Custom Bolts to Drawing

When standard fastening components do not meet the requirements of the project, the solution is made-to-drawing fasteners. Non-conventional dimensions, dedicated geometries, special materials or particular performance requirements require customized production, developed starting from the customer’s technical specifications.

EFS coordinates the production of made-to-drawing fasteners by selecting qualified Italian and European manufacturers and managing the entire process, from project review through to delivery of the finished component. The objective is not simply to produce a mechanical part, but to ensure that each component meets the dimensional, mechanical and documentation requirements of the application.

Made-to-drawing production becomes necessary when ISO, DIN, UNI or ASTM standards do not provide a component with the required characteristics, or when a standard solution is not compatible with the project.

The most frequent requests concern special lengths, non-standard diameters, dedicated thread pitches, customized geometries, particular materials or specific treatments. In other cases, an existing component must be reproduced, maintaining full interchangeability with the original part or adapting it to new project requirements.

Each supply therefore originates from a specific application need and is developed according to the actual operating conditions.

The production of a special fastening component requires the coordination of different technical and manufacturing skills.

The process begins with the analysis of the technical drawing or sample provided by the customer, checking geometries, tolerances, threads, materials and functional requirements. The most suitable production process, heat and surface treatments, machining operations and any required inspections are then identified.

During production, each stage is monitored to ensure compliance with the project specifications and repeatability of supplies, aspects that are essential especially in continuous procurement programmes.

Made-to-drawing production does not concern a single product family, but a wide range of fastening components intended for many different industrial sectors.

The most commonly requested components include:

• special screws;
• special nuts;
• stud bolts and threaded studs;
• pins;
• dowel pins;
• set screws;
• threaded plugs;
• special washers;
• other mechanical fastening parts manufactured to specification.

Each component can be developed according to the customer’s drawing or through reverse engineering activities when only a sample is available.

Material selection is one of the most important aspects in the design of made-to-drawing fasteners. Depending on the application, EFS coordinates supplies in carbon steels, alloy steels, stainless steels, Duplex, Super Duplex, ASTM B7 and B16, Inconel and other special alloys.

Material characteristics are combined with machining operations such as turning, milling, grinding, thread rolling, drilling, laser marking and dimensional reworking. The process is completed by heat and surface treatments, selected to ensure mechanical strength, corrosion protection and long-term durability.

In made-to-drawing production, component conformity does not depend solely on machining, but on the entire order control system.

On request, EFS can provide EN 10204 3.1 and 3.2 certificates, dimensional inspections, mechanical testing, destructive and non-destructive testing, as well as full traceability of the raw material and the machining operations performed. This approach makes it possible to meet the documentation requirements of the most regulated sectors and highly critical applications.

The production of made-to-drawing fasteners requires much more than simple manufacturing capability. Materials, machining operations, treatments, inspections and technical documentation must be coordinated so that each component meets the project specifications and can be replicated over time with the same quality.

Thanks to a consolidated network of specialized European manufacturers, EFS manages supplies for OEMs, machine builders, plant engineering companies and maintenance operators, following every stage of the order and ensuring production continuity even for highly customized components.

Yes. When the technical drawing is not available, the component can be developed through reverse engineering activities, checking its geometries, materials and functional characteristics before production.

In addition to screws, nuts, stud bolts and threaded studs, pins, dowel pins, set screws, threaded plugs, washers and other fastening components designed according to customer specifications can be manufactured.

Yes. Supplies can be manufactured in special materials and accompanied by EN 10204 3.1 or 3.2 certificates, dimensional inspections and technical documentation according to the needs of the application.