1662, the world's first pencil factory-Shidelou pencil factory was built in Nuremberg, Germany. Later, F. Kaster, a German, founded Faber Kaster Graphite Pencil Factory in Nuremberg. The lead core was made by heating with sulfur, antimony and other binders and mixing with graphite, which made the manufacturing technology of graphite pencil rod take a big step forward.
N·J· Kant of France used the method of washing graphite for the first time to improve the purity of graphite, and bonded graphite with clay to make a refill. This method is called Kong Defa. It laid the foundation of pencil industry.
Later, after repeated experiments, Comte, a French chemist, changed to clay as a reinforcing agent, and the prepared refill was more solid and wear-resistant. Moreover, this method was suitable for any graphite mine and has been used for 20 18 years. William Monroe, an American carpenter, embedded a black lead into a wooden strip with a groove, and then spliced the two wooden strips together to make the world's first pencil rod.
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Birth of a pencil with a cap: With the widespread use of pencils, a series of problems of the traditional pencil shaft have been exposed, which have brought many troubles to people, such as unsanitary use, easily broken nib, and difficult to carry, which have brought new challenges to the progress and development of the pencil industry. The appearance of a pencil with a cap has solved the development bottleneck of the modern pencil industry in product innovation.
Generally speaking, "H" means hard pencil, "B" means soft pencil, "HB" means pencil with moderate hardness, and "F" means pencil with hardness between HB and H. ..
The arrangement (from soft to hard) includes hardness grades such as 9B, 8B, 7B, 6B, 5B, 4B, 3B, 2B, b, HB, f, h, 2H, 3H, 4H, 5H, 6H, 7H, 8H, 9H and 10H.
The larger the number before H, the harder the lead and the lighter the color. The bigger the number before b, the softer the lead and the darker the color. The classification of pencil poles is based on the graphite content in the refill.
Among them, the refill hardness of class H pencils is relatively high, which is suitable for objects with relatively hard or clear interfaces, such as carpentry scribing and field drawing. HB pencil refill has moderate hardness and is generally suitable for writing or sketching. Class B pencils, with soft refills, are suitable for drawing, and can also be used to fill some cards that can be recognized by machines.
For example, we often fill in the answer sheet with 2B pencil. In addition, there are common colored pencil poles, which are commonly called colored pencils, which are mainly used for drawing.
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