Ball Screws
Precision Series
High-precision ground ball screws engineered for CNC machine tools, aerospace actuators, and industrial automation. Diameters from Ø6 mm to Ø200 mm — ISO 9001 certified.
High-precision ground ball screws engineered for CNC machine tools, aerospace actuators, and industrial automation. Diameters from Ø6 mm to Ø200 mm — ISO 9001 certified.
Single Nut with Flange — KORTA's precision ground ball screw nut offering high rigidity and compact form. Available in diameters from Ø20 mm to Ø63 mm with leads of 5 mm to 10 mm. Standard right-hand thread; left-hand available on request.
| Model | Diameter (mm) | Lead (mm) | D (mm) | D1 (mm) | D2 (mm) |
|---|---|---|---|---|---|
| RBS-2005 | 20 | 5 | 40 | 52 | 64 |
| RBS-2505 | 25 | 5 | 48 | 60 | 72 |
| RBS-2510 | 25 | 10 | 48 | 60 | 72 |
| RBS-3205 | 32 | 5 | 54 | 66 | 78 |
| RBS-3210 | 32 | 10 | 56 | 70 | 82 |
| RBS-4005 | 40 | 5 | 62 | 76 | 94 |
| RBS-4010 | 40 | 10 | 70 | 88 | 108 |
| RBS-5005 | 50 | 5 | 72 | 90 | 110 |
| RBS-5010 | 50 | 10 | 85 | 105 | 125 |
| RBS-6310 | 63 | 10 | — | — | — |
Shaft rigidity Rs1 is calculated for one end fixed, one end free per metre. For two-end fixed systems, multiply by 4. Nut rigidity Rnu is preloaded to 6% of the dynamic load rating at IT5 tolerance.
| Model | Dynamic Ca (N) | Static Co (N) | Rs1 (N/μm·m) | Rnu (N/μm) |
|---|---|---|---|---|
| RBS-2505 | 12,205 | 31,402 | 91.3 | 297.2 |
| RBS-3205 | 17,791 | 55,131 | 153.7 | 477.5 |
| RBS-3210 | 18,400 | 57,200 | 145.0 | 460.0 |
| RBS-4005 | 24,500 | 76,000 | 210.0 | 630.0 |
| RBS-4010 | 26,800 | 82,000 | 200.0 | 610.0 |
| RBS-5010 | 38,400 | 118,000 | 290.0 | 850.0 |
| RBS-6310 | 52,000 | 162,000 | 380.0 | 1,100 |
The RBS single-nut series is ideal for high-precision positioning in compact machine designs where minimal footprint and direct mounting are priorities.
Axis feed drives requiring high repeatability and minimal backlash.
Precision table feeds with vibration-dampening requirements.
Linear actuator axes demanding compact and stiff drive elements.
Ultra-precise positioning stages in wafer handling and inspection.
High-speed, accurate build platform positioning.
Double Nut with Flange — KORTA's highest-rigidity preloaded series. Two nuts separated by a precision spacer eliminate axial backlash entirely. Available Ø25–63 mm, leads 5–20 mm, with certified load ratings.
| Model | Ø (mm) | Lead (mm) | D (mm) | D1 (mm) | D2 (mm) | X (mm) |
|---|---|---|---|---|---|---|
| UDBS-2505 | 25 | 5 | 40 | 52 | 64 | 12 |
| UDBS-3205 | 32 | 5 | 48 | 60 | 72 | 12 |
| UDBS-3210 | 32 | 10 | 48 | 62 | 75 | 14 |
| UDBS-4005 | 40 | 5 | 56 | 70 | 84 | 16 |
| UDBS-4010 | 40 | 10 | 62 | 78 | 94 | 16 |
| UDBS-5010 | 50 | 10 | 75 | 94 | 112 | 18 |
| UDBS-6310 | 63 | 10 | 90 | 112 | 135 | 22 |
Rs1 = Shaft rigidity, one end fixed / one end free, per metre. Multiply × 4 for two-end fixed systems. Rnu = Nut rigidity preloaded to 6% of dynamic rating at IT5 tolerance.
| Model | Dynamic Ca (N) | Static Co (N) | Rs1 (N/μm·m) | Rnu (N/μm) |
|---|---|---|---|---|
| UDBS-2505 | 12,205 | 31,402 | 91.3 | 297.2 |
| UDBS-3205 | 17,791 | 55,131 | 153.7 | 477.5 |
| UDBS-3210 | 18,400 | 57,200 | 145.0 | 460.0 |
| UDBS-4005 | 24,500 | 76,000 | 210.0 | 630.0 |
| UDBS-4010 | 26,800 | 82,000 | 200.0 | 610.0 |
| UDBS-5010 | 38,400 | 118,000 | 290.0 | 850.0 |
| UDBS-6310 | 52,000 | 162,000 | 380.0 | 1,100 |
UDBS double-nut series is the go-to choice for applications where any backlash is unacceptable and maximum positioning stiffness is critical.
Demanding simultaneous multi-axis movements with zero compliance.
CMM and inspection machines requiring sub-micron repeatability.
Flight control and landing gear where zero backlash is mandatory.
Wire cut and die sink EDM requiring stable, stiff positioning.
Camera and lens positioning platforms demanding micron accuracy.
KORTA's workhorse single-nut ball screw series. BS offers standard single nut with flange, while KBS is a variant with different flange geometry. Both cover Ø8–80 mm diameters in rolled or ground versions for cost-effective precision motion.
| Model | Ø (mm) | Lead (mm) | Dynamic Ca (N) | Static Co (N) |
|---|---|---|---|---|
| BS-8010 | 8 | 10 | 4,264 | 7,106 |
| BS-1210 | 12 | 10 | 8,500 | 12,400 |
| BS-1605 | 16 | 5 | 9,800 | 16,200 |
| BS-2005 | 20 | 5 | 13,500 | 22,000 |
| BS-2010 | 20 | 10 | 14,800 | 24,500 |
| BS-2510 | 25 | 10 | 18,200 | 30,500 |
| BS-3210 | 32 | 10 | 26,400 | 44,800 |
| BS-4010 | 40 | 10 | 36,000 | 62,000 |
| BS-5010 | 50 | 10 | 51,000 | 88,000 |
| BS-8010-4 | 80 | 10 | 90,000 | — |
KORTA offers both rolled (economical, wider tolerances) and ground (precision, tight tolerances) versions across the BS range. Ground versions achieve IT3–IT5 grade; rolled versions are IT7–IT10.
| Grade | Type | Backlash | Accuracy | Typical Use |
|---|---|---|---|---|
| IT3 | Ground | Zero (preloaded) | ±0.004 mm/300mm | High precision CNC |
| IT5 | Ground | Zero / Minimal | ±0.012 mm/300mm | Precision machines |
| IT7 | Rolled | 0.05–0.18 mm | ±0.050 mm/300mm | General automation |
| IT10 | Rolled | 0.10–0.30 mm | ±0.200 mm/300mm | Economy drives |
The BS/KBS series is the most versatile in the KORTA range, covering everything from economy automation to mid-precision machine tools.
Pick-and-place, palletisers, and material handling conveyors.
Fixture actuators and precision vise drives.
Tracker drives, tilt stages, and sample positioning.
High-cycle forming and sealing head drives.
Cost-effective positioning for standard duty cycles.
KORTA's patented rotating nut design keeps the screw stationary while the nut rotates to produce linear motion. This eliminates screw whip at high speeds, allows unlimited stroke length, and enables multi-drive on one shaft.
| Parameter | Rotating Nut | Standard BS |
|---|---|---|
| Critical Speed | Not dependent on length | Dependent on length |
| Max DN Factor | Up to 220,000 | Up to 130,000 |
| Stroke Limit | Unlimited | Limited by whip |
| Inertia | Low (screw fixed) | Higher (screw rotates) |
| Noise / Vibration | Lower | Standard |
| Multi-Drive | Yes | No |
The rotating nut integrates the nut body, support bearing, and bearing balls into one single unit. The support bearing is fixed to the machine table, and the nut rotates within it to drive the fixed screw's carriage linearly.
| Feature | Detail |
|---|---|
| Preload Type | Adjustable (patented system) |
| Max Speed (DN) | 220,000 |
| Dynamic Life | Up to 50% higher vs standard |
| Lubrication | Less required (low heat) |
| Torque | Lower (reduced friction) |
| Heat Generation | Significantly lower |
| Hollow Screw | Optional — coolant / cable routing |
Rotating nut ball screws are selected where high speed, long travel, or multi-head operation is needed without the limitations of conventional ball screws.
Long-travel gantry axes where screw whip would be limiting.
Multiple carriages driven independently on a single screw.
Rapid traverse on large machining center axes (up to DN 220,000).
Elevation systems where smooth, low-vibration motion is key.
AS/RS systems with frequent long-stroke cycling demands.
KORTA's next-generation high-speed ball screw line delivering up to 50% higher dynamic load capacity, DN factor up to 220,000, and significantly lower torque, noise, vibration, and heat generation compared to standard series.
| Performance Metric | Standard Series | High-Speed Series |
|---|---|---|
| Dynamic Load Capacity | Baseline | +50% |
| Max DN Factor | ~130,000 | 220,000 |
| Torque | Baseline | Lower |
| Heat Generation | Standard | Significantly Lower |
| Noise Level | Standard | Reduced |
| Lube Interval | Standard | Extended |
| Service Life | Baseline | +50% estimated |
The high-speed series serves demanding sectors where traditional ball screws become a performance bottleneck.
Actuators in aircraft, satellites, and the International Space Station.
Surgical robot joints, dispensing systems, and diagnostic stages.
Wafer handlers and pick-and-place machines with extreme cycle counts.
Road simulators, dynamometers, and crash test rigs.
High-throughput pipetting, PCR, and analytical instrumentation.
Radar and antenna positioning, turret drives, and periscope systems.
Preload eliminates axial clearance between balls and raceways, improving positioning accuracy, repeatability, and system stiffness. KORTA offers three methods — each optimised for different load and precision requirements.
A precision spacer is inserted between two nuts. The spacer thickness directly controls the preload magnitude — a thicker spacer produces greater preload. This method is used in the UDBS and DBS series.
| Preload Level | % of Dynamic Rating | Application |
|---|---|---|
| Light | 2–4% | Low load, high speed |
| Standard | 6–8% | General precision |
| Medium | 8–12% | Heavy duty CNC |
| Heavy | 12–15% | Max rigidity, low speed |
Balls slightly larger than the ball track groove diameter are inserted, creating 4-point contact between balls and the raceway. This generates a pre-tensioning force without a second nut. Used for small preload levels only, as two contact points experience sliding wear increasing temperature.
| Aspect | Detail |
|---|---|
| Contact Points | 4 (ball to groove) |
| Max Preload | ≤ 4% of dynamic rating |
| Wear Type | Sliding (2 of 4 points) |
| Temperature Rise | Moderate |
| Nut Length | Standard (single nut) |
| Best Use | Light-duty precision drives |
A lead offset is machined into the central area of the nut, dividing it into two internal halves. The offset causes balls to contact the raceway on opposite sides in each half, generating an internal preload force without additional components.
| Aspect | Detail |
|---|---|
| Contact Type | Rolling (all points) |
| Preload Range | 4–10% of dynamic rating |
| Nut Components | Single nut body |
| Adjustability | Fixed at manufacture |
| Heat Generation | Low |
| Best Use | Precision single-nut drives |
Preload must balance precision requirements against friction, heat, and service life trade-offs. Use this guide to select the appropriate method for your application:
| Application Type | Recommended Method | Series |
|---|---|---|
| Max precision + rigidity | Double Nut Spacer (Heavy) | UDBS |
| Precision, compact | Lead Offset Single Nut | RBS |
| Light preload, high speed | Oversize Ball | BS/KBS |
| General CNC axis | Double Nut Spacer (Standard) | UDBS |
| Economy automation | No preload (with backlash) | BS |
| Aerospace / space | Custom ground, preloaded | Custom |
Our engineering team in Pune can help you select the right series, preload level, and dimensions for your specific machine or automation requirement.