Quick Answer: Choose the Finish After the SDS Architecture
The body finish is not the cutting system. First lock the application, SDS-Plus or SDS-Max platform, carbide head, joining route, body steel, heat treatment and flute. Then choose the finish for the appearance, handling, corrosion-control and packaging requirement.
| Finish direction | Appearance | Engineering role | Typical program fit |
|---|---|---|---|
| Sandblasted / shot-blasted | Uniform matte silver-grey | Removes scale, evens the surface and prepares it for the agreed protection | Professional bulk, tubes, contractor programs |
| Blasted + protective oil / clear protection | Matte steel retained | Adds storage and transit protection to the blasted surface | Export cartons, warehouse stock, humid routes |
| Black oxide + oil | Dark matte finish | Conversion finish with oil retention and product-line identification | Trade ranges and dark private-label programs |
| Nickel plated | Bright silver | Buyer-specified plated appearance and corrosion-control direction | Retail presentation or specified humid-market program |
| Colour lacquer / identification band | Brand colour on defined zones | SKU identification and visual branding, not material upgrading | OEM assortments and set differentiation |
Sandblasting: The Practical Baseline
Sandblasting or shot blasting is a practical SDS body treatment because it cleans oxidation and processing scale and produces a controlled matte texture across complex flutes. It also reduces visible variation between forging, machining, heat-treatment and joining zones before final marking and packaging.
Blasting does not create a sealed corrosion barrier. A bare blasted surface can oxidise if it is packed wet, touched with contaminated gloves or stored through condensation cycles. The full specification therefore states what follows blasting: rust-preventive oil, a clear temporary protector, sealed tube or bag, desiccant where agreed, and the required storage or transit check.
Black Oxide and Nickel Are Options, Not Quality Tiers
Black oxide gives a dark industrial appearance and can hold a protective oil film. Nickel plating gives a bright plated appearance and can be specified with a defined corrosion requirement. Neither automatically makes the drill faster, tougher or more accurate.
Do not use finish colour to infer 40Cr versus 42CrMo, YG8C versus YG11C, brazed inserts versus a full-carbide head, or one heat-treatment route versus another. Those are separate lines on the approved specification. Zhonghuan can review a requested finish direction against the product construction and order volume before sample release.
Where the Finish Sits in the Process
The normal control sequence is body forming and flute machining, heat treatment, straightening and dimensional release, carbide joining, surface cleaning or blasting, the approved finish, marking and protective packaging. The exact order can vary with the selected joining and coating process, so the released process sheet—not a generic colour name—governs production.
Critical fit and identification zones need their own instruction. SDS locking grooves, shank fit surfaces, carbide cutting faces, brazed or welded interfaces, wear marks and laser marking areas may require masking, post-cleaning or a defined final appearance.
How to Approve an OEM Finish
- Choose an appearance master. Approve a physical sample or controlled image for colour, gloss and texture.
- Define the treated zones. State whether the flute, body, shank and head transition receive the same finish.
- Define corrosion control. If a test is needed, state the method, preparation, acceptance condition and duration on the PO.
- Confirm marking. Verify laser contrast, readability and position after the finish is applied.
- Test the packaging system. Oil, clear protector, sleeve, tube, carton and desiccant work as one storage system.
- Release the finished sample. The approved finish sample becomes the visual reference for production and repeat orders.
RFQ Checklist
- SDS-Plus or SDS-Max family and target application
- Body steel and approved heat-treatment route
- Finish direction: blasted, blasted + protector, black oxide, nickel plated or buyer-defined
- Appearance sample, colour/gloss target and treated zones
- Corrosion test requirement, only where the buyer requires one
- Laser marking and packaging format
- Destination, storage route, quantity per SKU and annual volume
Send the machine class, substrate, product architecture and preferred appearance. Zhonghuan will return a body-finish direction and finished-sample plan as part of the project quotation.