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- Unification. Bold type indicates products unified dimensionally with British and Canadian standards. Unification of fine thread products is limited to sizes 1 in. and under.
- Tops and Bearing Surface of Nuts. Nuts in sizes 5/8 in. nominal size and smaller shall be double chamfered. Larger size nuts shall be double chamfered or have washer faced bearing surface and chamfered top.
The diameter of chamfer circle on double chamfered nuts and diameter of washer face shall be within the limits of the maximum width across flats and 95 percent of the minimum width across flats.
The tops of washer faced nuts shall be flat and the diameter of chamfer circle shall be equal to the maximum width across flats within a tolerance of minus 15 percent. The length of chamfer at hex corners shall be from 5 to 15 percent of the basic thread diameter. The surface of chamfer may be slightly convex or rounded.
Bearing surface shall be flat and perpendicular to the axis of the threaded hole within the FIM limits specified for the respective strength level. - Width Across Flats. Maximum width across flats shall not be exceeded. No transverse section through the nut between 25 and 75 percent of the actual nut thickness as measured from the bearing surface shall be less than the minimum width across flats. For milled-from-bar nuts, see statement in General Data pertaining to the nominal bar size to be used.
- Corner Fill. A rounding or lack of fill at junction of hex corners with chamfer shall be permissible provided the minimum width across corners is within specified limits at and beyond a distance equal to 17.5 percent of the basic thread diameter from the chamfered faces.
Unit of Measure
Specifications
Product |
N/A Nuts |
Unit of Measure |
N/A English |
Nominal Size or Basic Major Dia. of Thread |
N/A 1-1/2 in |
Nominal Size or Basic Major Dia. of Thread (Decimal) |
N/A 1.5000 in |
Basic Width Across Flats (F) |
N/A 2-1/4 in |
Max. Width Across Flats (F) |
N/A 2.250 in |
Min. Width Across Flats (F) |
N/A 2.175 in |
Max. Width Across Corners (G) |
N/A 2.598 in |
Min. Width Across Corners (G) |
N/A 2.480 in |
Basic Thickness (H) |
N/A 1-1/2 in |
Max. Thickness (H) |
N/A 1.526 in |
Min. Thickness (H) |
N/A 1.474 in |
Max. Unslotted Thickness (T) |
N/A 1.08 in |
Min. Unslotted Thickness (T) |
N/A 1.04 in |
Max. Width of Slot (S) |
N/A 0.46 in |
Min. Width of Slot (S) |
N/A 0.37 in |
