M4 Screws: Size, Specifications, and Custom Solutions

M4 screws  are essential fasteners in manufacturing, electronics, and machinery, known for their 4mm diameter and versatility. This guide covers M4 screw sizes, specifications, applications, and solutions for common issues like stripped screws. Learn how Shi Shi Tong provides custom M4 screws tailored to your needs.

 

 

What Size Is an M4 Screw?

 

An M4 screw has a nominal diameter of 4mm. Its standard coarse thread pitch is 0.7mm (M4×0.7), ideal for general applications. Fine pitch options (e.g., M4×0.5) are used for precision or vibration-resistant assemblies. Lengths range from 8mm to 20mm or more, depending on material thickness.

Tip: Screw length should be at least 1.5 times the diameter (6mm) plus material thickness. For a 2mm plate, an M4×8 screw is suitable.

 

 

 

What Defines an M4 Screw?

 

M4 screws are metric fasteners with a 4mm major diameter, adhering to ISO standards. Key characteristics include:

• Thread Pitch: Coarse (0.7mm) or fine (0.5mm).
• Head Types: Hex, socket (Allen), Phillips, flat, or countersunk.
• Materials: Stainless steel (A2/A4), carbon steel, brass, or titanium.
• Strength: Carbon steel screws may have grades like 8.8 or 10.9; stainless steel is ungraded but corrosion-resistant.

M4 screws are used in electronics, furniture, and machinery, often paired with M4 nuts (0.7mm pitch).

 

M4 Screw Specifications Table

Feature	Details
Diameter	4mm
Standard Pitch	0.7mm (coarse), 0.5mm (fine)
Length Range	8mm, 16mm, 20mm, or custom
Head Types	Hex, Socket, Phillips, Flat, Countersunk
Driver Tools	4mm wrench, 2.5/3mm hex key, PH1/PH2 screwdriver
Materials	Stainless Steel, Carbon Steel, Brass, Titanium

 

Common Applications for M4 Screws

M4 screws are versatile, used in:

• Electronics: Securing circuit boards or hard drive brackets.
• Machinery: Fastening components in precision equipment.
• Furniture: Assembling frames or fittings.
• 3D Printing: Mounting components in custom builds.

 

 

What Screwdriver for M4 Screws?

 

The screwdriver depends on the head type:

• Phillips: PH1 or PH2 for cross-head screws, common in electronics.
• Hex/Socket: 2.5mm or 3mm hex key for Allen screws.
• Hex Head: 4mm wrench for external hex bolts.

Tip: Use ESD-safe screwdrivers for electronics to prevent static damage. Avoid undersized tools to prevent stripping.

 

 

 

How to Remove Stripped M4 Machine Screws?

 

Stripped M4 screws are a common issue. Try these methods:

• Rubber Band Trick: Place a rubber band over the stripped head and press with a PH2 screwdriver for extra grip.
• Screw Extractor: Use a tool like the IRWIN Bolt Extractor Set to drill and remove the screw.
• Lubrication: Apply WD-40 to rusty screws, wait 10 minutes, then retry.
• Cutting a Slot: Use a Dremel to cut a new slot for a flathead screwdriver.

Safety Note: Wear goggles when using power tools. For precision equipment, consult a professional.

 

 

Case Study: Custom Brass M4 Screws for a German Electronics Manufacturer

In 2024, a German electronics manufacturer approached Shi Shi Tong needing M4×20mm brass screws with a fine pitch (0.5mm) for a high-vibration circuit board application. Standard screws were too short and lacked the required corrosion resistance. Our team:

• Designed screws with precise threading to ensure vibration resistance.
• Used high-grade brass for conductivity and durability.
• Delivered 10,000 units within two weeks, meeting the client’s production deadline.

The client reported a 30% reduction in assembly issues, praising Shi Shi Tong’s rapid customization. 

 

 

 

Why Choose Shi Shi Tong for Custom M4 Screws?

 

Unlike retailers, Shi Shi Tong specializes in non-standard, custom screws for manufacturers. Benefits include:

• Tailored Solutions: Custom lengths (e.g., 20mm M4 screws), materials (e.g., brass), and pitches.
• Quality Assurance: ISO-compliant screws with rigorous testing.
• Fast Turnaround: Prototypes delivered in days, bulk orders in weeks.

 

 

 

FAQ

 

What Size Is an M4 Screw?

An M4 screw has a 4mm diameter and a standard 0.7mm coarse pitch. Lengths vary (e.g., 16mm, 20mm).

What Defines an M4 Screw?

An M4 screw is a metric fastener with a 4mm diameter, available in coarse (0.7mm) or fine (0.5mm) pitch, used in electronics and machinery.

What Screwdriver for M4 Screws?

Use a PH1/PH2 Phillips, 2.5/3mm hex key, or 4mm wrench, depending on the head type.

How to Remove Stripped M4 Screws?

Use a rubber band, screw extractor, or WD-40. For severe cases, cut a new slot with a Dremel.

 

 

 

Need Custom M4 Screws?

For long M4 screws, brass M4 screws, or other non-standard fasteners, contact Shi Shi Tong. Our team delivers tailored solutions for manufacturers worldwide.

 

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