Thread Manufacturing in Custom Machining: Cutting vs. Rolling Processes Explained

Threads are one of the most critical functional features in custom machined parts. Whether used for fastening, positioning, or power transmission, the chosen thread manufacturing method has a direct impact on dimensional accuracy, mechanical strength, fatigue performance, assembly reliability, and overall production cost.

From a functional perspective, threads can generally be classified into fastening threads and power transmission threads. From a manufacturing standpoint, thread production is mainly divided into two categories: thread cutting and thread rolling (cold forming).

1. Thread Cutting Processes

Thread cutting refers to forming threads by removing material using cutting tools or abrasive tools. It remains the most versatile and widely used method in custom machining.

Typical thread cutting processes include:

• CNC thread turning

• CNC thread milling

• Tapping and die threading

• Thread grinding

• Thread whirling

During thread turning, milling, or grinding, the machine tool ensures precise synchronization between spindle rotation and axial tool movement, maintaining accurate pitch and profile. In tapping and die threading, the tool advances axially by following the previously formed thread grooves.

Advantages of thread cutting:

• High dimensional accuracy and excellent controllability

• Suitable for non-standard, asymmetric, or special thread profiles

• Applicable to a wide range of materials and hardness levels

• Ideal for prototypes and small-batch production

Typical applications:

• Precision mechanical components

• Instrumentation and medical devices

• Power transmission threads requiring tight tolerances

2. Thread Rolling (Cold Forming)

Thread rolling is a cold forming process in which threads are produced by plastic deformation using hardened rolling dies, rather than material removal. This method is mainly applied to external threads.

Thread rolling is typically performed on thread rolling machines or automatic lathes equipped with rolling heads.

Key benefits of thread rolling:

• Improved fatigue strength due to work hardening

• Lower surface roughness and excellent consistency

• Higher material utilization with no chip loss

• Very high productivity, ideal for mass production

Rolled threads are commonly used in standard fasteners and threaded shafts, especially in high-volume applications where strength and repeatability are critical.

3. Internal Thread Forming (Form Tapping)

For suitable ductile materials, we also offer form tapping for internal threads. This process forms threads through material flow rather than cutting.

Compared with conventional tapping, form tapping provides:

• Higher thread strength

• Better surface finish

• More compact thread structure

However, it requires higher torque and precise pre-hole dimensions, and material suitability must be evaluated during the design stage.

4. How We Support Customers with the Right Threading Solution

There is no single “best” threading process for all applications. The optimal solution depends on multiple factors, including:

• Thread function and load requirements

• Tolerance and assembly conditions

• Material type and hardness

• Production volume and cost targets

• Post-processing requirements

By combining advanced CNC machining with professional thread manufacturing know-how, we support our customers from prototype development to serial production, delivering reliable quality, stable lead times, and cost-effective solutions.