一般是螺栓的直径乘以1.5倍就是呆口、梅花的尺寸。内六角扳手一般是螺栓的直径减去2。所有的扳手，包括开口扳手、内六角扳手、梅花扳手、套筒扳手等，其尺寸都是指螺栓头部对边的宽度尺寸，而螺栓的规格是指螺纹的公称直径。例如，M10的外六角螺栓，其对边宽度为16mm（参见国标GB/5780-86，设计手册上都有），就选用16的开口扳手或梅花扳手。又如GB/70－85内六角螺栓，M10的内六角螺栓的对边尺寸为8mm，则选用8mm的内六角扳手。
Generally, the diameter of the bolt multiplied by 1.5 times is the size of the socket and plum blossom. Allen wrench is generally the diameter of the bolt minus 2. All wrenches, including open-ended wrench, Allen wrench, box wrench, socket wrench, etc., refer to the width of the opposite side of the bolt head, and the specification of the bolt refers to the nominal diameter of the thread. For example, if the width of opposite side of M10 outer hexagon bolt is 16mm (see GB / 5780-86, which is available in the design manual), 16 open-ended wrench or ring wrench shall be selected. Another example is GB / 70-85 hexagon socket bolt. If the opposite side size of M10 hexagon socket bolt is 8mm, 8mm hexagon socket wrench shall be selected.
随着经济的发展，我国很多企业进口了大量的通用机械（如：水泵、阀门等）和设备，而这些设备的制造多采用英制标准，给企业日常维护时工器具的配备和选用带来了一定的麻烦，尤其是螺栓所对应的扳手。在此，笔者整理提供了一份扳手计算的资料供大家参考。
With the development of economy, many Chinese enterprises have imported a large number of general machinery (such as water pumps, valves, etc.) and equipment, and the manufacturing of these equipment mostly adopts British standards, which brings some trouble to the allocation and selection of tools and instruments during daily maintenance, especially the wrench corresponding to the bolt. Here, the author arranges and provides a wrench calculation data for your reference.
1、计算标准螺栓螺母尺寸（扳手尺寸）的经验公式（采用分数形式）：
1. Empirical formula for calculating standard bolt and nut size (wrench size) (in fractional form):
标准螺栓螺母尺寸（扳手尺寸）=（螺栓螺纹尺寸分子×3）÷（螺栓螺纹尺寸分子×2）
Standard bolt and nut size (wrench size) = (bolt thread size) × 3) ÷ (numerator of bolt thread size) × 2）
例如：1/2英寸螺纹的标准螺栓对应的扳手尺寸=（1×3）÷（2×2）英寸=3/4英寸
For example: wrench size corresponding to standard bolt with 1 / 2 inch thread = (1) × 3）÷（2 × 2) Inch = 3 / 4 inch
2、计算加重螺栓螺母尺寸（扳手尺寸）的经验公式（采用分数形式）：
2. Empirical formula for calculating the size of weighted bolt and nut (wrench size) (in fractional form):
加重螺栓螺母尺寸（扳手尺寸）=标准螺栓螺母尺寸1/8
Weighted bolt and nut size (wrench size) = standard bolt and nut size 1 / 8
例如：1/2英寸螺纹的加重螺栓对应的扳手尺寸=（1×3）÷（2×2）英寸1/8=7/8英寸
For example: wrench size corresponding to weighting bolt with 1 / 2 inch thread = (1) × 3）÷（2 × 2) Inch 1 / 8 = 7 / 8 inch
以下给出了少部分螺栓对应扳手的列表，敬请使用。螺栓螺纹
The list of wrenches corresponding to a few bolts is given below. Please use it. Bolt thread
尺寸标准螺栓螺母尺寸（扳手尺寸）加重螺栓螺母尺寸（扳手尺寸）内六角螺栓螺纹
Size standard bolt nut size (wrench size) weighted bolt nut size (wrench size) hexagon socket bolt thread
