Thread Plug Gages
| BASIC THREAD DESIGNATION | DIMENSIONS IN MILLIMETERS | DIMENSIONS IN INCHES | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NOMINAL O.D. | PITCH | MAJOR DIA. | PITCH DIA. | MINOR DIA. | NOMINAL O.D. | THREADS PER INCH | MAJOR DIA. | PITCH DIA. | MINOR DIA. | |||||
| MIN. (MUST CLEAR) | MIN. GO | MAX. HI | MIN. | MAX. | MIN. (MUST CLEAR) | MIN. GO | MAX. HI | MIN. | MAX. | |||||
| M1.6x0.35 | 1.6 | 0.35 | 1.600 | 1.373 | 1.458 | 1.221 | 1.321 | .06299 | 72.57 | .06299 | .05406 | .05740 | .04807 | .05201 |
| M2x0.4 | 2.0 | 0.40 | 2.000 | 1.740 | 1.830 | 1.567 | 1.679 | .07874 | 63.50 | .07874 | .06850 | .07205 | .06169 | .06610 |
| M2.5x0.45 | 2.5 | 0.45 | 2.500 | 2.208 | 2.303 | 2.013 | 2.138 | .09843 | 56.44 | .09843 | .08693 | .09067 | .07925 | .08417 |
| M3x0.5 | 3.0 | 0.50 | 3.000 | 2.675 | 2.775 | 2.459 | 2.599 | .11811 | 50.80 | .11811 | .10531 | .10925 | .09681 | .10232 |
| M3.5x0.6 | 3.5 | 0.60 | 3.500 | 3.110 | 3.222 | 2.850 | 3.010 | .13780 | 42.33 | .13780 | .12244 | .12685 | .11220 | .11850 |
| M4x0.7 | 4.0 | 0.70 | 4.000 | 3.545 | 3.663 | 3.242 | 3.422 | .15748 | 36.29 | .15748 | .13957 | .14421 | .12764 | .13472 |
| M5x0.8 | 5.0 | 0.80 | 5.000 | 4.480 | 4.605 | 4.134 | 4.334 | .19685 | 31.75 | .19685 | .17638 | .18130 | .16276 | .17063 |
| M6x1 | 6.0 | 1.00 | 6.000 | 5.350 | 5.500 | 4.917 | 5.153 | .23622 | 25.40 | .23622 | .21063 | .21654 | .19358 | .20287 |
| M8x1.25 | 8.0 | 1.25 | 8.000 | 7.188 | 7.348 | 6.647 | 6.912 | .31496 | 20.32 | .31496 | .28299 | .28929 | .26169 | .27213 |
| M8x1 | 8.0 | 1.00 | 8.000 | 7.350 | 7.500 | 6.917 | 7.153 | .31496 | 25.40 | .31496 | .28937 | .29528 | .27232 | .28161 |
| M10x1.5 | 10.0 | 1.50 | 10.000 | 9.026 | 9.206 | 8.376 | 8.676 | .39370 | 16.93 | .39370 | .35535 | .36244 | .32976 | .34157 |
| M10x1.25 | 10.0 | 1.25 | 10.000 | 9.188 | 9.348 | 8.647 | 8.912 | .39370 | 20.32 | .39370 | .36173 | .36803 | .34043 | .35087 |
| M10x0.75 | 10.0 | 0.75 | 10.000 | 9.513 | 9.645 | 9.188 | 9.378 | .39370 | 33.87 | .39370 | .37453 | .37972 | .36173 | .36921 |
| M12x1.75 | 12.0 | 1.75 | 12.000 | 10.863 | 11.063 | 10.106 | 10.441 | .47244 | 14.51 | .47244 | .42768 | .43555 | .39787 | .41106 |
| M12x1.5 | 12.0 | 1.50 | 12.000 | 11.026 | 11.216 | 10.376 | 10.676 | .47244 | 16.93 | .47244 | .43409 | .44157 | .40850 | .42031 |
| M12x1.25 | 12.0 | 1.25 | 12.000 | 11.188 | 11.368 | 10.647 | 10.912 | .47244 | 20.32 | .47244 | .44047 | .44756 | .41917 | .42961 |
| M12x1 | 12.0 | 1.00 | 12.000 | 11.350 | 11.510 | 10.917 | 11.153 | .47244 | 25.40 | .47244 | .44685 | .45315 | .42980 | .43909 |
| M14x2 | 14.0 | 2.00 | 14.000 | 12.701 | 12.913 | 11.835 | 12.210 | .55118 | 12.70 | .55118 | .50004 | .50839 | .46594 | .48071 |
| M14x1.5 | 14.0 | 1.50 | 14.000 | 13.026 | 13.216 | 12.376 | 12.676 | .55118 | 16.93 | .55118 | .51283 | .52031 | .48724 | .49906 |
| M15x1 | 15.0 | 1.00 | 15.000 | 14.350 | 14.510 | 13.917 | 14.153 | .59055 | 25.40 | .59055 | .56496 | .57126 | .54791 | .55720 |
| M16x2 | 16.0 | 2.00 | 16.000 | 14.701 | 14.913 | 13.835 | 14.210 | .62992 | 12.70 | .62992 | .57878 | .58713 | .54469 | .55945 |
| M16x1.5 | 16.0 | 1.50 | 16.000 | 15.026 | 15.216 | 14.376 | 14.676 | .62992 | 16.93 | .62992 | .59157 | .59906 | .56598 | .57780 |
| M17x1 | 17.0 | 1.00 | 17.000 | 16.350 | 16.510 | 15.917 | 16.153 | .66929 | 25.40 | .66929 | .64370 | .65000 | .61886 | .63594 |
| M18x1.5 | 18.0 | 1.50 | 18.000 | 17.026 | 17.216 | 16.376 | 16.676 | .70866 | 16.93 | .70866 | .67031 | .67780 | .64472 | .65654 |
| M20x2.5 | 20.0 | 2.50 | 20.000 | 18.376 | 18.600 | 17.294 | 17.744 | .78740 | 10.16 | .78740 | .72346 | .73228 | .68087 | .69858 |
| M20x1.5 | 20.0 | 1.50 | 20.000 | 19.026 | 19.216 | 18.376 | 18.676 | .78740 | 16.93 | .78740 | .74906 | .75654 | .72346 | .73528 |
| M20x1 | 20.0 | 1.00 | 20.000 | 19.350 | 19.510 | 18.917 | 19.153 | .78740 | 25.40 | .78740 | .76181 | .76811 | .74476 | .75406 |
| M22x2.5 | 22.0 | 2.50 | 22.000 | 20.376 | 20.600 | 19.294 | 19.744 | .86614 | 10.16 | .86614 | .80220 | .81102 | .75961 | .77732 |
| M22x1.5 | 22.0 | 1.50 | 22.000 | 21.026 | 21.216 | 20.376 | 20.676 | .86614 | 16.93 | .86614 | .82780 | .83528 | .80220 | .81402 |
| M24x3 | 24.0 | 3.00 | 24.000 | 22.051 | 22.316 | 20.752 | 21.252 | .94488 | 8.47 | .94488 | .86815 | .87858 | .81701 | .83669 |
| M24x2 | 24.0 | 2.00 | 24.000 | 22.701 | 22.925 | 21.835 | 22.210 | .94488 | 12.70 | .94488 | .89374 | .90256 | .85965 | .87441 |
| M25x1.5 | 25.0 | 1.50 | 25.000 | 24.026 | 24.226 | 23.376 | 23.676 | .98425 | 16.93 | .98425 | .94591 | .95378 | .92031 | .93213 |
| M27x3 | 27.0 | 3.00 | 27.000 | 25.051 | 25.316 | 23.752 | 24.252 | 1.06299 | 8.47 | 1.06299 | .98626 | .99669 | .93512 | .95480 |
| M27x2 | 27.0 | 2.00 | 27.000 | 25.701 | 25.925 | 24.835 | 25.210 | 1.06299 | 12.70 | 1.06299 | 1.01185 | 1.02067 | .97776 | .99252 |
| M30x3.5 | 30.0 | 3.50 | 30.000 | 27.727 | 28.007 | 26.211 | 26.771 | 1.18110 | 7.26 | 1.18110 | 1.09161 | 1.10264 | 1.03193 | 1.05398 |
| M30x2 | 30.0 | 2.00 | 30.000 | 28.701 | 28.925 | 27.835 | 28.210 | 1.18110 | 12.70 | 1.18110 | 1.12996 | 1.13878 | 1.09587 | 1.11063 |
| M30x1.5 | 30.0 | 1.50 | 30.000 | 29.026 | 29.226 | 28.376 | 28.676 | 1.18110 | 16.93 | 1.18110 | 1.14276 | 1.15063 | 1.11717 | 1.12898 |
| M33x2 | 33.0 | 2.00 | 33.000 | 31.701 | 31.925 | 30.835 | 31.210 | 1.29921 | 12.70 | 1.29921 | 1.24807 | 1.25689 | 1.21398 | 1.22874 |
| M35x1.5 | 35.0 | 1.50 | 35.000 | 34.026 | 34.226 | 33.376 | 33.676 | 1.37795 | 16.93 | 1.37795 | 1.33961 | 1.34748 | 1.31402 | 1.32559 |
| M36x4 | 36.0 | 4.00 | 36.000 | 33.402 | 33.702 | 31.670 | 32.270 | 1.41732 | 6.35 | 1.41732 | 1.31504 | 1.32685 | 1.24685 | 1.27047 |
| M36x2 | 36.0 | 2.00 | 36.000 | 34.701 | 34.925 | 33.835 | 34.210 | 1.41732 | 12.70 | 1.41732 | 1.36618 | 1.37500 | 1.33209 | 1.34685 |
| M39x2 | 39.0 | 2.00 | 39.000 | 37.701 | 37.925 | 36.835 | 37.210 |
1.53543 |
12.70 | 1.53543 | 1.48429 | 1.49311 | 1.45020 | 1.46496 |
Frequently Asked Questions About This Pitch Diameter Chart
What is the significance of pitch diameter in thread measurement?
Pitch diameter is crucial as it determines the actual diameter at which the threads of the bolt and nut intersect, providing a baseline for whether a thread will fit correctly and perform its intended function.
How does the pitch diameter affect thread quality and performance?
A correct pitch diameter ensures that the threads engage properly, allowing for optimal strength, security, and durability of the threaded connection. It impacts load distribution and stress concentration on the threads.
Why are there different pitch diameters for the same nominal size?
Different thread profiles and standards (such as ISO, UN, etc.) have varying designations for pitch diameter to accommodate specific applications, tolerances, and materials, ensuring the best fit and performance across diverse engineering needs.
Can the pitch diameter chart be used for both inspection and manufacturing?
Yes, the thread plug gage pitch diameter chart is valuable for both inspection and manufacturing processes. It guides the manufacturing of thread plug gages and helps in inspecting the threaded parts to ensure they meet the specified tolerances.
How do I select the correct thread plug gage based on the chart?
Identify the nominal size and thread type of your component. Then, use the chart to find the corresponding pitch diameter for the specific tolerance class to select the correct thread plug gage.
