Custom 6061-T6 Aluminum CNC Turned Parts with Knurling and Red Anodizing

This 6061-T6 aluminum CNC turned part is made to customer drawings for a consumer product supplied to the US market. At approximately 150 × 45 mm, it combines a stepped turned profile, external thread, large thin flange and a prominent diamond-knurled section.
The production quantity is around 3,000 pieces, with critical dimensions controlled to approximately ±0.05 mm. After machining, the parts are sandblasted and red anodized.
Because this is visible consumer hardware, dimensional accuracy is only part of the requirement. The flange, knurl and anodized surfaces also need a consistent appearance across the production batch.
The complete production cycle—from CNC turning through surface finishing and inspection—can be completed in approximately 15 days.
 

Project Details

A CNC Turned Part That Stays Visible

Most of the geometry is rotational, so CNC lathe machining is the natural production method.
Along the approximately 150 mm profile, the diameter changes several times. One end includes an external thread, followed by a smaller cylindrical section and a large thin flange. The center area carries a diamond knurl, with additional stepped diameters continuing toward the opposite end.
Typical operations include OD turning, facing, shoulder machining, external threading, grooving and knurling.
None of these features is particularly unusual on its own. The difference is that this component remains visible after assembly.
A machining mark on hidden internal hardware may have little consequence. On this part, the broad flange and red anodized surfaces make scratches, dents and uneven texture much easier to notice.
For this reason, surface protection starts during machining and continues through finishing, inspection and packing.
 

The Diamond Knurl Is Part of the Appearance

The knurled center section is one of the most distinctive features in the design.
Its width and position follow the customer's drawing, while the diamond pattern needs to remain consistent through the production run. Damaged peaks, irregular texture or handling marks can still be noticeable after the part has been sandblasted and anodized.
That makes CNC turning and knurling more than a functional machining operation on this project.
The knurl is part of what the end user sees and touches.
For a 3,000-piece run, repeatability in this area matters just as much as producing a good first sample.
 

Machining Quality Carries Through to Anodizing

The specified material is 6061-T6 aluminum, and the parts receive a red anodized finish after machining.
What matters here is the connection between the two processes.
Anodizing does not hide poor part handling. Tool marks, burrs, scratches or surface damage can carry through the finishing process and remain visible on the completed component.
Our production route therefore treats machining and finishing as one continuous job:
CNC Turning → Threading → Knurling → Deburring → Sandblasting → Red Anodizing → Appearance Inspection → Dimensional Inspection
Sandblasting creates the required matte texture before anodizing. The parts then move into the red anodizing process without losing sight of the cosmetic surfaces established earlier in production.
 

One Red Sample Is Easy. 3,000 Parts Need Consistency.

Colored anodizing introduces a challenge that dimensional inspection alone cannot solve.
A single approved sample may look excellent. The real production requirement is keeping approximately 3,000 finished parts visually acceptable when they are used across the same consumer product line.
The large flange makes differences particularly easy to see. Its broad surface leaves little room for scratches, uneven blasting or obvious shade variation to disappear.
Appearance inspection therefore considers:

• Anodized color consistency
• Sandblasted texture
• Scratches and dents
• Handling marks
• Knurled surface condition
• Other visible defects

Colored anodizing naturally has some process variation, so the practical target is not an unrealistic promise that every part will look optically identical under every lighting condition.
The goal is a controlled and consistent batch appearance against the approved requirement.
 

±0.05 mm Where the Drawing Requires It

Critical dimensions on this component are controlled to approximately ±0.05 mm.
That does not mean every dimension needs the same tolerance.
The customer drawing identifies the features that affect fit and assembly—a mating diameter, shoulder position, thread or another functional dimension. Those features receive the appropriate machining and inspection control.
For batch CNC turning, this approach is more useful than unnecessarily tightening every dimension. It keeps the process focused on repeatability where the product actually needs it.
 

15 Days Covers Machining and Surface Finishing

The approximately 15-day lead time covers the complete production route, not just CNC machine time.
That includes turning, threading, knurling, deburring, sandblasting, red anodizing and final inspection.
For a procurement engineer, this is an important distinction. The relevant question is usually not:

“When will CNC machining be finished?”
It is:

“When will my finished parts be ready?”
By coordinating machining and surface treatment within the same production schedule, the lead time reflects finished components prepared for shipment.
 

Precision CNC Turning Services for Aluminum Parts

YS Precision provides precision CNC turning services for components manufactured according to customer 2D drawings and 3D models.
Depending on the part geometry, our machining work can include:

• Aluminum CNC turning
• CNC lathe machining
• OD and step turning
• Internal and external threading
• Grooving and knurling
• Drilling and tapping
• CNC turn-mill machining
• Secondary CNC machining

For appearance-sensitive parts, we can also coordinate sandblasting, anodizing, polishing and coating according to the customer's finish requirements.
We produce custom aluminum CNC turned parts and precision turned components for consumer products and other industrial applications, from functional internal hardware to visible parts where surface appearance is part of the specification.
 

Need CNC Turning and Finishing in the Same Project?

This project started with a customer drawing—not a catalog part.
The requirement was to produce approximately 3,000 6061-T6 aluminum turned parts with the specified thread, stepped profile, diamond knurl and critical dimensions, then carry those same parts through sandblasting and red anodizing without losing control of the visible surfaces.
That is where machining and finishing need to be considered together.
If you are sourcing similar custom CNC turned parts, send the 2D/3D drawings together with the material grade, quantity, critical tolerances and finish requirements. We can review the complete finished-part requirement before quotation.