M4 x 55mm Socket Cap Head Screw, Self Colour, Grade 12.9 high tensile steel, DIN 912

M4 Cap Head Screw

M4 cap head screw with a deep internal socket drive allowing easy installation, loosening, and the application of torque for a secure hold.

With a compact cylindrical head that’s ideal when space is tight and combined with a deep socket recess allows torque to be applied easily with an Allen key making them a popular choice.

A self-colour machine screw manufactured in grade 12.9 high tensile steel for reliability and in accordance with DIN 912 standards. 

Often referred to as cap head bolts in the trade but also known as an Allen key bolt or socket screw.

Available in a large number of sizes and lengths, these cap head screws are widely used across many diverse sectors including automotive, aerospace, machinery, and construction.

M4 socket cap head screw specification:

• Diameter (TD): M4 x 4mm
• Length (L): 55mm
• Thread length (TL): 20mm min
• Head width (HW): 7mm max
• Head height (HH): 4mm max
• Head type: Cap Head
• Recess type (DT): Internal hex drive (Size 3mm)
• Pitch: 0.70mm
• Material: Grade 12.9 high tensile steel
• Conformity: DIN 912

A self-colour socket cap head screw part of an extensive range available from Fusion Fixings.

FAQs about self-colour cap head socket screws

What does “Grade 12.9” mean with socket cap head screw?

Grade 12.9 refers to a high-tensile steel strength class. It means the screw has an ultimate tensile strength of 1200 MPa (or approximately 175,000 psi) making it one of the strongest metric fasteners available.

Grade 12.9 is typically used in engineering, automotive, machinery and heavy-duty applications where maximum strength is required.

What is a “self-colour” finish?

“Self-colour” means the screw is supplied in its natural steel finish after heat treatment. The screws are sometimes lightly oiled or treated with a black oxide.

Are grade 12.9 socket cap screws corrosion-resistant?

No, these cap head screws are not corrosion resistant and the self-colour or black oxide finish gives limited resistance, making them not suitable for external conditions.

How is the length of the cap head screw measured?

The length of these screws is measured from under the head to the end of the thread, not including the head height.

Can I use grade 12.9 screws in high-temperature or vibrating applications?

Yes, these grade 12.9 screws are suitable for high operating temperatures and perform well in vibration-prone environments such as engines or machinery where they are widely used.

Why choose Fusion Fixings?

A family run business with over 40 years of experience in the construction and fixings industry. Our aim is to bring you a range of quality, reliable, fixings and fasteners at great prices.

With quantities starting from just one to as many as you like, with bulk price offers across many of our products.