Board Spacers, Standoffs

Part Number	Description / PDF	Quantity
MF-300-UC25-SL20300 Aearo Technologies, LLC – a 3M company	RND STNDFF 1/4"-20 SYN RUB 5/8"	441
2081-440-B RAF	3/16_HEX_FEMALE_STANDOFFS	725
4532-440-SS-20 RAF	1/4 HEX X 3/8 LENGTH	632
4544-440-AL RAF	1/4 HEX X 1-1/8 LENGTH	490
2238-832-AL RAF	3/8 HEX X 1/2 LENGTH	3796
9118-75-B-12 RAF	ROUND SPACER BRASS 1-1/2"	24
960360116 Würth Elektronik Midcom	ROUND PLASTIC SPACER L:36,0 MM	464
971100154 Würth Elektronik Midcom	BRASS SPACER STUD METRIC THREAD	4386
970350327 Würth Elektronik Midcom	STAINLESS STEEL SPACER STUD METR	320
9774020151R Würth Elektronik Midcom	RND STANDOFF M2.5X0.45 STEEL 2MM	8940
13RS075043 Richco, Inc. (Essentra Components)	ROUND SPACER, .310 ID, .740 OD,	2000
960040042 Würth Elektronik Midcom	ROUND PLASTIC SPACER L:4,0 MM	3865
970180474 Würth Elektronik Midcom	BRASS SPACER STUD METRIC THREAD	742
3045-C-440-B-12 RAF	1/4 RD X 1/8 LENGTH	932
1625-3 Keystone Electronics Corp.	ROUND STANDOFF #4-40 BRASS 3/4"	988300
13RS050080 Richco, Inc. (Essentra Components)	ROUND SPACER, .380 ID, .500 OD,	2000
NAS43DD7-66FC RAF	ALUMINUM UNTHREADED SPACER .548-	0
970150321 Würth Elektronik Midcom	HEX SPACER M3X0.5 STEEL 15MM	482
M0904-A-25-AL-7 RAF	4.5MM RD X 5MM X 2.7MM ID	2500
SH1003-C Davies Molding, LLC.	HEX SPACER M4 NYLON 20MM	0

Board Spacers, Standoffs

1. Overview

Board spacers and standoffs are specialized hardware components used to create controlled spacing between printed circuit boards (PCBs), panels, or structural elements. They provide mechanical support, electrical isolation, and thermal management in electronic assemblies. Their importance in modern technology includes enabling compact designs, reducing vibration stress, and improving heat dissipation in devices ranging from smartphones to industrial control systems.

2. Main Types & Functional Classification

Type	Functional Features	Application Examples
Cylindrical Spacers	Simple tubular design with uniform diameter	PCB layer separation in consumer electronics
Hexagonal Standoffs	6-sided structure for wrench tightening	Industrial equipment panel mounting
Self-clinching Standoffs	Permanent installation with threaded compression	Sheet metal enclosures in servers
Adjustable Spacers	Variable length through threaded adjustment	Prototype development and testing
Insulated Spacers	Non-conductive materials for electrical isolation	High-voltage power supply assemblies

3. Structure & Composition

Typical construction includes:

Material: Stainless steel (corrosion resistance), aluminum (lightweight), or nylon (insulation)
Geometry: Cylindrical (standard), stepped (for multiple board heights), or flanged (for load distribution)
Installation Features: Internal threading (male/female), knurled surfaces (for grip), or press-fit tabs
Surface Treatment: Passivation (metal), UV resistance (plastics), or EMI shielding coating

4. Key Technical Specifications

Parameter	Importance
Material Hardness (HV)	Determines wear resistance and load capacity
Thread Engagement Length	Affects vibration resistance in dynamic environments
Thermal Conductivity (W/m K)	Critical for heat dissipation in power electronics
Dielectric Strength (kV/mm)	Safety factor in high-voltage applications
Installation Torque Rating	Prevents over-tightening damage to PCBs

5. Application Fields

Primary industries include:

Electronics Manufacturing: Server racks, LED displays
Automotive: Engine control units (ECUs), ADAS systems
Aerospace: Satellite PCB mounting, avionics enclosures
Medical Devices: MRI scanner internal structures
Consumer Electronics: Smartphone PCB stacking

6. Leading Manufacturers & Products

Manufacturer	Representative Product
PEM	S-8900 Series self-clinching standoffs
RS Components	486-8826 insulated hexagonal spacers
Mouser Electronics	925206-12 adjustable PCB spacers
McMaster-Carr	91285A102 stainless steel standoffs

7. Selection Recommendations

Evaluate mechanical load requirements vs material strength
Match thread type (UNC/UNF/Metric) with assembly hardware
Consider CTE (Coefficient of Thermal Expansion) compatibility with PCB materials
Select insulated variants for >50V circuits
Use vibration-damping coatings in mobile applications

8. Industry Trends

Emerging developments include:

Miniaturization: Sub-1mm spacers for wearable devices
Material Innovation: Conductive polymer composites for EMI shielding
Smart Integration: Standoffs with embedded strain gauges for structural monitoring
Automated Installation: Self-aligning designs for robotic assembly lines
Sustainability: Biodegradable plastic options (PLA-based) entering mainstream production