Allen head screw M8X20 / piece

This is the classic screw with a cylindrical head and a hexagonal hole in the middle, which is tightened with an Allen key. Its head is low, so it does not catch on the panel frame and does not get in the way during installation. It is used everywhere two parts of the structure have to be clamped to each other.

The 20 mm length is suitable for joints of reduced thickness, typically a clamp on a rail or a connector between two profiles, so it is the part you turn to when you complete an existing system or replace a screw. It is tightened with an Allen key or with a bit on the screwdriver, including in the narrow spaces under the module, where an open-end wrench would not fit. It is used together with a square nut or click nut from the rail channel and with a DIN 7980 spring washer, which prevents loosening over time. Being of stainless steel, it does not rust and does not stain the surrounding aluminium.

Corab code M485, screw with cylindrical head and internal hexagonal socket in accordance with DIN 912 (equivalent ISO 4762), M8 thread, length 20 mm, A2 stainless steel (equivalent AISI 304), sales unit piece. Correct galvanic compatibility with aluminium profiles and clamps. Intended for use as a connecting element in support structures for photovoltaic modules, not as an independent construction element.

Who it suits

Suitable for occasional additions and replacements in an already installed mounting system, when you need a single screw, not a box.

Terms explained

• DIN 912: The standard that describes the screw with a cylindrical head and hexagonal socket, the one tightened with an Allen key.
• Spring washer: An elastic washer, cut obliquely, which keeps the screw tight and prevents it from loosening due to vibrations.
• Click nut: The nut that fixes itself in the rail channel and stays in position, so that it does not have to be held by hand during tightening.

Technical specifications

Recommended applications

• Tightening mid and end clamps on aluminium rails
• Joints between profiles and rail connectors
• Fixings under the module, where a low-profile head is required
• Replacements and additions of connecting elements in existing systems

Technical details

Specifications confirmed from the manufacturer's datasheet

The M8x20 Allen head screw is a screw with a cylindrical head and internal hexagonal socket, in accordance with the DIN 912 standard (equivalent ISO 4762), made of A2 stainless steel. In the Corab catalogue it is listed with the code M485 and is sold by the piece.

DIN 912 is the standard form used in photovoltaic mounting systems because the low profile of the cylindrical head does not interfere with the module frame and does not create snagging points, while the hexagonal socket allows tightening with an Allen key or with a bit on the screwdriver, including in narrow spaces under the module.

A2 stainless steel (equivalent AISI 304) ensures corrosion resistance throughout the service life of the installation and correct galvanic compatibility with aluminium profiles and clamps. The 20 mm length is suitable for joints of reduced thickness, typically a clamp on the rail or a profile connector, in combination with the square nut or click nut from the rail channel and with the DIN 7980 spring washer.

The product is intended for use as a connecting element in support structures for photovoltaic modules, not as an independent construction element.