毛主席教导我们:“在生产斗争和科学实验范围内,人类总是不断发展的,自然界也总是不断发展的,永会不会停止在一个水平上。”在200毫米宽砂轮试验的基础上,为了使宽砂轮磨削向前发展,我们在上海地区一些用户厂作了调查,在调查过程中,发现有些零件用200毫米宽砂轮磨削还不能满足要求,而要用更宽的宽砂轮进行磨削,如上海拖拉机齿轮厂有一个零件(见图一)必须用300毫米左右宽砂轮进行磨削。又如 Chairman Mao taught us: “In the struggle for production and within the limits of scientific experiments, mankind always develops continuously. Nature has always evolved and will never stop at a level.” Based on the 200 mm wide wheel test , In order to widen the grinding wheel to move forward, we have some users in Shanghai factory survey conducted during the investigation found that some parts with 200 mm wide wheel grinding can not meet the requirements, but to use a wider wide wheel Grinding, such as Shanghai tractor gear factory has a part (see Figure 1) must be about 300 mm wide grinding wheel. Another example