Tolerance is especially important in the automotive, electronics, and aerospace sectors, where even one minor deviation can lead to catastrophic failures or costly recalls.

One way to ensure part tolerances are met is through screw machining. In this blog, we’ll explore the role that screw machining plays in maintaining these stringent standards.

Tolerance Standard in Screw Machining

Screw machining is known for its ability to achieve exceptionally high tolerances. The standard in screw machining and any method used to create precision components is +/- 0.005.” However, some advanced setups that incorporate CNC technology can achieve even tighter precision. CNC technology supports tolerances as fine as +/- 0.0001.”

The specific tolerance limits can vary based on factors such as the material used, part complexity, and the specific type of screw machine used. In the sections below, we’ll discuss how some of these factors influence tolerances.

Factors That Influence Tolerances

Application

The application environment is the most significant factor influencing the tolerances required for screw-machined parts like bushings, spacers, and connectors.

Parts exposed to temperature extremes must accommodate thermal expansion and contraction. Tighter tolerances help reduce the risk of fitment issues or mechanical failures.

Similarly, components subjected to high mechanical stress must have tolerances that allow them to maintain integrity under load without compromising their functionality.

Part Size

Part size also plays a critical role in determining the tolerances achievable through screw machining. Smaller components often require tighter tolerances because minor deviations can significantly impact their function and fit within an assembly. Conversely, larger parts may accommodate slightly looser tolerances due to their size and the relative impact of variations.

However, the precision level still needs to be adjusted based on the part’s specific function and the precision required for it to operate effectively within its mechanical system.

Design Complexity

More intricate designs, with features like thin walls, complex curves, or tight clearances, require stricter tolerances to ensure the part functions as intended. For example, angular tolerances in machining can range from +/- 0.5 degrees for less critical applications to as precise as +/- 0.1 degrees for high-precision needs.

Engineers must carefully balance the design complexity with achievable tolerances, ensuring that the parts are manufacturable while meeting functional and operational requirements.

Material

The material used in screw machining also influences the achievable tolerances due to each material’s properties.

Metals

Metals like brass and aluminum are generally more malleable, allowing for tighter tolerances and easier machining. Brass, for instance, can often be machined to tolerances as tight as +/- 0.0005” due to its softness and ductility. Aluminum, while slightly harder, still maintains high machinability with similar tolerances.

Stainless steel, being harder and more abrasive, often requires slightly looser tolerances, typically around +/- 0.001,” as it is more demanding on machining tools and can wear them down faster.

Polymers

Conversely, polymers like nylon and PEEK behave differently than metals. These materials are softer and more prone to deformation under machining stress, thermal expansion, and moisture absorption. This variability can affect the precision of the final product, often requiring looser tolerances compared to metals. Tolerances for polymers might range from +/- 0.002 to +/- 0.010,” depending on the specific conditions of the machining process and the part’s application requirements.

Machining Method

Lastly, the chosen machining method and the conditions under which machining takes place will influence achievable tolerances.

For example, traditional screw machining might offer different precision capabilities compared to CNC machining, which provides greater control over cutting speeds, tool movements, and more complex part geometries. Additionally, machining conditions such as tool wear, machine stability, and the presence of lubricants can impact the quality of the finished product. Tool wear can lead to less precise cuts, while machine instability and inadequate lubrication impact accuracy and surface finish, directly affecting the tolerances.

Learn More From GreatLight

Founded in 1995, GreatLight is a specialty manufacturer helping Tier I and Tier II suppliers worldwide. Our capabilities include single- and multi-spindle CNC Swiss screw machining, investment casting, custom shaft manufacturing, prototyping, forging, and more. We can manufacture screw-machined parts up to 24” in length and 3” in diameter and can achieve tolerances within +/-.001.″ We also offer a just-in-time delivery program for customers in the United States, Mexico, Canada, and Western Europe.

Please contact us today to learn more about our screw machining capabilities or visit our blog for more resources.

As the name suggests, this method uses multiple spindles, typically mounted on a rotating drum, to machine workpieces simultaneously, which offers many benefits.

In this article, we’ll cover what those benefits are.

Faster Lead Times

Multi-spindle screw machining significantly enhances production rates, making it one of the best methods for large-scale orders. By using multiple spindles at the same time, manufacturers can produce several parts simultaneously, dramatically increasing throughput compared to single-spindle machines, without compromising quality.

Consistent Quality

Multi-spindle machining also maintains high precision and uniformity across parts made from a variety of materials. The synchronized operation of multiple spindles ensures each part undergoes the same machining process, delivering consistent quality regardless of whether the material is plastic or metal. This consistency is especially vital in industries like aerospace, automotive, and medical devices, where precision is non-negotiable.

Reduced Operational Costs & Waste

Many parts of the multi-spindle machining process can and are automated, reducing the need for manual intervention and allowing a smaller workforce to manage large-scale production effectively. This method also minimizes waste through its high precision and efficient nature—its accuracy means that each part is machined to exact specifications, reducing the likelihood of errors that lead to material wastage. Additionally, the advanced control systems in multi-spindle screw machines allow for more precise material usage, ensuring every bit of material is used effectively.

Compatible With Many Materials

Multi-spindle machining is versatile, meaning that it is compatible with a wide range of materials, from tougher materials like stainless steel to softer metals like aluminum, brass, and copper, plastics, and other composites. Most multi-spindle machines are equipped with advanced control systems and variable spindle speeds, allowing them to adjust to the unique properties of different materials automatically.

Part Design Flexibility

Lastly, multi-spindle machines can be set up to follow specific design parameters, meaning that various components can be made simultaneously with different dimensions, thread patterns, and other specialized features. This flexibility is crucial for industries requiring custom components for specific applications where standard sizes and shapes are not sufficient.

GreatLight Offers Precision Multi-Spindle Machining

Are you interested in learning more about multi-spindle screw machining? Reach out to GreatLight today.

Founded in 1995, we’re an OEM-approved Tier 1 & Tier II parts manufacturer offering many capabilities, including single- and multi-spindle screw machining, to businesses throughout the United States, Mexico, Canada, and Western Europe. We use Swiss screw machines to produce millions of pieces per SKU annually. We can manufacture components up to 24 inches long with an outer diameter of up to three inches and tolerances of +/-.001 inch. Our multi-spindle operations include form turning, drilling, reaming, boring, thread rolling, and more.

Please contact us to learn more about our capabilities or to request a quote.