719 Series — Light Angular Contact Ball Bearings
The Industry Standard for Machine Tool Spindle Bearing Arrangements
The 719 series is the most widely specified angular contact ball bearing series for CNC machine tool spindles, offering the optimal balance of compactness, speed capability, and load capacity. Its light cross-section accommodates multi-bearing spindle arrangements while maintaining excellent dynamic performance across a wide speed range.
719 Series — Light Angular Contact Ball Bearings
The 719 Series — Light Angular Contact Ball Bearings delivers industry-leading precision and reliability for demanding machine tool spindle applications. Manufactured in our ISO 9001:2015 certified facility in Luoyang, China — the historic heart of bearing manufacturing — each bearing undergoes rigorous dimensional, running accuracy, and vibration testing before shipment.
The SONGJU B719XX light series is the industry workhorse — the most widely specified angular contact bearing for CNC machine tool spindles worldwide. Its optimized cross-section balances compactness with load capacity, making it the most versatile choice across the broadest range of spindle applications. The high ball density design packs more rolling elements than heavier-series alternatives of the same bore, delivering higher radial and axial rigidity — a key advantage in multi-bearing spindle arrangements where load sharing between bearings determines system performance.
The 719 series is available in the widest range of variants of any angular contact series: open or 2RS double-sealed, steel or Si₃N₄ ceramic hybrid balls, standard H high-speed or HQ1 ultra-high-speed configurations, and all three standard preload classes (Light, Medium, Heavy). Bearings are universally face-ground for interchangeable DB/DF/DT mounting without shimming or selective fitting. Precision grades from P5 through P2 ensure the right accuracy-to-cost ratio for every application from general machining to ultra-precision grinding.
719 Series — Light Angular Contact Ball Bearings — Complete Model Parameters
Full model list with α=15° (C) for high-speed and α=25° (AC) for high-rigidity applications. Custom sizes available upon request.
| Model | d | D | B | α=15° (C) — High Speed | α=25° (AC) — High Rigidity | ||||
|---|---|---|---|---|---|---|---|---|---|
| Cr | C0r | Speed | Cr | C0r | Speed | ||||
| 71907 | 35 | 55 | 10 | 11.0 | 10.9 | 26000/40000 | 10.4 | 10.3 | 20000/34000 |
| 71908 | 40 | 62 | 12 | 14.0 | 14.2 | 20000/34000 | 13.3 | 13.5 | 18000/30000 |
| 71909 | 45 | 68 | 12 | 14.7 | 16.1 | 18000/30000 | 13.9 | 15.2 | 17000/28000 |
| 71910 | 50 | 72 | 12 | 19.0 | 21.2 | 17000/28000 | 17.9 | 20.1 | 15000/24000 |
| 71911 | 55 | 80 | 13 | 23.7 | 27.4 | 15000/24000 | 22.4 | 26.0 | 14000/22000 |
| 71912 | 60 | 85 | 13 | 24.8 | 30.3 | 14000/22000 | 23.3 | 28.7 | 13000/20000 |
| 71913 | 65 | 90 | 13 | 25.1 | 31.9 | 13000/20000 | 23.6 | 30.2 | 12000/19000 |
| 71914 | 70 | 100 | 16 | 34.5 | 43.4 | 12000/19000 | 32.6 | 41.2 | 11000/18000 |
| 71915 | 75 | 105 | 16 | 25.0 | 45.6 | 11000/18000 | 33.0 | 43.2 | 9500/16000 |
| 71916 | 80 | 110 | 16 | 35.5 | 47.8 | 10000/17000 | 33.5 | 45.3 | 9000/15000 |
| 71917 | 85 | 120 | 18 | 46.5 | 61.9 | 9500/16000 | 43.8 | 58.6 | 8500/14000 |
| 71918 | 90 | 125 | 18 | 47.2 | 64.8 | 9000/15000 | 44.5 | 61.4 | 8000/13000 |
| 71919 | 95 | 130 | 18 | 47.9 | 67.8 | 9000/15000 | 45.2 | 64.1 | 8000/13000 |
| 71920 | 100 | 140 | 20 | 60.4 | 84.4 | 8500/14000 | 56.9 | 79.9 | 8000/13000 |
| 71921 | 105 | 145 | 20 | 61.4 | 88.2 | 8000/13000 | 57.8 | 83.5 | 7500/12000 |
| 71922 | 110 | 150 | 20 | 62.3 | 91.9 | 7500/12000 | 58.7 | 87.0 | 7000/11000 |
| 71924 | 120 | 165 | 22 | 73.7 | 107.6 | 7000/11000 | 69.5 | 101.9 | 6700/10000 |
| 71926 | 130 | 180 | 24 | 76.3 | 117.1 | 6700/10000 | 71.9 | 110.9 | 6000/9000 |
| 71928 | 140 | 190 | 24 | 78.9 | 126.4 | 6000/9000 | 74.4 | 119.7 | 5600/8500 |
| 71930 | 150 | 210 | 28 | 118.2 | 175.1 | 5600/8500 | 111.4 | 165.8 | 5000/7500 |
| 71932 | 160 | 220 | 28 | 123.6 | 191.2 | 5000/7500 | 116.5 | 181.1 | 4800/7000 |
| 71934 | 170 | 230 | 28 | 125.7 | 200.0 | 4800/7000 | 118.5 | 189.4 | 4300/6300 |
| 71936 | 180 | 250 | 33 | 159.7 | 249.1 | 4500/6700 | 150.6 | 235.9 | 4000/6000 |
| 71938 | 190 | 260 | 33 | 162.8 | 260.8 | 4300/6300 | 153.5 | 247.0 | 3800/5600 |
| 71940 | 200 | 280 | 38 | 198.4 | 311.4 | 3800/5600 | 187.1 | 294.9 | 3600/5300 |
| 71944 | 220 | 300 | 38 | 206.6 | 341.1 | 3600/5300 | 194.8 | 323.0 | 3200/4800 |
| 71948 | 240 | 320 | 38 | 219.2 | 384.2 | 3200/4800 | 206.7 | 363.8 | 3000/4500 |
| 71952 | 260 | 360 | 46 | 284.6 | 528.8 | 3000/4500 | 268.3 | 500.8 | 2600/4000 |
| 71956 | 280 | 380 | 46 | 288.7 | 554.6 | 2600/4000 | 272.2 | 525.5 | 2200/3600 |
All models available in P5, P4, and P2 precision grades. H-prefix = high-speed variant, HQ1 suffix = ceramic hybrid (Si₃N₄ balls). Phenolic, PEEK, or machined brass cages. Contact our engineering team for specific preload and arrangement recommendations.
Configuration Options for 719 Series Angular Contact Ball Bearings
Luoyang Songju offers multiple design variants to meet the full spectrum of spindle design requirements. Below are the standard configuration options available across the 719 series.
Mounting Configuration
Single universally ground bearing (U) for individual mounting, or matched sets: Duplex / D (two bearings), Triplex / T (three bearings), Quadruplex / Q (four bearings) in DB, DF, or DT arrangements.
Universal Matching
Precision face-ground for universal pairing. Interchangeably mount any two bearings of the same size in DB (back-to-back), DF (face-to-face), or DT (tandem) without shims or selective fitting.
Ball Material
Standard: premium GCr15 (100Cr6 / 52100) hardened steel balls. Hybrid option: Si₃N₄ silicon nitride ceramic balls — 40% lighter, lower thermal expansion, superior high-speed performance.
Sealing Options
Open bearings for oil-mist or oil-air lubrication systems. 2RS sealed variant with non-contact rubber seals on both sides for grease-lubricated, contamination-protected applications.
Direct Lubrication
Optional circumferential lubrication groove and radial oil holes in the outer ring for direct oil injection — ensures reliable lubricant delivery at ultra-high speeds.
Preload Classes
Three standard preload levels: Light (L) for maximum speed and minimal heat; Medium (M) for balanced rigidity and speed; Heavy (H) for maximum stiffness in rigid spindle systems.
719 Series Recommended Configuration
For optimal performance in general CNC spindle applications, we recommend: Medium (M) preload + 15° (C) contact angle + Phenolic cage. For high-speed finishing spindles, substitute Light (L) preload and HQ1 ceramic hybrid balls. For heavy turning centers, substitute 25° (AC) contact angle and Heavy (H) preload.
How to Select 719 Series — Light Angular Contact Ball Bearings
Understanding your application requirements is the first step to specifying the correct bearing configuration. Below are the key selection parameters and recommendations for the 719 series.
1 Determine Contact Angle
Choose for high-speed applications where radial stiffness is the priority. Lower axial stiffness but permits significantly higher rotational speeds. Ideal for grinding spindles and high-speed machining.
Choose when maximum axial rigidity and combined load capacity are required. Higher axial load capacity suits turning centers, milling spindles, and applications with substantial thrust forces.
2 Select Precision Grade
| Grade | ABEC | Radial Runout (max) | Bore Tolerance | Typical Application |
|---|---|---|---|---|
| P5 | ABEC-5 | ≤ 0.004mm | +0 / -0.008mm | General machine tool spindles, pumps |
| P4 | ABEC-7 | ≤ 0.002mm | +0 / -0.005mm | CNC machining centers, precision grinding |
| P2 | ABEC-9 | ≤ 0.001mm | +0 / -0.003mm | Ultra-precision spindles, CMM, optical grinding |
3 Choose Bearing Arrangement
4 Specify Preload and Lubrication
Light preload (L) — Best for high-speed finishing spindles and grinding applications where thermal stability takes priority over cutting stiffness.
Medium preload (M) — Recommended for 719 Series. The optimal balance for most CNC machining center spindles. Provides sufficient rigidity for both roughing and finishing while maintaining competitive speed limits.
Heavy preload (H) — Use for turning center spindles and heavy milling applications where cutting forces dominate. Combine with 25° contact angle for maximum axial stiffness.
719 Series Lubrication Recommendation: Grease (standard, suits most applications up to ~15,000 r/min). Oil-air lubrication recommended for sustained operation above 15,000 r/min. The H and HQ1 high-speed variants with optimized internal geometry provide up to 40% higher speed limits versus standard designs.
Cage Materials, Lubrication & Precision Tolerances
Detailed technical specifications to support proper bearing selection and application engineering for 719 Series — Light Angular Contact Ball Bearings.
Cage Material Selection
| Material | Max Operating Temp | Speed Suitability | Best For | Available Series |
|---|---|---|---|---|
| Phenolic Resin | 120°C | High speed | Standard spindle applications; lightweight, low friction | 718 / 719 / 70 / 72 |
| PEEK | 250°C | Very high speed | High-temperature spindles; superior chemical resistance | 718 / 719 / 70 / 72 |
| Machined Brass | 300°C | Moderate speed | Heavy-duty / shock loads; maximum strength & durability | 70 / 72 (recommended) |
| Polyamide (PA66) | 100°C | Moderate speed | Cost-effective; general industrial, non-spindle use | 70 / 72 |
Lubrication Method Comparison
| Method | Speed Factor (dmN) | Cooling | Complexity | Best Application |
|---|---|---|---|---|
| Grease | Up to 1.0 × 10⁶ | None | Low | Standard spindles, periodic maintenance OK |
| Oil-Mist | Up to 1.5 × 10⁶ | Minimal | Medium | High-speed grinding, continuous operation |
| Oil-Air | Up to 2.0 × 10⁶ | Good | Medium-High | Ultra-high-speed spindles, ceramic hybrids |
| Oil-Jet | Up to 2.5+ × 10⁶ | Excellent | High | Maximum speed; requires oil recovery system |
| Direct Lubrication | +15–20% vs standard | Application-dependent | Medium | Optimizes delivery via outer ring groove & radial holes |
Speed factor (dmN) = pitch diameter [mm] × rotational speed [r/min]. Values are indicative — actual limits depend on bearing size, preload, and cage material.
Precision Grade Tolerance Table (ISO 492)
| Parameter | Symbol | P5 (ABEC-5) | P4 (ABEC-7) | P2 (ABEC-9) |
|---|---|---|---|---|
| Bore deviation (nominal d ≤ 80mm) | Δdmp | 0 / -8 μm | 0 / -5 μm | 0 / -3 μm |
| Bore deviation (80 < d ≤ 180mm) | Δdmp | 0 / -10 μm | 0 / -7 μm | 0 / -4 μm |
| Bore deviation (180 < d ≤ 250mm) | Δdmp | 0 / -15 μm | 0 / -10 μm | 0 / -5 μm |
| OD deviation (nominal D ≤ 150mm) | ΔDmp | 0 / -9 μm | 0 / -6 μm | 0 / -4 μm |
| OD deviation (150 < D ≤ 250mm) | ΔDmp | 0 / -13 μm | 0 / -8 μm | 0 / -5 μm |
| Inner ring radial runout | Kia | ≤ 4 μm | ≤ 2 μm | ≤ 1 μm |
| Outer ring radial runout | Kea | ≤ 5 μm | ≤ 3 μm | ≤ 1.5 μm |
| Axial runout (inner ring face) | Sia | ≤ 5 μm | ≤ 3 μm | ≤ 1.5 μm |
| Width tolerance (all sizes) | ΔBs | 0 / -40 μm | 0 / -25 μm | 0 / -15 μm |
Industries & Applications for 719 Series — Light Angular Contact Ball Bearings
719 Series — Light Angular Contact Ball Bearings are trusted across a wide range of precision industries worldwide. Below are the primary application areas where the 719 series delivers measurable performance advantages.
CNC Machining Centers
The industry-standard choice for vertical and horizontal machining center spindles. Front and rear bearing sets in DB or DF arrangements with Light or Medium preload.
Precision Grinding Spindles
External and internal grinding spindles requiring P4 or P2 precision grades for sub-micron workpiece roundness and surface finish.
CNC Lathes & Turning Centers
Main spindle and sub-spindle bearing arrangements where high rigidity under radial cutting loads must combine with thermal stability for long production runs.
Milling Spindles
High-torque milling spindles where the 719 series optimized speed-to-load ratio handles both heavy roughing cuts and high-speed finishing passes.
Precision Rotary Axes
Rotary tables, tilting axes, and 5-axis trunnion drives requiring high axial rigidity and consistent positioning accuracy under dynamic loading.
Automotive Assembly Lines
High-volume production spindles in transfer lines and flexible manufacturing cells — 719 bearings deliver the reliability and consistency required for 24/7 operation.
High-Frequency Spindles
Motorized spindles for micro-machining and PCB drilling, where P2-grade 719 bearings with ceramic balls achieve dmN values exceeding 1.8 × 10⁶.
Coordinate Measuring Machines
Ultra-precision rotary axes in CMMs and gear measuring centers demanding the lowest possible radial and axial runout.
Why Choose Luoyang Songju 719 Series — Light Angular Contact Ball Bearings
The 719 series is the most widely specified angular contact ball bearing series for CNC machine tool spindles, offering the optimal balance of compactness, speed capability, and load capacity. Its light cross-section accommodates multi-bearing spindle arrangements while maintaining excellent dynamic performance across a wide speed range.
Most Versatile Series
The industry-preferred choice for machining center spindles, grinding spindles, and precision rotary axes. Available in open and 2RS double-sealed variants.
Optimized Speed-to-Load Ratio
Goldilocks cross-section — compact enough for high speeds, robust enough for real cutting loads. Grease speed limits up to 26,000 r/min.
High Ball Density
More balls than 72 series for the same bore, providing higher radial and axial rigidity — a key advantage in multi-bearing spindle arrangements.
Universal Ground Faces
Precision face-ground for universal matching. Mix bearings freely in DB, DF, DT arrangements without shimming.
H/HQ1 Speed Variants
H-prefix high-speed and HQ1 ceramic hybrid variants provide up to 70% higher speed limits for ultra-high-speed spindle applications.
ISO Interchangeable
Drop-in replacement for NSK, SKF, FAG, NTN, and Timken 719-series precision bearings. Same dimensions, equivalent or better performance.
Need 719 Series — Light Angular Contact Ball Bearings?
Tell us your bore size, contact angle, precision grade, preload class, and quantity — our application engineers will respond within 24 hours with a competitive quotation and detailed technical documentation.