在GB1017、HB1—218等技术条件标准中,均指明用界限卡规测量各种规格的90°和120°沉头螺栓、螺钉、铆钉的钉头高度。我们认为这样的界限卡规有如下缺点:精度高,制造困难;因受不同长度的限制,品种数量多,使用亦不方便。因而,我们对这种界限卡规及测量方法进行了改进,见下图。 In the GB1017, HB1-218 and other technical standards, are specified with a limit card gauge measuring a variety of 90 ° and 120 ° countersunk head bolts, screws, rivets head height. We think such limits card regulation has the following disadvantages: high precision, difficult to manufacture; due to different length restrictions, the number of varieties, use is not convenient. As a result, we have improved this gauge gauge and measurement method as shown below.