T-BOLT head screw, M8x25 28/15 A2

Aluminium rails have a channel on their upper face, like a curtain rail. This screw has a rectangular head: you insert it into the channel, turn it a quarter turn and it locks there, like a latch. That is why it is called a hammer head screw. On it are fastened the clamps that hold the panels and the other accessories of the structure.

The practical advantage is that you can install and move the parts anywhere along the length of the rail, without inserting them at the end of the profile, so a position can be corrected even after the structure is partially assembled. It is usually tightened to 15-20 Nm, in accordance with the indications of the structure manufacturer, together with the corresponding nut and spring washer. One piece weighs 0.015 kg, and the standard packaging has 100 pieces. Being of stainless steel, it does not rust and remains removable even after years of exposure, when a panel might need to be taken out.

Corab code M546, EAN 4043377228901, M8 thread, length 25 mm, head 28x15 mm dimensioned for the T-type channel of Corab rails, A2 stainless steel (1.4301), equivalent AISI 304, weight 0.015 kg/pc, packaging 100 pcs. Austenitic stainless steel and aluminium form a weak galvanic couple, without significant corrosion under normal conditions of exposure. Installation by inserting the head into the channel and turning it by 90 degrees, with usual tightening of 15-20 Nm. Intended exclusively for use as a connecting element in support structures for photovoltaic modules.

Who it suits

Suitable for the installer or for whoever completes an existing system and needs channel screws for clamps, connectors and brackets.

Terms explained

• T-type channel: The groove on the face of the aluminium rail, into which the head of the screw enters and along which it can move freely.
• Hammer head (T-bolt): A rectangular head that locks in the channel after a 90-degree turn, without access to the end of the profile.
• A2 stainless steel (1.4301): Common stainless steel for outdoor use, equivalent AISI 304, compatible with aluminium parts.

Technical specifications

Recommended applications

• Fixing mid and end clamps on aluminium rails
• Fastening connectors and brackets in the T channel of the profiles
• Installation and repositioning on the rail without access to the end of the profile
• Joints exposed outdoors, which require stainless steel

Technical details

Specifications confirmed from the manufacturer's datasheet

The hammer head screw (T-bolt, hammer head) Corab M546 is the connecting element between the aluminium profiles and the accessories of the mounting system. It has an M8 thread, a length of 25 mm and a rectangular head of 28x15 mm, dimensioned for the T-type channel of Corab mounting rails. The EAN code is 4043377228901, the net weight is 0.015 kg per piece, and the standard packaging contains 100 pieces.

The material is A2 stainless steel (1.4301), equivalent AISI 304, a mandatory choice for connecting elements permanently exposed to the weather and in direct contact with the aluminium of the profiles: austenitic stainless steel and aluminium form a weak galvanic couple, which does not generate significant corrosion under normal conditions of exposure.

Installation is done by inserting the head into the T channel of the rail, followed by a 90-degree turn, which locks the head in the channel without access to the end of the profile. This allows the free positioning and repositioning of clamps, connectors and brackets along the rail, including after the structure is partially assembled. Tightening is usually done at a torque of the order of 15-20 Nm, in accordance with the indications of the structure manufacturer.

The screw is used together with the corresponding nut and spring washer and is intended exclusively for use as part of support structures for photovoltaic modules.