Quick Answer
What is the Sokkia B40?
See also: Topcon AT-B4A Automatic Level Specs
See also: Leica NA524 Automatic Level Specs
The Sokkia B40 is a high-accuracy 32× automatic level with ±1.0mm/km accuracy. It is used for precision construction leveling, floor flatness surveys, settlement monitoring, and control benchmarks where sub-millimeter accuracy is required.
Sokkia B40 Automatic Level — Complete Specs, Manual & Guide
Category: Automatic Level | Brand: Sokkia | Model: B40
The Sokkia B40 is one of the highest-precision optical automatic levels in the construction survey market. At 32× magnification and ±1.0mm/km accuracy, it bridges the gap between standard construction levels and precision geodetic instruments. It is favored by surveyors for structural settlement studies, floor flatness surveys to FF/FL specifications, and network control benchmarks on major infrastructure projects.
Sokkia B40 Full Specifications
| Telescope magnification | 32× |
| Accuracy (std dev per km) | ±1.0mm/km |
| Compensator type | Magnetic damped pendulum |
| Compensator range | ±12 arc minutes |
| Shortest focusing distance | 0.3m |
| Field of view at 100m | 1.8m (1°02') |
| Objective aperture | 45mm |
| Stadia ratio | 100:1 |
| Plate vial sensitivity | 20"/2mm |
| Circular vial sensitivity | 8'/2mm |
| Tripod thread | 5/8" × 11 |
| Weight | 1.9 kg (4.2 lbs) |
| Operating temperature | -20°C to +50°C |
Accessories & Part Numbers
- C20 — Sokkia hard carrying case for B40
- PC-1 — Sokkia parallel plate micrometer (attaches to B40 for 0.01mm reading)
- FB-1 — Sokkia barcode rod (for stadia distance reading)
- Standard aluminum tripod — 5/8" thread, heavy-duty recommended
Frequently Asked Questions — Sokkia B40
What is the accuracy of the Sokkia B40?
The Sokkia B40 achieves ±1.0mm standard deviation per kilometer of double-run leveling. This places it in the high-precision category for optical levels — accurate enough for structural settlement monitoring, floor flatness surveys (FF/FL), and main control networks on infrastructure projects.
How does the Sokkia B40 compare to digital levels?
The B40 at ±1.0mm/km sits between standard construction levels (±2.0mm/km) and high-end digital levels like the Trimble DiNi (±0.3mm/km). For applications requiring repeated measurements without rod reading errors, a digital level is preferred; the B40 excels where an experienced operator needs a reliable, battery-free high-accuracy option.
What is the magnification of the Sokkia B40?
The B40 features a 32× telescope with a 45mm objective aperture — the largest of most automatic levels in its class. The larger aperture gathers more light, improving rod readability at longer distances and in lower-light conditions such as cloudy days and shaded sites.
Can I add a micrometer to the Sokkia B40?
Yes. The Sokkia PC-1 parallel plate micrometer attaches to the front of the B40 telescope and enables readings to 0.01mm resolution on a 3-meter invar rod. This brings the B40 into geodetic leveling territory for bridge surveys and dam settlement monitoring.
What is the difference between the Sokkia B40 and B30?
The Sokkia B30 is a 30× level with ±1.5mm/km accuracy — similar in class to the Topcon AT-B4A. The B40's larger aperture, 32× magnification, and tighter ±1.0mm/km tolerance make it the preferred choice for precision work, while the B30 is the standard construction workhorse.
Related models: Topcon AT-B4A | Leica NA524 | Trimble DiNi 0.3 Digital Level
Track your Sokkia B40 calibration and service history with Gradelog's Equipment Registry. Free to start at gradelog.com.
