Product Description
The Linear Flange Bearing LMKC20LUU is a square-flange linear bearing designed for applications that require reliable, low-friction linear motion with solid structural mounting. The square (LMKC-type) flange provides four-point bolt-down mounting, making it well suited for machine frames and structural assemblies where the bearing must be secured in both X and Y axes.
The LUU designation indicates a double-row ball circuit and extended housing length (L = 80 mm vs. 45 mm for the standard LMK20UU). This extended geometry distributes load across a longer contact zone, increasing rigidity and reducing edge loading on the shaft - particularly valuable in applications where moment loads or cantilevered forces are present.
All LMKC series bearings from SIQIANG are manufactured in our 19,800 m² production facility using precision CNC and grinding equipment, and are supplied with documentation for ISO 9001, RoHS, and REACH compliance.
Square flange (LMKC type)
4-bolt mounting, stable in two planes
Double-row ball circuit (LUU)
Extended length for higher moment resistance
5 ball circuits, precision ground raceway, consistent low-friction travel
Compatible with Ø20 h6 precision linear shafts
ISO 9001 certified manufacturing
Full batch traceability available
OEM branding, custom packaging, and sealed variants available on request
Dimensions & Specifications
| Seal Type | Ball Circuit | Dr (mm) | Tolerance (μm) | D (mm) | Tolerance (μm) | L ±0.3 (mm) | Medium Overall Length (mm) | V (mm) | I (mm) | D1 (mm) | K (mm) | H (mm) | PCD (mm) | D1xd2xh | Eccentricity | C (N) | Co (N) | Weight (g) |
| LMFC6LUU / LMKC6LUU | 4 | 6 | 0/-10 | 12 | 0/-13 | 35 | 29 | 12 | 15 | 28 | 22 | 5 | 20 | 3.5x6x3.1 | 323 | 529 | 31 | |
| LMFC8LUU / LMKC8LUU | 4 | 8 | 0/-10 | 15 | 0/-13 | 45 | 37 | 16 | 20 | 32 | 25 | 5 | 24 | 3.5x6x3.1 | 15 | 431 | 784 | 51 |
| LMFC10LUU / LMKC10LUU | 4 | 10 | 0/-10 | 19 | 0/-13 | 55 | 47 | 20.5 | 24.5 | 40 | 30 | 6 | 29 | 4.5x7.5x4.1 | 588 | 1100 | 98 | |
| LMFC12LUU / LMKC12LUU | 4 | 12 | 0/-10 | 21 | 0/-16 | 57 | 47 | 20.5 | 25.5 | 42 | 32 | 6 | 32 | 4.5x7.5x4.1 | 813 | 1570 | 110 | |
| LMFC13LUU / LMKC13LUU | 4 | 13 | 0/-10 | 23 | 0/-16 | 61 | 27.5 | 43 | 34 | 6 | 33 | 4.5x7.5x4.1 | 813 | 1570 | 130 | |||
| LMFC16LUU / LMKC16LUU | 5 | 16 | 0/-10 | 28 | 0/-16 | 70 | 56 | 25 | 32 | 48 | 37 | 6 | 38 | 4.5x7.5x4.1 | 1230 | 2350 | 190 | |
| LMFC20LUU / LMKC20LUU | 5 | 20 | 0/-10 | 32 | 0/-16 | 80 | 65 | 28.5 | 36 | 54 | 42 | 8 | 43 | 5.5x9x5.1 | 1400 | 2740 | 260 | |
| LMFC25LUU / LMKC25LUU | 6 | 25 | 0/-12 | 40 | 0/-19 | 112 | 83 | 37.5 | 52 | 62 | 50 | 8 | 51 | 5.5x9x5.1 | 20 | 1560 | 3140 | 540 |
| LMFC30LUU / LMKC30LUU | 6 | 30 | 0/-12 | 45 | 0/-19 | 123 | 90 | 40 | 56.5 | 74 | 58 | 10 | 60 | 6.6x11x6.1 | 2490 | 5490 | 680 | |
| LMFC35LUU / LMKC35LUU | 6 | 35 | 0/-12 | 52 | 0/-19 | 135 | 62.5 | 82 | 64 | 10 | 67 | 6.6x11x6.1 | 2650 | 6270 | 1020 | |||
| LMFC40LUU / LMKC40LUU | 6 | 40 | 0/-15 | 60 | 0/-22 | 151 | 69 | 96 | 75 | 13 | 78 | 9x14x8.1 | 25 | 3430 | 8040 | 1570 | ||
| LMFC50LUU / LMKC50LUU | 6 | 50 | 0/-15 | 80 | 0/-22 | 192 | 89.5 | 116 | 92 | 13 | 98 | 9x14x8.1 | 6080 | 15900 | 3600 | |||
| LMFC60LUU / LMKC60LUU | 6 | 60 | 0/-20 | 90 | 0/-25 | 209 | 95.5 | 134 | 106 | 18 | 112 | 11x17x11.1 | 30 | 7550 | 20000 | 4500 |
Application Industries
The square-flange form factor and double-row ball circuit make the LMKC20LUU a practical choice wherever a linear bearing must be bolted directly to a structural surface and carry moderate to high loads over a compact stroke. Common deployment areas include:
Industrial Automation
Cartesian robots, pick-and-place units, and linear actuator stages where rigid, repeatable positioning is required.
CNC & Machine Tools
Secondary axis guidance, tooling slides, and adjustable stop assemblies on milling and turning centres.
Packaging Machinery
Film feed systems, carton forming guides, and conveyor transfer units that demand continuous-duty linear travel.
Medical & Lab Equipment
Diagnostic instrument slides, fluid dispensing platforms, and sample handling gantries requiring low backlash.
Printing & Textile Machinery
Print-head carriage guides, fabric tension frames, and needle-bar assemblies running at sustained cycle rates.
Engineering & Logistics
Lift and transfer tables, pallet guidance rails, and telescopic column structures in material handling systems.
Customization & OEM Services
SIQIANG operates an in-house tooling library of over 4,000 patterns and accepts OEM orders with lead times from 7 days (stock items) to 30–45 days (custom configurations). The following modifications are available for the LMKC series:
OEM Branding
Custom laser marking, logo engraving, or neutral packaging available. Private label carton box and bag designs accepted.
Seal Type Options
Open-type or rubber contact-seal variants. Sealed versions improve contamination resistance in dusty or mist environments.
Flange Variant
Round-flange (LMFC) or square-flange (LMKC) available in the same bore size. Specify at order if a different mounting geometry is required.
Documentation & Samples
Sample units available for pre-order validation. Assembly/installation video and CAD drawings provided upon request. 12-month warranty on all shipments.
Why SIQIANG Bearing
Zhejiang SIQIANG Bearing Manufacturing Co., Ltd. is a high-tech enterprise based in Lishui, Zhejiang Province, specialising in linear bearings, linear slides, shaft support units, ball screws, and joint bearings. Since 2007, the company has supplied B2B customers across Southeast Asia, Europe, Africa, and the Americas under the registered brands SQ and SIQIANG. Every batch is manufactured under ISO 9001 quality management and passes a strict multi-stage inspection process before shipment.
2007
Founded
19,800 m²
Production Facility
120+
CNC Machines
50+
Export Countries
Frequently Asked Questions
What shaft diameter and tolerance does the LMKC20LUU require?
The bearing is designed for use with a Ø20 mm linear shaft. For smooth, low-friction operation we recommend a shaft with h6 tolerance (−0 / −13 µm on a 20 mm diameter). Shafts ground to h5 tolerance may be used in higher-precision applications. SIQIANG also supplies matching hardened and ground linear shafts - please contact us if you need a complete shaft-and-bearing assembly.
What is the difference between the LMFC and LMKC flange types?
LMFC features a round circular flange with a bolt-hole pattern around the perimeter, while LMKC uses a square flange with four bolt holes at the corners. The square-flange LMKC design simplifies alignment in rectangular machine frames and provides a more stable, symmetric mounting footprint. Both are available in the same bore range and LUU extended-length variants.
What is the minimum order quantity, and are samples available?
There is no strict minimum order quantity for standard LMKC20LUU units. Sample units can be arranged for qualification testing before a bulk order is placed. For OEM or custom configurations (special sealing, non-standard dimensions, private-label packaging), please contact our sales team to discuss quantities and lead times.
What lubrication is recommended, and what is the service life expectancy?
The bearing ships with a factory-applied grease suitable for general-purpose linear motion. For extended service life, periodic re-lubrication with a lithium-based or EP grease is recommended, particularly in high-cycle or elevated-temperature environments. Applying an anti-rust oil before storage also helps preserve surface condition. SIQIANG offers a 12-month warranty from the date of shipment under normal operating conditions.
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