Allen keys 5×40 aisi 316 – code: a4-7991-05×040 – Osculati

5×40 hex socket screws in AISI 316 stainless steel Osculati (countersunk head, hex socket)

This hex socket screw 5×40 in AISI 316 stainless steel signed Osculati it is designed for technical assemblies where a countersunk head flush surface and practical tightening via hex socket. It is a typical hardware solution used in nautical and plant engineering fields, useful both for new installations and for maintenance and replacement interventions, when it is important to maintain consistency of type and material with the existing bolts.

The product is identified by the supplier code a4-7991-05×040 (SKU oscu000001433) and is associated with the family of countersunk head screws with hex socket according to references UNI 5933 / DIN 7991.

Features and construction details

The combination of countersunk head and internal hex socket makes this screw suitable for contexts where an orderly fastening is required, with reduced surface bulk and the possibility to work with a hex key. The use of AISI 316 places it among common choices for applications where stainless steel bolting is preferred in the nautical field.

Main elements

• Type: hex socket screw with countersunk head and hex socket
• Size: 5×40
• Material: AISI 316 stainless steel
• Family references: UNI 5933 / DIN 7991
• Supplier: Osculati S.r.l.
• Supplier product code: a4-7991-05×040

Countersunk head: when it is useful

The countersunk head it is indicated when the project or component requires a countersunk seat and it is desired that the screw is on thread flush or with minimal protrusion. This approach is common on panels, plates, accessories, and components where the surface must remain free of obstacles, for example for reasons of passage, sliding, aesthetics, or safety of use.

Hex socket: practical tightening in technical spaces

The hex socket socket allows tightening with a hex key, a solution often chosen in technical fields because it allows orderly and controllable tightening action, even when lateral access is limited. It is particularly useful in installations where it is preferred to avoid protruding external heads.

Typical applications (nautical and plant engineering)

This hex socket screw is designed to be part of the standard equipment of hardware for installations and maintenance. In nautical and plant engineering fields, it is commonly used for fastening on components and accessories that require a flush head and stainless steel bolting consistent with the usage environment.

Examples of use

• Technical assemblies on brackets, plates, and supports with countersunk seat
• Accessory installations where a flush surface finish is desired
• Maintenance and spare parts replacement maintaining type and material compatible with existing bolting
• Onboard systems and hardware applications in nautical contexts

Usage and notes for selection

To achieve a correct assembly, it is important to verify that the component to be fixed provides a countersunk seat suitable for the screw head and that the length 5×40 is consistent with the thickness of the materials and with the possible presence of washers or other coupling elements (if provided by your assembly). In case of replacement, it is good practice to compare the existing screw with the new one, ensuring that the type (countersunk head, hex socket) and material (AISI 316) are the desired ones.

Practical advice

• Seat check: the countersunk head works correctly only on a suitable countersink
• Tool: use a hex key in good condition to preserve the imprint
• Material consistency: in maintenance, keeping the same material as the existing fasteners helps to standardize the assembly
• Product identification: for quick reorder refer to the code a4-7991-05×040

Note on standards and references

The reference to UNI 5933 / DIN 7991 is reported as a family indication for the type “countersunk head with hex socket”. In case of specific design requirements, it is advisable to check the requirements of your technical drawing or bill of materials.

FAQ – Frequently Asked Questions

What is the Osculati product code for this hex socket screw?

The supplier product code is a4-7991-05×040. For internal management and reorder you can also use the SKU oscu000001433.

What type of head does this screw have?

It is a hex socket screw with countersunk head, designed to work on countersunk seats and be flush with the surface.

What material is it made of?

The screw is made of AISI 316 stainless steel, a common choice for hardware in nautical and plant engineering fields.

To which reference standards is it associated?

It is indicated in the family of countersunk head screws with hex socket with reference UNI 5933 / DIN 7991.

In which contexts is it typically used?

It is suitable for technical assemblies and hardware work in nautical and plant engineering, both in new installations and in maintenance and spare parts replacement.