Pencil lead hardness sign, generally used "H" to indicate hard pencil, "B" means soft pencil, "HB" means soft and hard moderate pencil, "F" indicates hardness between HB and H pencil.
Arrange mode (from soft to hard) 9B, 8B, 7 B, 6B, 5 B, 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, 6H, 7H, 8H, 9H, 10H and other hardness grades. The larger the number in front of H, the harder it is to lead and the lighter the color. The larger the number in front of B, indicates that the softer the lead, the darker the color. The classification of pencil poles is divided according to the amount of graphite in the refill. Among them, Class H pencil, the core hardness is relatively high, suitable for the interface is relatively hard or clear objects, such as woodworking lines, field drawings, etc.; HB Pencil Refill hardness is moderate, suitable for general writing, or contour use; Class B pencils, the refill is relatively soft, suitable for painting, can also be used to fill some machine recognizable cards. For example, we often use 2B pencils to fill out answer cards.
In addition, it is common to color pencil poles, also known as color pencils, mainly used for painting.