This guide supports Extramet’s tungsten carbide machining services by answering the practical engineering and purchasing questions that usually come before an RFQ.
Quick Answer
- Surface finish affects friction, wear, sealing, sliding, and measurement.
- Polish finish may be useful for low-friction or critical contact surfaces.
- Finish requirements should be stated separately from dimensional tolerance.
| Finish need | Why it matters | RFQ note |
|---|---|---|
| Regular ground | General precision function | Define acceptable appearance or Ra if needed |
| Polish | Reduced friction or smoother contact | Specify contact surface |
| Critical seal | Leakage and wear control | State Ra and inspection method |
Finish is functional
Surface finish is not just cosmetic on carbide. It can affect wear, friction, sliding behavior, sealing, cleaning, and how a part measures against mating components.
Do not bury finish in notes
A drawing should clearly identify which surfaces need which finish. If every surface is marked with a tight finish, grinding cost and inspection time can rise quickly.
Match finish to application
Pins, rods, punches, and wear components may need different finishes depending on contact pressure, speed, material, lubricant, and tolerance.
What to Include in an RFQ
- surfaces requiring finish
- finish value or polish requirement
- application contact conditions
- inspection method
Related Extramet Resources
Reviewed for technical accuracy: This supporting article was prepared to align with Extramet’s tungsten carbide manufacturing, grinding, inspection, and quality capabilities in Latrobe, Pennsylvania.
Frequently Asked Questions
Is polish finish always better?
Not always. It can add cost and may be unnecessary for non-critical surfaces.
Should finish be specified in Ra?
If finish is critical, an Ra value and measurement method are helpful.
Can finish affect wear life?
Yes. Finish can influence friction, heat, material transfer, and wear.