ASME B 18.6.3 Hex Head Screws- Plain (Unslotted) and Slotted Regular and Large (2024); is a technical standard developed by the American Society of Mechanical Engineers (ASME) that specifies the complete dimensional requirements, mechanical properties, test methods, and performance criteria for Hex Head Machine Screws.
This standard serves as the primary governing document in the United States and is widely referenced internationally for the design, procurement, and inspection of these fundamental fasteners.
Dimensions of ASME B18.6.3 Hex Head Screws Plain and Slotted Regular and Large
| Thread Size (d) | 1# | 2# | 3# | 4# | 5# | 6# | 8# | 10# | 12# | 1/4 | 5/16 | 3/8 | 7/16 | 1/2 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| d | Nominal Size | 0.0730 | 0.0860 | 0.0990 | 0.1120 | 0.1250 | 0.1380 | 0.1640 | 0.1900 | 0.2160 | 0.2500 | 0.3125 | 0.3750 | 0.4375 | 0.5000 |
| PP | 64 | 56 | 48 | 40 | 40 | 32 | 32 | 24 | 24 | 20 | 18 | 16 | 14 | 13 | |
| S1 Regular Head | max | 0.125 | 0.125 | 0.188 | 0.188 | 0.188 | 0.250 | 0.250 | 0.312 | 0.312 | 0.375 | 0.500 | 0.562 | 0.625 | 0.750 |
| min | 0.120 | 0.120 | 0.181 | 0.181 | 0.181 | 0.244 | 0.244 | 0.305 | 0.305 | 0.367 | 0.489 | 0.551 | 0.610 | 0.735 | |
| S2 Large Head | max | / | / | / | 0.219 | 0.250 | / | 0.312 | / | 0.375 | 0.438 | / | / | / | / |
| min | / | / | / | 0.213 | 0.244 | / | 0.305 | / | 0.367 | 0.428 | / | / | / | / | |
| e1 Regular Head | min | 0.134 | 0.134 | 0.202 | 0.202 | 0.202 | 0.272 | 0.272 | 0.340 | 0.340 | 0.409 | 0.545 | 0.614 | 0.682 | 0.820 |
| e2 Large Head | min | / | / | / | 0.238 | 0.272 | / | 0.340 | / | 0.409 | 0.477 | / | / | / | / |
| k | max | 0.044 | 0.050 | 0.055 | 0.060 | 0.070 | 0.093 | 0.110 | 0.120 | 0.155 | 0.190 | 0.230 | 0.295 | 0.348 | 0.400 |
| min | 0.036 | 0.040 | 0.044 | 0.049 | 0.058 | 0.080 | 0.096 | 0.105 | 0.139 | 0.172 | 0.208 | 0.270 | 0.321 | 0.367 | |
| n | max | / | / | / | 0.039 | 0.043 | 0.048 | 0.054 | 0.060 | 0.067 | 0.075 | 0.084 | 0.094 | / | / |
| min | / | / | / | 0.031 | 0.035 | 0.039 | 0.045 | 0.050 | 0.056 | 0.064 | 0.072 | 0.081 | / | / | |
| t | max | / | / | / | 0.036 | 0.042 | 0.046 | 0.066 | 0.072 | 0.093 | 0.101 | 0.122 | 0.156 | / | / |
| min | / | / | / | 0.025 | 0.030 | 0.033 | 0.052 | 0.057 | 0.077 | 0.083 | 0.100 | 0.131 | / | / | |
Technical Data provided by Fastener Planet