CNC Machining

Technical articles on CNC machining processes, machining problems, tooling, surface finish, tolerances, and practical shop-floor solutions.

5-axis CNC machining an aluminum housing on a tilted rotary table

3-Axis vs. 5-Axis CNC Machining: Which Costs Less for Your Part?

Three-axis CNC machining is often more economical for parts with accessible holes, pockets, and flat surfaces. Five-axis machining can reduce total cost when it avoids repeated setups, complicated fixtures, or difficult tool access. The better choice depends on the part’s geometry, tolerances, and quantity—not the machine’s hourly rate alone.

When ordering custom parts, it is …

CNC machined aluminum housing, cover plate, and bracket with chromate conversion coating

Why Use Chromate Conversion Coating on Aluminum Parts?

Aluminum naturally resists corrosion because it forms a thin protective oxide layer in air. That layer reforms after CNC machining, so machining alone does not make chromate conversion coating necessary. Additional protection becomes useful when moisture, salts, or service conditions demand more than the natural oxide layer can provide.

Chromate conversion coating helps protect machined …

Circular milling diagram showing an end mill and circular toolpath

Circular Milling: How CNC Machines Cut Circular Features

Circular milling uses a rotating cutter traveling around a circular path to machine round holes, pockets, and outside profiles. It is useful when a part needs several opening sizes, a custom-diameter recess, or circular features alongside other milled details. One suitable cutter can produce different diameters by changing its path.

For a customer, the main …

CNC machining workshop with production equipment and aluminum parts

CNC Machining Lead Time: How Long Do Custom Parts Take?

For early planning, allow roughly one to two weeks to manufacture straightforward CNC prototypes when material is available and the drawing is approved. Complex parts and production batches may need several weeks. These are planning estimates, not confirmed delivery dates. Finishing, inspection requirements, and shipping can extend the schedule.

When parts are needed for assembly …

CNC machining supplier factory with multiple machining centers

How to Choose a CNC Machining Supplier for Custom Parts

Choose a CNC machining supplier that has made parts similar to yours, can explain the important details on your drawing, and provides a clear quote with realistic delivery terms. Before placing an order, agree on how the parts will be inspected and what happens if something does not meet the drawing.

The difficult part is …

CNC turning an external thread relief groove

Bearing Fit Tolerance for CNC Machined Parts

A bearing ring exposed to a rotating load normally needs an interference fit to prevent it from creeping on the shaft or inside the housing. A ring exposed to a stationary load can often use a transition or clearance fit. The final tolerance still depends on the bearing type, size, load, temperature, internal clearance and …

Bronze bushing press fit into a CNC machined aluminum housing

Bushing Fit Tolerance for CNC Machined Parts

For a purchased bushing, use the manufacturer’s recommended housing bore instead of calculating the hole from nominal OD alone. For a custom solid bushing, calculate minimum and maximum interference from the bushing OD and housing-bore limits. In both cases, verify the installed ID because press fitting can reduce the final shaft clearance.

This distinction is …

Steel dowel pins for CNC machined parts

Dowel Pin Hole Tolerance for CNC Machined Parts

Dowel pin hole tolerance should be selected according to how the pin works in the assembly. One component normally uses a press-fit hole to retain the pin, while the mating component uses a slip-fit hole for accurate location and easier assembly. Hole diameter alone is not enough. Position, datums, material, coating and inspection also affect …

Radial O-ring groove design for a CNC machined piston

O-Ring Groove Design for CNC Machined Parts

An O-ring groove must compress the seal enough to stop leakage while leaving room for the elastomer to spread and change with pressure and temperature. In a CNC machined part, groove depth, width, surface finish, edge condition, and the mating geometry all affect whether the seal works. A groove can measure correctly and still leak …

Gear machining of precision metal gears

Gear Machining: Process, Methods, Materials, and Types

Gears may look simple, but their teeth have to mesh at the correct position, angle, and spacing for the part to run smoothly. A small error in tooth profile or runout can cause noise, vibration, uneven wear, or poor power transmission.

Gear machining is the manufacturing process used to create the gear blank, cut the

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