High-Speed 7911AC Angular Contact Bearings for CNC Engraving Spindles
| Item No : | 7911AC / 71911AC |
| Size (d*D*B) : | 55x80x13mm |
| Material : | Chrome Steel GCr15 |
| Lead Time : | 3-5 days |
| Weight : | 0.17KG |
| MOQ : | 10 pcs |
| Service : | Support Sample Testing |
⚙️Product Description:
The 7911AC (55x80x13mm) is a high-precision, ultra-light series (ISO 09 series) angular contact ball bearing engineered specifically for high-speed CNC machine tool spindles and precision rotating heads. Featuring a 55mm inner bore, 80mm outer diameter, and a slim 13mm width, its 25-degree (AC) contact angle offers an exceptional balance between high rotational speed capabilities and axial load-carrying rigidity. Built with premium GCr15/52100 chrome steel and precision-guided cages, it excels in preloaded back-to-back (DB), face-to-face (DF), or tandem (DT) matched sets. We supply these high-speed spindle bearings under our proprietary RMO brand while facilitating flexible multi-brand OEM procurement for global machine tool builders and spindle repair specialists.
⚙️Product Features:
- 25° Contact Angle (AC) Design: Delivers an optimal stiffness-to-speed ratio, providing robust unidirectional axial support while maintaining ultra-low temperature rise at elevated RPMs.
- ISO 09 Ultra-Light Cross Section: Minimal outer diameter and width profile maximize internal spindle shaft clearance and minimize centrifugal force on rolling elements.
- Matched Set Precision: Precision-ground face flushness enables seamless pairing in DB, DF, or DT configurations with predefined preload levels (Light, Medium, Heavy).
- High-Speed Kinematic Stability: Micro-honed raceways combined with phenolic resin or polyamide cages minimize friction torque, vibration, and thermal expansion during continuous machining.
⚙️Product Applications:
Engineered for elevated rotational speeds, strict axial rigidity, and minimal thermal growth, the 7911AC bearing is widely specified in:
- CNC machine tool spindles: high-speed milling spindles, engraving machine heads, and motorized internal grinding spindles.
- Precision metalworking & woodworking: wood carving router spindles, PCB drilling heads, and automatic tool changer (ATC) units.
- Test rigs & high-speed machinery: turbocharger test benches, high-frequency motor shafts, and centrifugal separators.
- Optical & semiconductor hardware: precision rotary positioning stages, indexing tables, and wafer polishing heads.
⚙️Precautions:
| 1. Keep clean | 2. Use with caution | 3. appropriate tool | 4. Hot-loading | 5. Be careful of rust |
| Dust will have a bad effect on the bearing, so keep the surrounding clean. | Strong impact during use can easily cause scratches and indentations. | Avoid replacing existing tools, and use appropriate tools. | Bearings are precision parts, so hot installation is recommended. | Sweat on your hands during operation will cause rust, so it is best to wear gloves. |
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⚙️Obtain Certificate:
About Rimao
Since its establishment in 2011, Rimao Bearing has combined international vision with local wisdom and injected innovative ideas into every bearing and pulley with its profound industry accumulation and unremitting pursuit of technology. We have not only passed CE and ROHS certification, but also set a new benchmark in the industry and led the development trend of the bearing industry.
We are not just a ball bearing and roller bearing importer and wholesaler. We provide real solutions to help you achieve the product and design goals set by your customers. With more than 20 years of production and sales experience, tens of thousands of models and specifications, we look forward to cooperating with you!
⚙️Technical Parameters:
| Model / Industry No. | 7911AC / 71911AC |
| Bearing Type | Ultra-Light Angular Contact Ball Bearing |
| Dimensions | 55x80x13mm (Inner d x Outer D x Total Width/Height H) |
| Contact Angle | 25° (AC Type – High Speed & Axial Rigidity) |
| Ring & Ball Material | High Precision GCr15 Chrome Bearing Steel |
| Cage Material | Phenolic resin (standard), optional brass or glass fibre reinforced PA66 |
| Precision Grade | ABEC-1 to ABEC-7 (P0 to P4) |
| Preload & Matching | Universal Matching (DB, DF, DT) / Light, Medium Preload |
| Target Application | CNC Spindles, Engraving Heads, PCB Drills |
| Brand | RMO (Own Brand) / Neutral / OEM Custom / Other Global Brands |
| Package | Individual plastic bag, plastic tube or original RMO brand box |
| Lead Time | 3-5 days for stock; 7-15 days for bulk orders |
| Shipping | Express (DHL/FedEx/UPS), Air Freight, Sea Freight |
| Payment | 100% TT, or 30% TT In Advance, 70% TT After Finished Production |
| Model No. | d | D | H | m |
| 71900AC | 10 mm | 22 mm | 6 mm | 10 g |
| 71901AC | 12 mm | 24 mm | 6 mm | 11 g |
| 71902AC | 15 mm | 28 mm | 7 mm | 16 g |
| 71903AC | 17 mm | 30 mm | 7 mm | 18 g |
| 71904AC | 20 mm | 37 mm | 9 mm | 37 g |
| 71905AC | 25 mm | 42 mm | 9 mm | 43 g |
| 71906AC | 30 mm | 47 mm | 9 mm | 50 g |
| 71907AC | 35 mm | 55 mm | 10 mm | 77 g |
| 71908AC | 40 mm | 62 mm | 12 mm | 100 g |
| 71909AC | 45 mm | 69 mm | 12 mm | 117 g |
| 71910AC | 50 mm | 72 mm | 12 mm | 117 g |
| 71911AC | 55 mm | 80 mm | 13 mm | 174 g |
| 71912AC | 60 mm | 85 mm | 13 mm | 188 g |
| 71913AC | 65 mm | 90 mm | 13 mm | 200 g |
| 71914AC | 70 mm | 100 mm | 16 mm | 340 g |
| 71915AC | 75 mm | 105 mm | 16 mm | 359 g |
| 71916AC | 80 mm | 110 mm | 16 mm | 376 g |
| 71917AC | 85 mm | 120 mm | 18 mm | 533 g |
| 71918AC | 90 mm | 125 mm | 18 mm | 559 g |
| 71919AC | 95 mm | 130 mm | 18 mm | 583 g |
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