Why Choose Micro Fasteners?
Micro fasteners are the right choice when the assembly requires a small-diameter threaded fastener and standard #6, #8, or larger screws are too big for the application. They are designed to deliver reliable clamping and thread engagement in tight spaces, thin materials, and precision assemblies where every millimeter of clearance matters.
This category includes micro screws, micro bolts, micro nuts, and micro washers in thread sizes from #0-80 through #4-40. Available in stainless steel, alloy steel, brass, and nylon, with a range of head styles and drive types to match the requirements of the assembly.
Common Uses for Micro Fasteners
Micro fasteners are commonly used in electronics assembly, printed circuit board mounting, optical instrument housings, camera bodies, eyeglass frames, medical device enclosures, robotics, RC vehicles, drone frames, computer hardware, precision instrument panels, and small mechanical assemblies.
They are also used for repair and maintenance of small consumer products, lab equipment, and any assembly where the fastener must fit into a confined space or thread into a small boss, insert, or tapped hole.
Micro Fastener Thread Sizes
Micro fasteners on this page are available in the following Unified National thread sizes:
- #0-80 (smallest diameter, 80 threads per inch)
- #1-64 (64 threads per inch)
- #1-72 (72 threads per inch)
- #2-56 (56 threads per inch)
- #2-64 (64 threads per inch)
- #3-48 (48 threads per inch)
- #3-56 (56 threads per inch)
- #4-40 (40 threads per inch)
- #4-48 (48 threads per inch)
Select the thread size based on the tapped hole or threaded insert in the mating part. The first number is the screw diameter designation and the second number is threads per inch. Finer thread counts (higher TPI) provide more thread engagement per unit of length and are often used in thin materials or where vibration resistance is important.
Micro Fastener Head Styles
Micro fasteners are available in multiple head styles. Choose based on the required bearing surface, the available drive access, whether the fastener will sit flush or proud of the surface, and the appearance requirements of the finished assembly.
Pan head micro screws provide a low-profile rounded head with a wide bearing surface and are commonly used in electronics and general small assembly. Flat head micro screws are countersunk and sit flush with the surface, useful when a smooth finished appearance is needed. Socket head cap screws provide a cylindrical head with a hex socket drive, commonly specified for precision mechanical assemblies and fixtures. Fillister head micro screws have a taller, narrower head with deep drive slots and are used when extra drive depth is needed in a small-diameter fastener. Button head micro screws offer a low dome profile and are often chosen for aesthetic applications.
Micro Fastener Drive Types
Micro fasteners are available with Phillips, slotted, hex socket (Allen), and Torx drive configurations. Choose the drive type based on the tools available, the torque required, and the access space around the fastener head during installation.
Phillips and slotted drives are common in consumer electronics and general repair. Hex socket drives are frequently used in precision mechanical assemblies and allow higher torque application in a small head. Torx drives provide good resistance to cam-out and are common in medical device and electronics manufacturing.
Micro Fastener Materials
Micro fasteners are available in stainless steel, alloy steel, brass, and nylon. Select the material based on the corrosion environment, the required strength, the electrical conductivity requirements of the assembly, and whether the fastener will be visible in the finished product.
Stainless steel micro fasteners (18-8 and 316) provide good corrosion resistance and are commonly used in medical, optical, marine, and outdoor applications. Alloy steel micro fasteners provide higher tensile strength and are used in mechanical assemblies where load capacity matters. Brass micro fasteners are electrically conductive, non-magnetic, and often chosen for electrical and electronic assemblies. Nylon micro fasteners are non-conductive, lightweight, and used where electrical isolation or resistance to chemicals is needed.
Stainless Steel Micro Fasteners
Stainless steel micro fasteners are available in 18-8 (304) and 316 stainless steel. 18-8 stainless provides good corrosion resistance for most indoor and moderate outdoor environments. 316 stainless provides better resistance to chlorides and salt exposure and is preferred for marine, coastal, and medical applications.
Choose stainless steel micro fasteners when corrosion resistance, appearance, or non-magnetic properties are important to the application.
Brass Micro Fasteners
Brass micro fasteners are electrically conductive, non-magnetic, and naturally resistant to corrosion in many environments. They are commonly used in electrical assemblies, RF and electronic enclosures, optical instruments, and any application where a non-ferrous, conductive fastener is specified.
Brass is a softer material than stainless or alloy steel. Avoid over-torquing brass micro fasteners, especially in very small diameters, to prevent thread stripping or head damage.
Nylon Micro Fasteners
Nylon micro fasteners are non-conductive, lightweight, and resistant to many chemicals and solvents. They are commonly used in circuit board mounting, electrical isolation applications, and assemblies where metal fasteners could cause a short circuit or interfere with sensitive components.
Nylon micro fasteners have lower tensile strength than metal options and are not suitable for applications requiring significant clamping load or exposure to high temperatures.
Micro Fasteners vs Standard Machine Screws
Micro fasteners cover thread sizes #0-80 through #4-40. Standard machine screws typically begin at #4-40 and go up through #6-32, #8-32, #10-24, 1/4-20, and larger.
Choose micro fasteners when the assembly design, hole size, or boss diameter cannot accommodate a #6 or larger screw. If a #4-40 fastener fits the application, compare both micro and standard machine screw options for the best availability and pricing.
Micro Nuts and Micro Washers
Matching micro nuts and micro washers are available for use with micro screws and bolts. Hex nuts, nylon insert locknuts, and flat washers in #0-80 through #4-40 sizes allow complete fastener assemblies to be built using micro-sized hardware throughout.
Use micro washers to distribute clamping load across thin or soft materials and to protect surface finishes under the fastener head or nut. Use nylon insert locknuts when vibration resistance is needed in the assembly.
How to Choose the Right Micro Fastener
Choose the micro fastener based on the thread size and pitch required by the mating hole or insert, the head style and drive type that fits the assembly and installation tool, the material that suits the corrosion environment and strength requirements, and the length needed to achieve proper thread engagement without bottoming out or protruding excessively.
As a general rule, aim for a minimum of 1.5 times the screw diameter in thread engagement for metal assemblies. In very soft materials or thin-walled bosses, consider threaded inserts to improve thread engagement and extend the service life of the tapped hole.
Related Categories
- Screws & Bolts
- Machine Screws
- Socket Head Cap Screws
- Nuts
- Washers
- Threaded Inserts
- Shop by Material
- Fastener Assortment Kits
Micro Fastener FAQs
What size are micro fasteners?
Micro fasteners on this page range from #0-80 (the smallest) through #4-40. These sizes are smaller than standard machine screws and are used in precision, electronic, optical, and medical applications where larger fasteners will not fit the assembly.
What is the difference between #0-80 and #4-40?
#0-80 is the smallest thread size in this category, with a nominal diameter of approximately 0.060" and 80 threads per inch. #4-40 has a larger nominal diameter of approximately 0.112" and 40 threads per inch. Choose the size based on the tapped hole or insert in the mating part.
What materials are micro fasteners available in?
Micro fasteners on this page are available in 18-8 stainless steel, 316 stainless steel, alloy steel, brass, and nylon. Choose based on strength requirements, corrosion environment, conductivity, and appearance.
Can I use micro fasteners in electronics assemblies?
Yes. Micro fasteners are commonly used in electronics assembly for circuit board mounting, enclosure assembly, and component attachment. Choose the material based on conductivity and isolation requirements. Nylon micro fasteners are non-conductive. Brass micro fasteners are conductive. Stainless steel is non-magnetic.
What tools do I need to install micro fasteners?
Micro fasteners require small precision screwdrivers, hex keys, or Torx drivers sized to match the drive type and head size. Use a torque driver when consistent torque is important, especially in medical, aerospace, or precision mechanical applications. Avoid over-torquing, particularly in brass or nylon micro fasteners.
Do you sell micro nuts and washers to match?
Yes. Matching micro nuts and washers are available in the same thread sizes. Browse the related categories above or contact us if you need help locating a specific size or material combination.
What is the minimum order for micro fasteners?
Micro fasteners are available in individual sizes with no minimum order requirement. Bulk pricing is available for large quantity orders. Contact us for pricing on high-volume or recurring micro fastener needs.