Marble parallel gauge for measuring workpiece straightness and flatness, as well as equipment installation. Granite parallel gauge material is granite, mainly composed of gneiss, plagioclase, a small amount of olivine, biotite, and trace magnetite, with a black color and a fine structure.

Marble parallel gauges are used for measuring the straightness and flatness of workpieces and for equipment installation. The granite parallel gauge is made of granite, primarily composed of andesite, plagioclase, a small amount of olivine, biotite, and trace amounts of magnetite. It features a black color, a fine structure, and has undergone billions of years of aging, resulting in uniform texture, good stability, high strength, and hardness. It can maintain high precision under heavy loads and possesses advantages such as non-corrosiveness, wear resistance, non-magnetization, and non-deformation, making it suitable for industrial production and laboratory measurement tasks.

Safety Precautions for Using Marble Parallel Gauges

1. Marble parallels are brittle and prone to damage from hard impacts or敲ings. Therefore, they should be handled gently during measurement or use to prevent heavy items like iron from hitting the working surface of the marble parallels. This helps avoid excessive dents, which can affect both their usability and appearance.

2. When not in use for a long period, the marble parallel gauge should be wiped with a specialized lubricant. If none is available, cooking oil can be used instead. To reuse it, simply dry it with a soft cloth. When the surface is stained, it's best to clean the spots with mild腐蚀剂 like lemon juice or vinegar. Avoid using soap or baking soda, as they can damage the marble's natural quality.

Common Deviations of Marble Parallel Gauges

Marble parallel gauges are high-precision precision measuring tools, with their production, processing, and inspection all completed in a controlled environment. After leaving the factory, factors such as external temperature and humidity fluctuations, excessive handling force during transportation, and vibrations during transit can all affect the precision of the marble parallel gauge. Of course, due to the anti-vibration treatment with foam boards and full-wood packaging used for marble parallel gauges, the impact on their precision during handling and transportation is significantly reduced, ensuring safe transport. However, to ensure optimal performance in a new environment, it is recommended to place the marble parallel gauge in a controlled environment for 2-3 days before use after transporting it to a new location.

Precision measurement for marble parallel gauges

Preparation Before Measurement

1. Requires two or more metrology inspectors.

2. Required equipment includes: electronic level, inspection bridge plate, precision flat plate, micrometer, and level blocks.

Marble parallel bar straightness measurement

Support the marble parallel bar with equal-height spacers at the standard support marks located 2L/9 from each end of the flat ruler. Choose an appropriate inspection bridge based on the work surface length of the marble parallel bar (usually 8 to 10 spans, with a span range of 50 to 500mm). Then, place the bridge on one end of the marble parallel bar and secure the level on the bridge. Gradually move the bridge from one end of the marble parallel bar to the other, reading the position readings from the level for each span; the difference between the highest and lowest readings is the straightness error of the work surface of the marble parallel bar. For any 200mm straightness error on the work surface, a bridge of 50mm or 100mm can be selected, and the inspection is performed within any 200mm as described above.

Parallelism inspection for marble parallel gauges

To check the parallelism of the working surfaces on both sides of the marble parallel ruler, and the parallelism between the working surface and the lower support surface, place the marble parallel ruler with the working surface (or the support foot support surface) as the base on a precision flat plate. Measure the height differences at no less than three points on its working surface using a micrometer with a graduation of 0.001mm mounted on a gauge stand. These height differences represent the parallelism error. In the absence of a suitable flat plate, it is permissible to place the side of the marble parallel ruler on a support surface, and measure the height differences using a lever micrometer with a graduation of 0.002mm or a tool equipped with a micrometer having a graduation of 0.002mm.

Natural deflection test of marble parallel bars

Place the parallel gauge supported by equal height blocks at the standard support marks located 2L/9 from each end of the flat ruler, and position it on the datum plane. Measure the reading at the midpoint of the working surface length using a dial gauge or comparator with a graduation of 0.001mm; then move the equal height blocks to the large support distance position (at both ends of the marble parallel gauge), stabilize for 10 minutes, and take the reading with the dial gauge or comparator; the difference between the two readings is the natural deflection of the marble parallel gauge.

Technical Requirements for Marble Parallel Gauges

1. Marble parallel rulers must not have cracks, dents, or loose tissue on the working surface, and should not have any wear marks or other defects that affect usage.

2. Permits natural, non-manufactured color stripes and spots to appear on the marble parallel gauge working surface.

3. Marble parallel gauges should not have cracks or large-scale tissue looseness on non-working surfaces. Dents, chipped edges, or scratches that appear are allowed to be repaired.

4. Marble parallel gauges should be made of fine-grained and dense stone. Suitable stone types for flat plates include "Jinan Green," "Taishan Green," and "Taishan Green and White Grain."

The physical properties of the stone should comply with

1) Compressive strength of 245 MPa or higher;

2) Bending strength of 22 kn/mm²; 3) Shore hardness greater than HS70

4) Moisture absorption rate less than 0.25%.

5. The working surface of the marble parallel gauge should be uniformly hard, with the Shore hardness of each part exceeding HS70.