Manufacturer of special screws, bolt studs, and special turned parts according to drawings, starting from 1 piece, for pressure equipment and mechanical engineering.
Adolf Schmidt GmbH
Freudenberg-Alchen (Headquarters with administration and production)New on Amplifa
Special Screws from the Siegerland – Since 1948
Adolf Schmidt GmbH (ASO Schrauben) is a manufacturer of special screws, bolt studs, and special turned parts founded in 1948 in Freudenberg-Alchen in the Siegerland region. The company manufactures hexagon screws (M6–M120), bolt studs with full and socket threads according to DIN 2509/2510, pin screws, eye screws, tapped screws, as well as special screws and nuts according to drawings – according to DIN, EN, ISO, or ANSI, starting from 1 piece. The value creation includes CNC turning and milling, thread rolling up to M120 (rolling force 100 t), nitriding, and proprietary surface coatings such as electroplated zinc, zinc-nickel, phosphating, nickel plating, and Xylan. Heat-treated, heat-resistant, superheat-resistant, cold-tough, rust-proof, and acid-resistant steels and duplex steels are processed from certified EU raw material. A focus is placed on connection elements for pressure equipment construction (pressure vessels, heat exchangers, valves, steam systems) as well as for turbine, mechanical, plant, and steel construction. In 2026, the machine park was expanded with a 5-axis turning machine (turning diameter 420 mm, turning length approx. 3100 mm, connection elements up to M180) and a PROFIROLL roll machine.
- Site
- Freudenberg-Alchen
- Processes
- Turning special screws and special turned parts (CNC turning machines, turning and milling, Milling (Turning and milling technology), Thread rolling (Forming process, non-cutting deformation), Manufacturing of threads up to M120, Electroplated zinc with passivation (e.g., blue, yellow), Electroplated zinc with thick film passivation, Zinc-nickel coating, Phosphating
- Materials
- C35E, X22CrMoV121, X12Ni5, 25CrMo4, 42CrMo4, 21CrMoV57, X5CrNi1810, X2CrNiMo17122
- Certificates
- ISO 9001:2015, PED 2014/68/EU (Module 4.3, QS System), AD 2000 Notice W0, IATF 16949, EN 9100, ISO 13485
- Founded
- 1948
- Industries
- Pressure equipment construction, Mechanical engineering, Plant construction, Turbine construction, Steel construction, Energy technology (pressure vessels, heat exchangers, valves, steam systems)
- 01
Material procurement (certified EU raw material with certificate)
- 02
CNC turning and milling
- 03
Thread rolling (non-cutting deformation)
- 04
Heat treatment/Nitriding
- 05
Surface coating
- 06
Quality inspection with factory and test certificates
- 07
Shipping/Express service
Locations
Freudenberg-Alchen
DEHeadquarters with administration and production
- Lot size
- from 1 piece to series
- Materials
- Heat-treated, heat-resistant, superheat-resistant, cold-tough and non-rust bearing steels, Duplex
- 5-axis turning machine (Ø 420 mm, turning length approx. 3100 mm, up to M180, servo-driven chuck, glass scales)
- PROFIROLL roll machine (Rolling force 100 t, threads up to M120)
- CNC turning machines with driven tools (Fanuc control)
- Coating system (electroplated surface technology)
Components
Inside the production
Industries
Processes & technical limits
| Processes | Tolerance | Max. part | Weight | Lot size | Materials |
|---|---|---|---|---|---|
| Turning special screws and special turned parts (CNC turning machines, turning and millingMachining | – | – | – | 1 piece | C35E (1.1181), X22CrMoV121 (1.4923), X12Ni5 (1.5680), 25CrMo4 (1.7218), 42CrMo4 (1.7225), 21CrMoV57 (1.7709), X5CrNi1810 (1.4301), X2CrNiMo17122 (1.4404), X6CrNiMoTi18102 (1.4541), X6CrNiMoTi17122 (1.4571), X5NiCrTi2615 (1.4980), X7CrNiMoBNb1616 (1.4986) |
| Milling (Turning and milling technology)Machining | – | – | – | – | – |
| Thread rolling (Forming process, non-cutting deformation)Forming | – | – | – | – | unalloyed and alloyed steels, Heat-treated steels, Stainless steels |
| Manufacturing of threads up to M120Forming | – | – | – | – | – |
| Electroplated zinc with passivation (e.g., blue, yellow)Surface | – | – | – | – | – |
| Electroplated zinc with thick film passivationSurface | – | – | – | – | – |
| Zinc-nickel coatingSurface | – | – | – | – | – |
| PhosphatingSurface | – | – | – | – | – |
| Electroplated nickel plating / Nickel platingSurface | – | – | – | – | – |
| Xylan coatingSurface | – | – | – | – | – |
| Browning (Bluing)Surface | – | – | – | – | – |
| Nitriding (Nitrocarburizing)Heat treatment | – | – | – | – | – |
| Copper platingSurface | – | – | – | – | – |
| DescalingSurface | – | – | – | – | – |
| Manufacturing of bolt studs with full and socket threads (DIN 2509 / DIN 2510)Machining | – | – | – | 1 piece | plain/zinc plated steel, Stainless steel A2 (V2A), Stainless steel A4 (V4A), heat-resistant steels, Duplex steels |
| Manufacturing of hexagon screws (DIN 933/931, ISO 4014/4017, DIN 960/961, M6–M120)Machining | – | – | – | 1 piece | plain/zinc plated steel, Stainless steel A2 (V2A), Stainless steel A4 (V4A), heat-resistant steels, Duplex steels |
| Manufacturing of fasteners up to M180 (Turning large parts, max turning diameter 420 mm, max.Machining | – | 3100 mm × 420 mm (turning diameter) | – | – | – |
3 Anlagen & Maschinen
| Machine | Manufacturer / model | Quantity | Working area | Year built | Site |
|---|---|---|---|---|---|
| 5-axis turning machine | – | 1 | max. turning diameter 420 mm, max. turning length approx. 3100 mm; servo-driven chuck, glass scales | – | Freudenberg-Alchen |
| Thread rolling machine (roll machine for large parts) | PROFIROLL | 1 | Rolling force 100 tons, threads up to M120 | – | Freudenberg-Alchen |
| CNC turning machines | – | – | – | – | Freudenberg-Alchen |
Additional services
Quality and Certification
The management system is certified according to DIN EN ISO 9001:2015 (TÜV NORD, initial certification 2005); the production meets the requirements of the Pressure Equipment Directive 2014/68/EU (Quality System Module 4.3) and AD 2000 Notice W0. Upon request, Adolf Schmidt GmbH provides factory certificates, material test certificates 3.1/3.2 according to EN 10204, and acceptance tests, based on certified EU raw material with certificate documentation.
| Evidence | Freudenberg-Alchen |
|---|---|
| ISO 9001:2015 | |
| PED 2014/68/EU (Module 4.3, QS System) | |
| AD 2000 Notice W0 | |
| IATF 16949 | |
| EN 9100 | |
| ISO 13485 |
History
- 1948
Found founding of the Adolf Schmidt company; since then the company has stood for craftsmanship quality and precision products in the Siegerland.
- 2005
Initial certification of the management system according to DIN EN ISO 9001 by TÜV NORD CERT GmbH.
- 2026
Expansion of the machine park: new 5-axis turning machine (max turning diameter 420 mm, turning length approx. 3100 mm, fasteners up to M180) and PROFIROLL roll machine (100 t rolling force, threads up to M120).