lowest-priced fastener is not always the lowest-cost manufacturing solution.
When comparing hardware options, consider the complete installed cost:
- Hardware purchase price
- Installation labor
- Additional machining or tapping avoided
- Welding or secondary joining avoided
- Assembly time
- Masking or finishing requirements
- Risk of installation rework
- Future serviceability
- Replacement or maintenance requirements
A self-clinching fastener may cost more than a simple loose nut, for example, but it can eliminate backside access, simplify assembly, and provide a permanent reusable attachment point.
The best hardware choice is the one that meets the functional requirements while supporting an efficient fabrication and assembly process.
Choosing the Right Hardware for Your Precision Sheet Metal Fabrication
To choose the right hardware for your project, start with the function the hardware needs to perform.
Ask questions such as:
- Do I need an internal or external thread?
- Does the component need to be removable?
- Does the hardware need to maintain a specific spacing?
- Will several mounting locations need to align simultaneously?
- Will the assembly experience vibration?
- Does the hardware need to carry structural load?
- Will the part be exposed to moisture, chemicals, or temperature extremes?
- Does the hardware need to provide electrical continuity or grounding?
Once you know the hardware type, identify the appropriate hardware material for your application.
Material selection should account for:
- Base sheet material
- Sheet hardness
- Corrosion environment
- Required finish
- Electrical requirements
- Hardware manufacturer recommendations
What Hardware Information Should Be on the Drawing?
Complete hardware specifications make quoting and manufacturing much easier.
Whenever possible, identify:
- Hardware manufacturer
- Complete part number
- Thread size
- Quantity
- Installation location
- Installation side or orientation
- Hardware finish
- Whether installation occurs before or after finishing, when critical
- Any functional or cosmetic requirements
The 3D model can show where the hardware belongs, but the drawing or BOM should identify exactly which hardware is required.
Get Hardware Selection Right Before Production
Choosing hardware may look like a small part of a sheet metal design, but the selected fastener affects hole size, material thickness, forming, finishing, assembly, and final part performance.
That’s why it is worth confirming hardware early instead of waiting until the parts are already on the shop floor.
Choosing the wrong hardware can be a costly mistake, so we recommend working with a sheet metal fabrication shop to confirm your plans.
If you’re looking for a precision fabrication partner that can help with everything from hardware type and material to shank codes and hole sizes, give ASM a shot on your next project.
