The MBF0802.5-3.7 is a flange-type, preload-free, full-ball type ball screw from the THK MBF series in Japan. It belongs to the small outer diameter, small lead positioning type screw category, specifically developed for feed transmission in precision small equipment.
Specifications
Screw outer diameter: 8 mm
Lead: 2.5 mm
Ball center diameter: 8.3 mm
Dynamic load rating: 2.4 kN
Static load rating: 4.1 kN
Nut outer diameter: 20 mm
Flange outer diameter: 38 mm
Nut total length L: 26 mm
Nut weight: 0.07 kg
Screw weight: 0.34 kg/m

THK MBF0802.5-3.7 Full-Ball Type Ball Screw Product Features
All-steel ball structure: No ball retainer, fully filled with steel balls, load capacity superior to cage screws of the same specification; no preload design, smooth operation, low resistance;
Accuracy class: Standard C5 precision grade, optional C3 ultra-high precision, axial clearance GT specification;
DN limit: DN 70000, suitable for miniature high-speed applications; the screw shaft end is unmachined at the original factory, the shaft end and bearing seat can be machined as needed;
Installation method: Single flange through-hole fixing nut, nut fixation, screw rotation, mostly used in small precision transmissions.
Main Application Areas of THK MBF MBF0802.5-3.7 Ball Screw:
1. Semiconductor and Electronics Manufacturing Equipment: Die bonders, dispensing machines, wafer inspection and handling mechanisms
2. Medical Instruments and Bioanalytical Equipment: Automated biochemical analyzers, surgical robot joints, medical imaging equipment
3. Precision Optical and Testing Instruments: Coordinate Measuring Machines (CMMs) and imaging measuring instruments, industrial microscope stages
4. Factory Automation (FA) Micro-mechanisms: Micro-electric cylinders, small robotic gripper mechanisms
5. Laboratory and R&D Testing Equipment: Micro/nano fabrication platforms, precision tensile testing machines, physicochemical analysis instruments
| THK MBF Ball Screw Model | |
| MBF0401-3.7 | MBF0601-3.7 |
| MBF0602-2.7 | MBF0602.5-2.7 |
| MBF0801.5-3.7 | MBF0802-3.7 |
| MBF0802.5-3.7 | MBF0803-2.7 |
| MBF0804-2.7 | MBF1001-3.7 |
| MBF1001.5-3.7 | MBF1002-3.7 |
| MBF1002.5-3.7 | MBF1003-3.7 |
| MBF1005-2.7 | MBF1202-3.7 |
| MBF1202.5-3.7 | MBF1203-3.7 |
| MBF1204-3.7 | MBF1402-3.7 |
| MBF1404-3.7 | |

Model No. |
Screw shaft outer diameterd |
Lead
Ph |
Ball center- to-center diameterdp |
Thread minor diameterdc |
No.of loaded circuitsRows X turns |
Basic load rating | Rigidity
K N/μm |
|
| Ca
kN |
Coa
kN |
|||||||
| MBF 0401-3.7 | 4 | 1 | 4.15 | 3.3 | 1×3.7 | 0.59 | 0.93 | 54 |
| MBF 0601-3.7 | 6 | 1 | 6.15 | 5.3 | 1×3.7 | 0.74 | 1.5 | 75 |
| MBF 0602-2.7 | 6 | 2 | 6.2 | 5.1 | 1×2.7 | 0.75 | 1.2 | 58 |
| MBF 0602.5-2.7 | 6 | 2.5 | 6.2 | 5.1 | 1×2.7 | 0.75 | 1.2 | 59 |
| MBF 0801.5-3.7 | 8 | 1.5 | 8.2 | 7.1 | 1×3.7 | 1.1 | 2.2 | 99 |
| MBF 0802-3.7 | 8 | 2 | 8.3 | 6.6 | 1×3.7 | 2.5 | 4.2 | 111 |
| MBF 0802.5-3.7 | 8 | 2.5 | 8.3 | 6.6 | 1×3.7 | 2.4 | 4.1 | 111 |
| MBF 0803-2.7 | 8 | 3 | 8.3 | 6.2 | 1×2.7 | 2.6 | 4.2 | 85 |
| MBF 0804-2.7 | 8 | 4 | 8.3 | 6.2 | 1×2.7 | 2.6 | 4.2 | 84 |
| MBF 1001-3.7 | 10 | 1 | 10.15 | 9.3 | 1×3.7 | 0.84 | 2 | 113 |
| MBF 1001.5-3.7 | 10 | 1.5 | 10.2 | 9.1 | 1×3.7 | 1.25 | 2.8 | 120 |
| MBF 1002-3.7 | 10 | 2 | 10.3 | 8.6 | 1×3.7 | 2.8 | 5.3 | 134 |
| MBF 1002.5-3.7 | 10 | 2.5 | 10.3 | 8.6 | 1×3.7 | 2.7 | 5.3 | 133 |
| MBF 1003-3.7 | 10 | 3 | 10.3 | 8.2 | 1×3.7 | 3.9 | 7.2 | 140 |
| MBF 1005-2.7 | 10 | 5 | 10.3 | 8.2 | 1×2.7 | 3 | 5.2 | 103 |
| MBF 1202-3.7 | 12 | 12.3 | 10.6 | 1×3.7 | 3 | 6.5 | 156 | |
| MBF 1202.5-3.7 | 12 | 2.5 | 12.3 | 10.6 | 1×3.7 | 3 | 6.4 | 156 |
| MBF 1203-3.7 | 12 | 3 | 12.3 | 10.2 | 1×3.7 | 4.3 | 8.7 | 162 |
| MBF 1204-3.7 | 12 | 4 | 12.3 | 9.8 | 1×3.7 | 5.4 | 10.2 | 165 |
| MBF 1402-3.7 | 14 | 2 | 14.3 | 12.6 | 1×3.7 | 3.3 | 7.5 | 176 |
| MBF 1404-3.7 | 14 | 4 | 14.3 | 11.8 | 1×3.7 | 5.7 | 11.1 | 187 |

Nut dimensions |
Screw shaft inertial moment/mm kg·m²/mm |
Nut
mass kg |
Shaft masskg/m |
||||||||||
| Outer diameterD |
Flange diameter D₁ |
Overall length L₁ |
H | B₁ | PCD | d₁ | d₂ | h | Nut type |
Tw | |||
| 11 | 24 | 18 | 4 | 14 | 17 | 3.4 | 6.5 | 2.5 | I | 13 | 1.97×10-10 | 0.02 | 0.07 |
| 13 | 30 | 21 | 5 | 16 | 21.5 | 3.4 | 6.5 | 3 | I | 17 | 9.99×10-10 | 0.04 | 0.14 |
| 15 | 29 | 17 | 4 | 13 | 23 | 3.4 | Ⅱ | 17 | 9.99×10-10 | 0.03 | 0.21 | ||
| 15 | 29 | 18 | 4 | 14 | 23 | 3.4 | Ⅱ | 17 | 9.99×10-10 | 0.03 | 0.21 | ||
| 16 | 30 | 19 | 4 | 15 | 24 | 3.4 | Ⅱ | 18 | 3.16×10-⁹ | 0.03 | 0.36 | ||
| 20 | 40 | 28 | 6 | 22 | 30 | 4.5 | 8 | 4 | I | 24 | 3.16×10-⁹ | 0.1 | 0.19 |
| 20 | 38 | 26 | 5 | 21 | 30 | 4.5 | Ⅱ | 22 | 3.16×10-⁹ | 0.07 | 0.34 | ||
| 20 | 38 | 25 | 5 | 20 | 30 | 4.5 | Ⅱ | 22 | 3.16×10-⁹ | 0.06 | 0.32 | ||
| 21 | 39 | 28 | 5 | 23 | 31 | 4.5 | Ⅱ | 23 | 3.16×10-⁹ | 0.08 | 0.34 | ||
| 19 | 37 | 18 | 5 | 13 | 29 | 4.5 | Ⅱ | 21 | 7.71×10-9 | 0.04 | 0.57 | ||
| 19 | 37 | 20 | 5 | 15 | 29 | 4.5 | 一 | 一 | Ⅱ | 21 | 7.71×10-9 | 0.04 | 0.57 |
| 23 | 43 | 28 | 6 | 22 | 33 | 4.5 | 8 | 4 | I | 27 | 7.71×10-9 | 0.11 | 0.36 |
| 24 | 44 | 27 | 6 | 21 | 35 | 5.5 | Ⅱ | 26 | 7.71×10-9 | 0.09 | 0.55 | ||
| 24 | 44 | 30 | 6 | 24 | 35 | 5.5 | Ⅱ | 26 | 7.71×10-9 | 0.1 | 0.52 | ||
| 24 | 44 | 34 | 6 | 28 | 35 | 5.5 | Ⅱ | 26 | 7.71×10-9 | 0.12 | 0.56 | ||
| 25 | 47 | 30 | 8 | 22 | 36 | 5.5 | 9.5 | 5.5 | I | 29 | 1.60×10-8 | 0.15 | 0.58 |
| 26 | 46 | 27 | 6 | 21 | 37 | 5.5 | Ⅱ | 28 | 1.60×10-8 | 0.11 | 0.8 | ||
| 28 | 48 | 30 | 6 | 24 | 39 | 5.5 | Ⅱ | 30 | 1.60×10-8 | 0.14 | 0.77 | ||
| 28 | 48 | 33 | 6 | 27 | 39 | 5.5 | Ⅱ | 30 | 1.60×10-8 | 0.15 | 0.76 | ||
| 26 | 48 | 30 | 8 | 22 | 37 | 5.5 | 9.5 | 5.5 | I | 32 | 2.96×10-8 | 0.16 | 0.85 |
| 30 | 54 | 38 | 8 | 30 | 42 | 5.5 | 9.5 | 5.5 | I | 34 | 2.96×10-8 | 0.25 | 1.2 |

