Fastening Technology
Modern machinery facility
Material portfolio
Service
Robert Grass – Global
Thanks to our powerful, international company network, we can also offer a very extensive portfolio of fastening elements at attractive conditions from one source with customized logistics solutions.
Nuts
Robert Grass manufactures special and standard nuts with the highest precision, available in round, square, hexagonal, octagonal, and dodecagonal designs, in sizes ranging from M4 to M180 mm.
Upon request, nuts can be individually heat-treated and surface-coated according to customer specifications.
All products are typically marked with our manufacturer’s code “RG”, the strength class, and a traceability number.
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Versions / Configurations
- Round, square, hexagonal, and octagonal cross-sections
- Made from hot-pressed blanks and flame-cut parts
- From rolled, forged, and drawn bar steels
- Supplied natural hard, annealed, quenched and tempered in open or protective gas atmosphere
- Load-bearing surfaces inductively hardened and ground
- Surface finishes such as electroplated zinc, hot-dip galvanized, zinc spray-coated, phosphated, PTFE-coated, zinc flake-coated, and nitrided
- Short- and long-term corrosion protection
- Transport protection using mesh sleeves (on request)
Threads
- Standard and fine metric threads ISO DIN 13, tolerance medium (m) = 6H, fine (f) = 5H
- Round, trapezoidal, pipe, and Whitworth threads
- Unified and National threads UNC – UNF (U.S. standards)
Grades
- According to DIN 267: strength classes 5 – 6 – 8 – 10 – 12
- According to ISO 898-2 up to strength class 12
- According to ASTM A193 / A194
- From free-cutting steels
- From quenched and tempered steels according to DIN EN 10083 (particularly 34CrNiMo6, 30CrNiMo8, etc.)
- From heat-resistant, high-temperature, and age-resistant steels
- From stainless and acid-resistant steels
- From brass and bronze
- From boiler and precision tubes
Marking
Products are permanently marked using machine stamping:
RG = Manufacturer
+ Strength class
+ Batch traceability code
+ Special markings according to customer specification
Bolts
Our product range covers diameters from 6 mm to 650 mm, available in various designs – hot-formed, cold-formed, or machined.
Screws
We manufacture screws according to customer drawings or standards, for both single-item and series production. Strength classes range from 4.6 to 12.9, or as agreed.
Available dimensions: M4 to M72; other diameters upon request.
Washers, Bushings, Spacers
We offer components according to standards, drawings, or samples – in a wide variety of dimensions, tolerances, and materials.
Turned and Milled Parts
Our capabilities include the machining of parts with simple or complex geometries, with diameters from 10 mm to 80 mm from bar stock, as well as chuck parts up to 350 mm in diameter and 650 mm in length. Examples include custom washers with chamfers or special tolerances, as well as spacers.
