303 Stainless Steel CNC Turn-Mill Parts with Diamond Knurling

This custom 303 stainless steel CNC machined part is produced for new energy equipment and supplied to a customer in Canada. The component is approximately 45 × 45 × 30 mm, with repeat orders of around 3,000 pieces per batch.
Its geometry combines features that cannot be handled efficiently as a simple lathe job. The part has a wide circular flange, raised center boss, central bore, multiple face-mounted holes and a prominent diamond-knurled outer surface.
The concentric features are produced mainly by CNC turning, while the mounting-hole pattern requires additional drilling or milling. Knurling adds another controlled operation to the process.
This combination makes the component a good fit for CNC turn-mill machining, where turning and secondary features are planned around the complete part rather than treated as unrelated operations.
 

Part & Production Details

This is a made-to-drawing component. Dimensions, hole positions, internal geometry and knurling requirements follow the customer's engineering drawing.
 

Why This Part Is Not Just a CNC Lathe Job

The flange diameter, raised boss, shoulders, end faces and central bore all share a rotational centerline. These are natural features for precision CNC turning.
The mounting holes are different.
They are distributed around the flange face, away from the main turning axis, so another machining direction is required. Depending on the equipment and production plan, these features can be completed through turn-mill machining or a coordinated secondary operation.
The manufacturing question is therefore not simply:
Can the part be turned?
It is whether the turning, hole machining and knurling can be arranged into a stable production route for approximately 3,000 pieces.
That distinction matters when a prototype moves into repeat production.
 

The Bolt-Hole Pattern Has to Work as a Pattern

For a flange-type component, checking each hole diameter individually does not tell the whole story.
The mounting holes need to correspond with the mating component. Depending on the drawing, the bolt-circle diameter, angular spacing and relationship to the central bore may all influence assembly.
This makes the center bore a useful machining and inspection reference for the surrounding features.
Rather than viewing the flange as “a round part with several holes,” we treat the bore, flange and mounting-hole pattern as related geometry.
Where these relationships are identified as critical on the drawing, they can be included in the project's inspection requirements.
 

Diamond Knurling Needs Its Own Specification

The upper cylindrical section is defined by a diamond-knurled surface, one of the most distinctive features of this part.
Knurling is not simply a decorative finish. Depending on the product design, it can provide grip or another functional contact surface.
For quotation and manufacturing, saying only “knurl this area” may not provide enough information.
Where functionally important, the drawing should ideally define items such as:

• Knurl pattern
• Pitch
• Knurled length
• Required finished diameter
• Any appearance requirements

These details influence tooling and how the knurling operation is planned.
A consistent pattern also needs to be maintained without unnecessarily marking the adjacent smooth-machined surfaces.
For customers sourcing knurled CNC parts, including these requirements on the drawing can reduce uncertainty during quotation and production.
 

Why 303 Stainless Steel Is Well Suited to This Part

The specified material is 303 stainless steel.
303 is commonly used for machined components because its composition gives it better machinability than many other austenitic stainless steels. This can be useful for a component requiring several machining operations, including external turning, internal machining, drilling and knurling.
At a production quantity of around 3,000 pieces, machinability can influence tool life, machining time and process stability.
However, material selection should still be driven by the application. 303 and 304 stainless steel, for example, should not be treated as interchangeable simply because both are stainless steels.
We manufacture according to the material grade specified on the customer's drawing.
 

Protecting the Knurl Is Part of Production

Once the diamond knurl has been formed, the feature still needs to pass through deburring, cleaning, inspection and packing.
This creates a handling consideration that does not exist in exactly the same way on a conventional smooth turned shaft.
Uncontrolled part-to-part contact can mark the flange faces or damage the raised knurled surface. Handling therefore needs to reflect the actual surface requirements of the component.
For export production, packaging is the last part of that process.
The goal is not simply to machine 3,000 acceptable parts, but to have those parts arrive in Canada ready for the customer's next operation.
 

From First Batch to Repeat Production

At approximately 3,000 pieces per batch, process planning needs to balance flexibility with repeatability.
A typical route for this component may include:
Material Preparation → CNC Turning → Bore Machining → Flange-Hole Machining → Diamond Knurling → Deburring → Inspection → Packing
The exact sequence depends on the drawing and equipment used.
Initial parts can be verified before the full production run proceeds, with selected features monitored during machining according to the project's inspection requirements.
For a component like this, inspection may focus particularly on the features that affect assembly: turned diameters, bore dimensions, flange geometry, hole pattern and any specified knurl dimensions.
The purpose is not to inspect every feature more than necessary. It is to control the features that matter to the drawing.
 

Precision CNC Turning and Turn-Mill Services

YS Precision provides precision CNC turning services for custom components that need more than basic rotational machining.
Depending on the drawing, our machining scope can include:

• CNC turning
• CNC lathe machining
• CNC turning and milling
• Turn-mill machining
• Drilling and tapping
• Internal bore machining
• Knurling
• Secondary CNC machining

Typical parts include flanged components, knurled hardware, shafts, pins, bushings, sleeves, connectors and other custom metal parts with both rotational and secondary-machined features.
We machine stainless steel, aluminum, brass, copper, carbon steel and engineering plastics for prototypes, small batches and repeat production.
 

What to Include in Your RFQ

If you are sourcing a CNC turning supplier for a similar component, send us more than the overall dimensions.
For an accurate manufacturing review, we recommend providing:

• 2D drawing and/or 3D model
• Material and grade
• Order quantity
• Critical tolerances
• Bore and thread specifications
• Bolt-hole pattern requirements
• Knurl type, pitch and finished diameter
• Surface requirements
• Inspection requirements
• Expected repeat or annual demand

For turn-mill components like this one, these details help us evaluate the complete manufacturing route before quotation.
Send your drawings to YS Precision for a CNC turning and turn-mill machining review and quotation.