卧式镗床、座标镗床工作部件(工作台、床鞍、主轴箱溜板、横梁等)的夹紧装置对座标定位精度和加工精度稳定性影响很大。苏联生产的座标镗床工作部件夹紧时的位移误差占座标定位总误差的10～30%(POCT 1809～72规定)。一些国家对座标镗床工作部件定位时的夹紧位移误差都作了相应 Horizontal boring machine, jig boring machine working parts (table, bed saddle, spindle box skid, beams, etc.) of the clamping device on the positioning accuracy and precision machining stability of great influence. The displacement error of the working boring parts of the coordinate boring machine manufactured by the Soviet Union accounts for 10% ~ 30% of the total error of the positioning (POCT 1809 ~ 72). In some countries, the error of clamping and displacement of the coordinate boring machine working part is corresponding