Bright Steel / GR
Grinding
Grinding is applied for applications requiring the highest surface quality and tightest tolerances. Excellent dimensional accuracy and mirror-like surface finish is achieved in h7/h8 tolerance classes. Preferred for critical parts such as precision hydraulic cylinders, piston rods, and bearing shafts.
Technical Specifications
Process
Centerless Grinding
Tolerance
h7 / h8 / h9
Size Range
Round: 10-80mm
Standards
EN 10278, EN 10277, ISO 286-2
Key Features
- Tightest tolerance class (h7) - micron-level precision
- Excellent surface quality (Ra ≤ 0.4 µm)
- Mirror-like surface finish
- Straightness ≤ 0.5mm/m
- Ideal surface preparation for chrome plating
- Surface compatible with sealing elements
- Ovality and taper at minimum levels
- High precision dimensional repeatability
- Defect-free production for safety-critical parts
- Applicable on heat-treated or raw material
Applications
- Precision hydraulic cylinder pistons
- Pneumatic cylinder rods
- Chrome-plated piston rods
- Bearing shafts and axle pins
- Linear motion systems (linear shafts)
- Injection molding machine tie bars
- Printing machine shafts
- Medical equipment components
Dimension Table
| Profile | Size Range (mm) | Tolerance | Standard | Surface (Ra) |
|---|---|---|---|---|
| Round | 10 - 20 | h7 | EN 10278 | ≤ 0.4 µm |
| Round | 20 - 30 | h7 | EN 10278 | ≤ 0.4 µm |
| Round | 30 - 50 | h7/h8 | EN 10278 | ≤ 0.6 µm |
| Round | 50 - 65 | h8 | EN 10278 | ≤ 0.8 µm |
| Round | 65 - 80 | h8/h9 | EN 10278 | ≤ 0.8 µm |
Technical Notes
- 01h7 tolerance requires micron-level precision (e.g., Ø30mm: -0/+21µm).
- 02Material must be cold drawn or peeled prior to grinding.
- 03Centerless grinding is economical for high-volume production.
- 04Surface roughness must be Ra ≤ 0.4 µm before chrome plating.
- 05Standard length: 3000-6000mm, max 7000mm production possible.
- 06Machined surface is coated with protective oil against oxidation.
- 07Grinding process also improves straightness tolerance.
Steel Grades
C30C35C40C45C5034CrMo442CrMo4SAE 4140SAE 104516MnCrS520MnCrS511SMnPb3011SMn30S355J2S355J2G351CrV4100Cr6ETG 88ETG 100CK45Ck60
Other Types
Related Blog Posts
Technical articles, guides and industry analyses
Technical
Steel Hardness Testing Methods: HRC, HB, HV Guide
Comprehensive guide to steel hardness testing methods. Comparison of Rockwell (HRC), Brinell (HB), and Vickers (HV) methods, conversion tables, and proper method selection.
3 min
Manufacturing
Hot Rolled vs Cold Drawn: Differences, Advantages, and Selection Criteria
A detailed comparison of hot rolling and cold drawing processes. A guide for selecting the right bar form in terms of surface quality, tolerance, cost, and mechanical properties.
3 min