PROCESSING SPECIFICATION
Sizes, Grades and Checks for Precision Grinding
What we run today, and what we check on every lot.
| Scope | Typical range / requirement | Output | Checks / records |
|---|---|---|---|
| Input size | Round bar with grinding allowance | Ground bar Ø 8–160 mm | Diameter · straightness |
| Grades | C45 · 16MnCr5 · 42CrMo4 · EN24 · 100Cr6 | Ground bright finish | Grade · hardness as specified |
| Control | IT9–IT6 · Ra 0.8–0.4 μm benchmarks | Size and finish to order | Diameter · roundness · roughness |
How We Do It
Round bar, drawn or peeled, with a grinding allowance.
Precision Grinding
Ground bar at IT9–IT6, Ra 0.8–0.4 μm, straight and round.
- Start from a drawn or peeled bar with enough allowance to grind.
- Centreless grind. The wheel brings the bar to the target diameter in one or more passes.
- Check diameter, roundness, straightness and roughness.
- Cut to length, protect the surface and certify the heat.
Why Use Precision Grinding?
A ground bar is the tightest finish we supply. You can often use it straight from the bar with no turning, which cuts a machining step and keeps the diameter consistent from bar to bar.
When Should You Choose It?
Choose ground bar when drawn h9 is not tight enough, or when the bar becomes a shaft, pin or spindle with little further machining. Drawn bar costs less and suits most parts. Peeled bar is the choice when the skin must go and h11 is enough.
Common Questions
What is centreless grinding?
Centreless grinding finishes a round bar between a grinding wheel and a regulating wheel, with no centres holding it. It brings the bar to a precise diameter with a fine, round surface.
How does centreless grinding work?
The bar rests on a support blade between two wheels. The grinding wheel cuts the surface. The regulating wheel turns the bar and feeds it through. The gap between the wheels sets the diameter.
What is centreless grinding used for?
It is used for shafts, pins, spindles, hydraulic rods and any round part that needs a tight diameter and a fine surface straight from the bar.
What is the difference between a bright bar and a ground bar?
A ground bar is one type of bright bar. Drawn and peeled bright bars hold h9–h11. A ground bar is finished last with a wheel and holds IT9–IT6.
What is h9 tolerance on a round bar?
h9 means the diameter can be at nominal size or smaller, down to a limit that depends on size. For a Ø 20 mm bar, h9 is 0 to −0.052 mm. h11 is 0 to −0.130 mm.
How tight can you grind?
OneKaizen grinds to IT9 through IT6. For a Ø 20 mm bar, IT6 is 0.013 mm. Surface roughness benchmarks are Ra 0.8 to 0.4 μm.
What sizes and grades can you grind?
OneKaizen grinds round bar from Ø 8 to 160 mm in C45, 16MnCr5, 42CrMo4, EN24 and 100Cr6, among others.
What do I send for a quote?
Send us the grade, diameter and tolerance, length, roughness and quantity. We come back with the route, inspection plan and delivery date.