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SMEPI, manufacturer of trapezoidal thread screws

The trapezoidal thread screw  is generally used for the transmission of large and precise forces. Very resistant to heat treatments, it is fitted to various machines and mechanical tools: vices, presses, screw presses, screw clamps or even jacks. Expert in machining precision mechanical parts, SMEPI manufactures screws of various shapes, sizes and grades

Trapezoidal thread screw: characteristics and applications

In terms of precision screws, trapezoidal threads are used to make maneuvering screws or screws for transmission of forces, to one or more threads. They differ from triangular fillets by their greater tolerance to heat treatments.

The particular shape of the trapezoidal thread gives it unique advantages. On a conventional screw, the profile of the thread is an equilateral triangle with an angle of 60 °, while on a trapezoidal screw, it is rather an isosceles triangle with an angle of 30 ° truncated and which therefore has a shape trapezoidal, so as to obtain a harder surface, therefore more resistant to wear and with less friction. Another interesting feature of the trapezoidal thread  : as the base of the trapezoid is slightly wider than that of the equivalent triangle and the screw can more easily receive heat treatments, trapezoidal screws have better resistance to stress.


The trapezoidal thread is therefore used for the transmission of large and precise forces. The trapezoidal screw / nut system converts rotational movement into linear movement and vice versa.

Standard NF ISO 2901, which specifies the basic profile and nominal profiles of metric trapezoidal threads, classifies trapezoidal threads into two categories:

  • On the one hand, the profiles with vacuum at the bottom of the thread and without play on the sides, which allow better centering between the screw and the nut or improved concentricity.

  • On the other hand, profiles with vacuum at the bottom of the thread and with clearance on the sides for a more general application.

Generally, trapezoidal threading is used in precision machines (machining center, machine with high feed and rotation speeds, drive systems, etc.), medical equipment, presses, cutting machines. Trapezoidal thread screws represent an affordable solution for clamping, positioning and advanced movement operations.

SMEPI is developing recognized expertise in precision industrial mechanics. We have three specificities which are:  

  • Rolled threading and production of all types of threads,

  • Deep drilling without overturning,

  • Electroerosion and rectification.


Manufacture of threaded screws

Threaded screws are often used in the mechanical engineering industry and in the building industry. We manufacture all types of threaded screws in accordance with all mandatory international standards and in the desired dimensions.

Thanks to our modern machine park, we can respond to most requests at short notice. We also take care of all your finishing operations in order to guarantee you finished and ready-to-use parts: milling, turning, surface treatment. Surface treatment - electro zinc plating, alkaline degreasing, cadmium plating, nickel plating, etc. - consists in adding a coating which will improve the appearance or the physical properties of the screw and thus allow its adaptation to specific conditions of use.

We also manufacture matching trapezoidal nuts and special trapezoidal threads according to your requirements. To order, all you need to do is provide us with the specifications you want.  

A few words about SMEPI

Specialist in precision mechanics, SMEPI manufactures and supplies all wearing and safety parts as well as specific mechanical assemblies or sub-assemblies for the civil nuclear, rail and aeronautical, defense and shipbuilding industries. .

We implement a very demanding quality approach focused on four major axes: documentation and study, traceability, quality control in the service of safety / security, the manufacturing process.


In the very specialized field of precision machining, we have more than 10 years of success to our credit, and we enjoy an excellent reputation all over France. For the machining of your mechanical parts SMEPI is an essential service provider to whom you can contact. SMEPI has all the key resources to assist you through all the stages of your project, from the study to the heat and surface treatment, including: assembly, heat and surface treatment, prototyping, study, machining, selection of materials to use ... and finally, a rigorous control of your parts. Our achievements are suitable for companies with very numerous technological problems, in particular: special machines, energy, transport, chemicals, nuclear, petrochemicals, etc. Our machining company trusts a highly qualified team and has a substantial stock of raw materials in order to meet your quality and speed requirements.

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