Sanfeng three-point internal micrometer 368 model maintenance

Sanfeng three-point internal micrometer 368 model maintenance

1、 Core features and working principle of three-point contact measurement: This is the most core feature of this series of micrometers. There is a precise spiral cam structure inside the measuring head, which synchronously drives the three measuring claws when the micrometer head is rotated

Extend uniformly radially from the center, ensuring that all three measuring points are in contact with the wall of the tested hole simultaneously. Advantages: Automatic centering: The three-point contact can automatically find the center of the hole, minimizing errors introduced by the measurer's operation of tilting or finding large diameter values. High measurement accuracy: It directly measures the true diameter of the hole, not the chord length, resulting in more accurate results. Good repeatability: Due to its stable centering ability, different operators or the same operator can obtain very consistent results after multiple measurements. The 368 series offers multiple precision levels, with measurement accuracy typically reaching ± 2 μ m or even higher (depending on the range). Combined with Sanfeng's high-quality mechanical scale sleeve and ratchet force measuring device, accurate readings of 1 μ m can be achieved. The 368 series with wide range and multiple specifications is not a single model, but a series that covers a wide range from small aperture to large aperture. The common range ranges include: 3.5-4.5mm, 4.5-5.5mm (for extremely small apertures) 5-25mm, 25-45mm (for commonly used small apertures) 50-100mm, 100-160mm ... up to 400-1000mm or even larger (large aperture), users can choose the appropriate model according to the size of the tested hole. Humanized design and high-quality manufacturing of insulation board: The ruler frame is equipped with insulation board to prevent hand temperature from affecting the thermal expansion of the ruler body, ensuring measurement stability. Hard alloy probe: The top of the three measuring claws is embedded with hard alloy, which is extremely wear-resistant and extends the service life. Locking device: convenient for locking the measured value during reading. Ratchet stopper/friction cylinder: Provides a constant measuring force to ensure consistent contact force with the workpiece during each measurement, avoiding measurement values being underestimated or damaging the workpiece due to excessive force. 2、 The main application areas of the 368 series three-point inside micrometer are suitable for all occasions that require high-precision aperture measurement: engine manufacturing and testing: cylinder holes, connecting rod holes, bearing seat holes, etc. Hydraulic and pneumatic components: inner hole diameter of valve body, oil cylinder, pump body, etc. Precision molds: mold cavity, guide column holes, etc. Bearing industry: Inner diameter of bearing seat. Research and Quality Testing Laboratory. 3、 Basic operating steps for cleaning: Before use, be sure to clean the three measuring jaws of the micrometer and the inner hole of the workpiece being measured. Zero calibration: For small-sized models, matching ring gauges can be used for calibration. Put the micrometer into the ring gauge, rotate the ratchet until it makes a "click" sound, and then adjust the dial to align the "0" position. Measurement: Gently place the probe into the hole, approximately at the center of the hole. Positioning: Gently swing the micrometer to find the minimum value (indicating the point with the smallest reading) in the axial and radial directions of the hole. Due to the three-point automatic centering, this minimum value is the true diameter of the hole. Reading: After finding the minimum value, lock the device and take out the micrometer for reading. The reading method is similar to that of a regular external micrometer: primary scale+secondary scale. 4、 The model naming convention "Sanfeng 368" is the series name, and the specific model will include range information. For example, 368-312 may represent a model with a range of 12.5-15.0mm. 368-341: May represent models with a range of 50-63mm. When selecting a specific model, it is necessary to determine based on the aperture range you want to measure. 5、 Advantages summary: High precision: ± 2 μ m level accuracy, meeting the vast majority of precision machining needs. True diameter measurement: Three point design directly measures diameter, not chord length. Excellent repeatability: The automatic centering function allows measurement results to be independent of the operator's skills. Stable and reliable: Sanfeng brand has good quality and durability. Note that the price is relatively high: due to its complex built-in structure and high precision, the price of three-point internal micrometers is much higher than two-point or caliper measuring tools. Maintenance required: As a precision instrument, it should be used with care, calibrated regularly, and kept clean. Single axial measurement: Only the diameter of one section can be measured at a time. To measure roundness and cylindricity, multiple measurements need to be taken at different sections and directions. In summary, the Sanfeng 368 series three-point inside micrometer is a tool for high-precision aperture measurement. If you have strict requirements for the dimensional accuracy and roundness of the hole, it is a very ideal choice.Sanfeng three-point internal micrometer 368 model maintenance