SCHAAF - NEWS December 2014

The company
Since its foundation in 1977, SCHAAF stands for design and manufacturing of high-quality and superior hydraulic high-pressure tools for special applications.
In order to offer the customer tensioning tools and media for any imaginable situation and state, SCHAAF expanded the product range with mechanical multiple screw and tenisioning elements in 2012. These tensioning elements with the name „Multiple Stud Nut“, shortly MSN, are available in the catalogue options standard (MSN-ST) and in the High-Strength-Design (MSN-HS). Of course, customised solutions (MSN-CS) can also be produced and purchased at SCHAAF. Further information and versatile fields of application can be found under under the menu item MSN. In order to test the quality and the competitive capability, you can also find an inquiry form for a direct and cost-free inquiry for MSN.

References for Multiple Stud Nuts are available in many technical fields. As an example of a hig-end application of MSN, there is the offshore converter platform „HelWin Alpha“ of network operator TenneT in co-operation with Siemens AG, which is shown in the following images.

Total view of „HelWin Alpha“ in front of Helgoland MSN-CS/M160x6

Total view of „HelWin Alpha“ in front of Helgoland


The platform with a total weight of 12,000 tonnes is tensioned and fixed at six pillars with 36 MSN. The MSN with an outer diameter of 320 mm and 16 pressure bolts M30x2 perform a max. tensioning force of 8000 kN with an initiating tensioning moment of 2400 Nm per pressure bolt. Tensioning is therefore achieved with an electrical torque screwdriver with a special bolting method developed by SCHAAF. The quality and application of the product satisfied so well, that for a second platform „BorWin Beta“ Multiple Stud Nuts of SCHAAF were used again as tensioning elements.
In order to complete the scope of delivery, the necessary assembly tools were supplied by SCHAAF as well. This included besides MSN themselves also stud-bolts and the required tools for handling and tensioning like torque wrenches and so on. For protecting the MSN in use from outside influences, either synthetical or stainless steel protection caps can be offered and supplied. Due to these two successful projects, SCHAAF is now also supplier for the third installed platform.

Own engineering
The general requirements to MSN as a machine element for enduring and safe tensioning is very high. This applies to both standard series and special solutions which are developed according to customer specifications. Engineering is therefore handled by SCHAAF and thus can be realised purposeful and quick.

In-house manufacture
Manufacturing is nearly completely done by SCHAAF in order to offer solutions even in short terms. With the investment of 1.5 million euros in a new turning and milling center and in an assembly area for MSN, the quality of MSN is raised to a maximum and, additionally, manufacturing costs are lowered. These savings of costs are forwarded with convenient MSN prices to you.

Catalogue MSN of standard (ST) and high-strength (HS) design

Catalogue MSN of standard (ST) and high-strength (HS) design

Quality assurance
To assure quality, pressure bolts undergo a pressure-force-check at random during manufacture. This way it can be assured, that characteristics and material requirements are met.
Furthermore, the mounted MSN is checked on the existing own test benches prior to delivery. With a load measuring ring the initiated tensioning force into the main bolt, in dependance of the tensioning moment can be measured and recorded. Thus, the user knows the tensioning moment which achieves the necessary pretensiong force under guarantee. Calculated tensioning moments are verified this way, which become an additional quality advance. The tensioning results are controlled by construction and quality assurance and the MSN are then released for packing and shipping.
In addition to this high quality standard, SCHAAF offers to test any component with concluding certification. The material used by SCHAAF is by default certified with 3.1 material certification according to EN ISO 10204, which can be provided as needed. If additionally checks after other or differing norms or tests of the finish part are wished, e. g. ferromagnetic powder check or hardness test, it is executed according to instructions of the customer. If a 3.2 certification by a third independent party is necessary, this can be offered, of course.

MSN are packed into a protective film and are thus protected from dust and any kind of corrosion. Furthermore, this packaging prevents contamination of the used lubricant with dust, which guarantees the functionality of the MSN even after long-term storage. Thus, MSN is 100 % operational at all time.

Due to the optional worldwide SCHAAF assembly support (also offshore), the additional value of the product is ensured. SCHAAF is looking forward to convincing and supporting your future products with the quality of the product MSN – test it yourself!!