铸铁直角尺是一种基准量具,在机械行业的各部门被广泛应用,其寿命几乎可以认为是无限的,一般不需要以新换旧,磨损后刮研修复即可继续使用。而修理的前提是测量,若能准确掌握误差的分布情况,修理并不困难。再就是使用中的直角尺也需要做定期检验。目前大多数单位采用的测量方法,是在精密平板上,以高精度圆柱直角尺为基准,按光隙法作比较测量。本文则介绍不采用客观基准的自检法,精度较高且又简便易行。 Cast iron square is a benchmark measure, widely used in various sectors of the machinery industry, its life can almost be considered as an unlimited, generally do not need to replace the old, wear scratch repair can continue to use. The premise of repair is to measure, if we can accurately grasp the distribution of errors, repair is not difficult. Then there is the use of rectangular ruler also need to do regular testing. At present, most units adopt the measurement method, which is based on the precision flat plate, with the high precision cylindrical square as the benchmark, and compared with the light gap method. This article describes a self-test that does not use objective benchmarks, which is more accurate and simple.