ISO METRIC PLUG, RING AND CALIPER THREAD GAUGES
Gauges for testing ISO metric screw threads
to BS 3643:1981, and BS 919:Pt 3:1968.
BS 3643 comprises two parts. Part 1 provides
information and data on the basic principles, and is based on
ISO 965/1 and ISO 965/3.
Part 2 tabulates diameters of coarse, constant and fine pitch series threads,
and is based on ISO 965/2.
BS 919: Pt3: 1968 contains the recommended
gauging system for checking ISO metric threads in accordance with BS 3643.
It is based on ISO 1502. The basic profile of the ISO threads is shown below.
BS 3643 Pt1 and Pt2 specifies the fundamental deviations and tolerances
for e.g. 5H, 6H, 6G and 7H for internal threads, and 4h, 6g, 6e, 8g for external
threads.
Generally 6H/6g are regarded as “medium fit”. The nut and bolt
deviations and tolerance zones are illustrated here.
Wherever practicable, external product threads should be tested by means of ring gauges as these provide a full functional test of all thread features: pitch, angle, thread form and size.
Gauges for testing products in the pre-plating condition can be supplied.
For internal threads class 6G may be used as a pre-plating condition for 6H
after plating. For external threads class 6e may be used as a pre-plating
condition for 6g after plating. Class 6g may also be used as a pre-plating
condition for 4h after plating. When ordering gauges for other plating conditions
it is helpful to advise either the effective diameters required, or the amount
of plating to be applied.
The regular checking of gauges in constant use is important. Plug gauges should be checked by direct measurement of the Major and Effective diameters, using a Floating Carriage Measuring Machine or similar specialised equipment. Ring gauges may be checked by direct measurement, or preferably by using Go check and Not Go Wear check plug gauges, as specified in BS 919: Pt3: 1968.
|
| Size | G0 | NOGO | 'E' | Go | NOGO | ROLLER | KNIFE |
| Class of fit | Class of fit | Class of fit | |||||
| 6H | 6H | 6H | 6g | 6g | ANY | ANY | |
|
Coarse Pitch |
|||||||
| M1.6X0.35 | 0330 | 0331 | 0330A | 1100 | 1101 | 1940 | 2140 |
| M1.8X0.35 | 0332 | 0333 | 0332A | 1102 | 1103 | 1941 | 2141 |
| M2.X0.40 | 0334 | 0335 | 0334A | 1104 | 1105 | 1942 | 2142 |
| M2.2X0.45 | 0336 | 0337 | 0336A | 1106 | 1107 | 1943 | 2143 |
| M2.5X0.45 | 0338 | 0339 | 0338A | 1108 | 1109 | 1944 | 2144 |
| M3.X0.50 | 0340 | 0341 | 0340A | 1110 | 1111 | 1945 | 2145 |
| M3.5X0.60 | 0342 | 0343 | 0342A | 1112 | 1113 | 1946 | 2146 |
| M4.X0.70 | 0344 | 0345 | 0344A | 1114 | 1115 | 1947 | 2147 |
| M4.5X0.75 | 0346 | 0347 | 0346A | 1116 | 1117 | 1948 | 2148 |
| M5.X0.80 | 0348 | 0349 | 0348A | 1118 | 1119 | 1949 | 2149 |
| M6.X1.00 | 0350 | 0351 | 0350A | 1121 | 1122 | 1950 | 2150 |
| M7.X1.00 | 0352 | 0353 | 0352A | 1123 | 1124 | 1951 | 2151 |
| M8.X1.25 | 0354 | 0355 | 0354A | 1126 | 1127 | 1952 | 2152 |
| M9.X1.25 | 0356 | 0357 | 0356A | 1128 | 1129 | 1953 | 2153 |
| M10.X1.50 | 0358 | 0359 | 0358A | 1130 | 1131 | 1954 | 2154 |
| M11.X1.50 | 0360 | 0361 | 0360A | 1132 | 1133 | 1955 | 2155 |
| M12.X1.75 | 0362 | 0363 | 0362A | 1134 | 1135 | 1956 | 2156 |
| M14.X2.00 | 0364 | 0365 | 0364A | 1136 | 1137 | 1957 | 2157 |
| M16.X2.00 | 0366 | 0367 | 0366A | 1138 | 1139 | 1958 | 2158 |
| M18.X2.50 | 0368 | 0369 | 0368A | 1140 | 1141 | 1959 | 2159 |
| M20.X2.50 | 0370 | 0371 | 0370A | 1143 | 1144 | 1960 | 2160 |
| M22.X2.50 | 0372 | 0373 | 0372A | 1146 | 1147 | 1961 | 2161 |
| M24.X3.00 | 0374 | 0375 | 0374A | 1149 | 1150 | 1962 | 2162 |
| M27.X3.00 | 0376 | 0377 | 0376A | 1152 | 1153 | 1963 | 2163 |
| M30.X3.50 | 0378 | 0379 | 0378A | 1155 | 1156 | 1964 | 2164 |
| M33.X3.50 | 0380 | 0381 | 0380A | 1158 | 1159 | 1965 | 2165 |
| M36.X4.00 | 0382 | 0383 | 0382A | 1161 | 1162 | 1966 | 2166 |
| M39.X4.00 | 0384 | 0385 | 0384A | 1164 | 1165 | 1967 | 2167 |
| M42.X4.50 | 0386 | 0387 | 0386A | 1167 | 1168 | 1968 | 2168 |
|
Fine Pitch |
|||||||
| M3.X0.35 | 0390 | 0391 | 0390A | 1180 | 1181 | 1970 | 2167 |
| M4.X0.50 | 0392 | 0393 | 0392A | 1182 | 1183 | 1971 | 2168 |
| M4.X0.75 | 0394 | 0395 | 0394A | 1184 | 1185 | 1972 | 2170 |
| M4.5X0.50 | 0396 | 0397 | 0396A | 1186 | 1187 | 1973 | 2191 |
| M5.X0.50 | 0398 | 0399 | 0398A | 1188 | 1189 | 1974 | 2172 |
| M6.X0.75 | 0400 | 0401 | 0400A | 1190 | 1191 | 1975 | 2173 |
| M7.X0.75 | 0402 | 0403 | 0402A | 1192 | 1193 | 1976 | 2174 |
| M8.X0.75 | 0404 | 0405 | 0404A | 1194 | 1195 | 1977 | 2175 |
| M8.X1.00 | 0406 | 0407 | 0406A | 1196 | 1197 | 1978 | 2176 |
| M9.X1.00 | 0408 | 0409 | 0408A | 1198 | 1199 | 1979 | 2177 |
| M10.X0.75 | 0448 | 0449 | 0448A | 1250 | - | - | 2178 |
| M10.X1.00 | 0410 | 0411 | 0410A | 1200 | 1201 | 1980 | 2179 |
| M10.X1.25 | 0412 | 0413 | 0412A | 1202 | 1203 | 1981 | - |
| M11.X1.00 | 0414 | 0415 | 0414A | 1204 | 1205 | 1982 | 2180 |
| M12.X1.00 | 0416 | 0417 | 0416A | 1206 | 1207 | 1983 | 2181 |
| M12.X1.25 | 0418 | 0419 | 0418A | 1208 | 1209 | 1984 | 2182 |
| M12.X1.50 | 0420 | 0421 | 0420A | 1210 | 1211 | 1985 | 2183 |
| M14.X1.00 | 0422 | 0423 | 0422A | 1212 | 1213 | 1986 | 2184 |
| M14.X1.50 | 0424 | 0425 | 0424A | 1214 | 1215 | 1987 | 2185 |
| M16.X1.00 | 0450 | 0451 | 0450A | 1253 | - | - | 2186 |
| M16.X1.50 | 0426 | 0427 | 0426A | 1216 | 1217 | 1988 | 2187 |
| M18.X1.50 | 0428 | 0429 | 0428A | 1218 | 1219 | 1989 | - |
| M18.X2.00 | 0430 | 0431 | 0430A | 1221 | 1222 | 1990 | 2188 |
| M20.X1.50 | 0432 | 0433 | 0432A | 1224 | 1225 | 1991 | 2189 |
| M20.X2.00 | 0434 | 0435 | 0434A | 1227 | 1229 | 1992 | 2190 |
| M22.X1.50 | 0452 | 0453 | 0452A | 1251 | - | - | 2191 |
| M22.X2.00 | 0436 | 0437 | 0436A | 1230 | 1231 | 1993 | 2192 |
| M24.X1.50 | 0454 | 0455 | 0454A | 1252 | 1252A | - | - |
| M24.X2.00 | 0438 | 0439 | 0438A | 1233 | 1234 | 1994 | 2194 |
