未注公差尺寸的极限偏差（GB/T1800.1-1997）公称尺寸公 差 等 级公称尺寸公 差 等 级IT10IT11IT12IT13IT14IT10IT11IT12IT13IT14大于至单位：mm大于至单位：mm30.040.060.10.140.253154000.230.360.570.893.60360.0480.0750.120.180.304005000.250.40.630.974.006100.0580.090.150.220.365006300.280.440.71.14.410180.070.110.180.270.436308000.320.50.81.255.018300.0840.130.210.330.5280010000.360.560.91.45.630500.10.160.250.390.62100012500.420.661.051.656.650800.120.190.30.460.74125016000.50.781.251.957.8801200.140.220.350.540.87160020000.60.921.52.39.21201800.160.250.40.631.00200025000.71.11.752.811.01802500.1850.290.460.721.15250031500.861.352.13.313.52503150.210.320.520.811.30公称尺寸公 差 等 级公称尺寸公 差 等 级IT102IT112IT122IT132IT142IT102IT112IT122IT132IT142大于至单位：mm大于至单位：mm30.020.030.050.070.1253154000.1150.180.2850.4451.8360.0240.0370.060.090.154005000.1250.20.3150.4852.06100.0290.0450.0750.110.185006300.140.220.350.552.210180.0350.0550.090.1350.2156308000.160.250.40.6252.518300.0420.0650.1050.1650.2680010000.180.280.450.72.830500.050.080.1250.1950.31100012500.210.330.5250.8253.350800.060.0950.150.230.37125016000.250.390.6250.9753.9801200.070.110.1750.270.435160020000.300.460.751.154.61201800.080.1250.20.3150.5200025000.350.550.8751.45.51802500.0920.1450.230.360.575250031500.430.6751.051.656.752503150.1050.160.260.4050.65 未注公差尺寸的极限中差值(或基本偏差JSjs的 值)未注公差尺寸的（h）-中差值及基本偏差JSjs的 值（GB/T1800.1-1997）公称尺寸公 差 等 级IT10IT102IT11IT112IT12IT122IT13IT132IT14IT142大于至单位：mm30.980.020.970.030.950.050.930.070.8750.125360.9760.0240.9630.0370.940.060.910.090.850.156100.9710.0290.9550.0450.9250.0750.890.110.820.1810180.9650.0350.9450.0550.910.090.8650.1350.7850.21518300.9580.0420.9350.0650.8950.1050.8350.1650.740.2630500.950.050.920.080.8750.1250.8050.1950.690.3150800.940.060.9050.0950.850.150.770.230.630.37801200.930.070.890.110.8250.1750.730.270.5650.4351201800.920.080.8750.1250.80.20.6850.3150.50.51802500.9080.0920.8550.1450.770.230.640.360.4250.5752503150.8950.1050.840.160.740.260.5950.4050.350.653154000.8850.1150.820.180.7150.2850.5550.445-1.84005000.8750.1250.80.20.6850.3150.5150.485-25006300.860.140.780.220.650.350.450.55-2.26308000.840.160.750.250.60.40.3750.625-2.580010000.820.180.720.280.550.450.30.7-2.8100012500.790.210.670.330.4750.5250.1750.825-3.3125016000.750.250.610.390.3750.6250.0250.975-3.9160020000.70.30.540.460.250.75-1.15-4.6200025000.650.350.450.550.1250.875-1.4-5.5250031500.570.430.3250.675-1.05-1.65-6.75标准公差等级的选择公差等级应用条件说明应 用 举 例IT10应用条件与IT9相类似，但精度要求低于IT9电子仪器仪表中支架上的配合，打字机中铆合件的配合尺寸，闹钟机构中的中心管与前夹板，轴套与轴，手表中尺寸小于18mm时要求一般的未注公差尺寸及大于18mm要求较高的未注公差尺寸，发动机中油封档圈孔与曲轴皮带轮毂IT11配合精度要求较粗糙，装配后可能有较大的间隙，特别适用于要求间隙较大且有显著变动而不会引起危险的场合 机床上法兰盘止口与孔、滑块与滑移齿轮、凹槽等，农业机械、机车车箱部件及冲压加工的配合零件，钟表制造中不重要的零件，手表制造用的工具及设备中的未注公差尺寸，纺织机械中较粗糙的活动配合，印染机械中要求较低的配合，医疗器械中手术刀片的配合，磨床制造中的螺纹连接及粗糙的动连接，不作测量基准用的齿轮顶圆直径公差IT12配合精度要求很粗糙，装配后有很大的间隙非配合尺寸及工序间尺寸，发动机分离杆，手表制造中工艺装备的未注公差尺寸，计算机行业切削加工中未注公差尺寸的极限偏差，医疗器械中手术刀柄的配合，机床制造中扳手孔与扳手座的连接IT13应用条件与ITl2相类似非配合尺寸及工序间尺寸，计算机、打字机中切削加工零件及圆片孔、二孔中心距的未注公差尺寸IT14用于非配合尺寸及不包括在尺寸链中的尺寸机床、汽车、拖拉机、冶金矿山、石油化工、电机、电器、仪器、仪表、造船、航空、医疗器械、钟表、自行车、造纸、纺织机械等工业中未注公差尺寸的切削加工零件说明： 采用（GB/T1800.1-1997）规定尺寸的一般（未注）公差，应在图样标题栏附近或技术要求、技术文件（如企业标准）中注出标准号及公差等级代号。例如选用IT13等级时，标注为： 未注尺寸公差GB/T1800.1IT1未注公差线性尺寸的极限偏差数值表（GB/T1804-2000）公差等级尺 寸 分 段（单位：mm）0.53366303012012040040010001000200020004000精密f0.050.050.10.150.20.30.5中等m0.10.10.20.30.50.81.22粗糙c0.20.30.50.81.2234最粗v0.511.52.5468未注公差角度尺寸的极限偏差数值表（GB/T1804-2000）公差等级长 度 （单位：mm）10105050120120400400精密f13020105中等m粗糙c1301301510最粗v321