Product Categories / Nuts / Ball Screws and Nuts

Ball Screws and Nuts

186 Products

LILY Bearing stocks 186 ball screws and nuts — in Inch (156 SKUs) and Metric (30 SKUs) — across 5 types: standard, fast-travel, self-stopping, corrosion-resistant, and fast-travel corrosion-resistant. Screws and nuts are listed as separate components; nuts are available in Externally Threaded, Flange, and Platform mounting styles. Use the filters below, or the comparison table, to narrow down by type, thread size, or material.

A ball screw converts rotary motion into smooth, accurate linear motion. Recirculating steel balls roll between the screw shaft and the nut, so friction is low and efficiency is typically around 90% or higher. That means smaller motors, less heat, precise positioning and a long, predictable service life.
Ball screws are the standard choice for CNC machines, electric linear actuators, injection molding machines, semiconductor equipment, robots and automated production lines. Whether you need a single replacement nut or a complete ball screw assembly with support bearings and end blocks, we can help you match the right components to your design.

 

Key Benefits

  • High efficiency with low drive torque
  • Accurate, repeatable positioning
  • High load capacity and rigidity, with preload options to remove backlash
  • Long service life that can be calculated from the load rating
  • Suitable for continuous, high-speed duty

Compare Ball Screw & Nut Types

Type Thread Starts Common Material Best For Watch Out For
Standard Ball Screws and Nuts Single Hardened alloy steel High axial loads needing maximum torque efficiency per revolution Moves less distance per turn than multi-start designs — check travel distance against your drive speed
Fast-Travel Ball Screws and Nuts Multiple Hardened alloy steel Rapid linear motion with high (90%+) mechanical efficiency Faster travel per turn means less torque advantage — confirm your drive supplies enough torque
Self-Stopping Ball Screws and Nuts Varies by SKU Black-oxide alloy steel nut, alloy steel screw Protecting equipment from over-travel damage This is an end-of-travel idle/disengage feature, not a self-locking or anti-backdrive mechanism
Corrosion-Resistant Ball Screws and Nuts Single 17-4 PH stainless steel Moisture, washdown, or mild chemical exposure Lower hardness than standard alloy steel screws — confirm load capacity fits your application
Fast-Travel Corrosion-Resistant Ball Screws and Nuts Multiple 17-4 PH stainless steel Rapid linear motion in corrosive or washdown environments Combines the torque trade-off of multi-start designs with lower stainless hardness — check both specs

 

Screws and Nuts Are Listed Separately

Each listing in this category is either a ball screw (the threaded shaft) or a ball nut (the mating internally-threaded component) — they are not sold as a pre-assembled pair. Ball nuts are available in three mounting styles: Externally Threaded, Flange, and Platform. Match the thread size, thread type, and number of thread starts between the screw and nut you select to ensure they mate correctly.

 

Need a Custom Length or a Part Cross-Reference?

Working from an existing McMaster-Carr or manufacturer part number? Our team can cross-reference it to an equivalent LILY Bearing ball screw or nut, or quote a custom length, thread, or material. Request a Quote or Contact Us.

 

How to Choose a Ball Screw

  • Load: Calculate the axial load and duty cycle, then check the nut’s dynamic load rating and expected life.
  • Speed and Lead: Linear speed equals screw speed times lead. Check the critical speed for the screw length.
  • Accuracy: Choose precision ground screws for tight positioning, or rolled screws when encoder feedback or a looser tolerance is acceptable.
  • Preload: Use a preloaded nut to remove backlash. Higher preload raises stiffness but also adds heat.
  • Mounting: Select fixed–fixed, fixed–supported or fixed–free support to suit your stroke and speed.
  • Environment: Add wipers, bellows or covers where chips, dust or coolant are present.

Frequently Asked Questions

What Is a Ball Screw?

A ball screw is a mechanical drive that turns rotary motion into precise linear motion using recirculating steel balls between a threaded shaft and a nut.

How Do Ball Screws Work?

A motor turns the shaft. The balls roll in the matching raceways of the shaft and nut, pushing the nut along the axis. A return path carries the balls back to the start so they circulate continuously.

What Is the Lifetime of a Ball Screw?

Life is expressed as L10: the number of revolutions that 90% of identical screws reach before fatigue appears. The basic formula is L10 = (Ca / Fm)³ × 10⁶ revolutions, where Ca is the dynamic load rating and

Fm the mean axial load. Lubrication, contamination and alignment also affect real life.

Do Ball Screws Need Lubrication?

Yes. Lubrication reduces wear and heat and protects against corrosion. Use the grease or oil recommended for the nut, and relubricate on a schedule based on speed, load, temperature and environment.

Support bearings need the right lubrication too.

How Can Ball Screw Noise Be Reduced?

Check lubrication first, then alignment, support bearing condition, preload and operating speed. Running near the critical speed or resonance is a common cause of noise.

How Can I Protect a Ball Screw Assembly from Dirt?

Fit wipers or seals on the nut, and add bellows, telescopic covers or an enclosure where chips, dust or coolant are present. Keep the lubricant clean and check the wipers regularly.

How Do I Install a Ball Nut on the Screw?

Keep the nut on its installation sleeve, press the sleeve against the end of the shaft, and turn the nut across without a gap. Do not force it, and do not remove the sleeve in the air, because the balls can fall out.

What Are Ball Screws Used For?

CNC machines, electric actuators, molding and press machines, semiconductor and medical equipment, robots and automated production lines.

What Is the Difference Between a Ball Screw and a Lead Screw?

A ball screw uses rolling contact and is far more efficient, accurate and long-lived. A lead screw uses sliding contact, costs less and can self-lock, so it suits slow, light or occasional-use axes.

Request a Ball Screw Quote

Tell us your shaft size, lead, stroke, load and mounting needs, and our team will recommend suitable ball screws, nuts, support bearings and end blocks. Contact LILY Bearing to request a quote.

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