ASME B18.6.9 is the standard cited for wing nuts, type a, inch. This page sets out what the standard controls for this part, reproduces the dimensional table supplied against it, and notes the related designations referenced on drawings.
ASME B18.6.9 — Scope
The table below lists the dimensions catalogued for wing nuts, type a, inch under ASME B18.6.9. The scope of ASME B18.6.9 itself is not summarised here — where a figure matters, confirm it against the published document.
Tolerance & Product Grades
Product grade is a concept from dimensional fastener standards and does not apply to ASME B18.6.9. Tolerances for this part are the limits shown against each dimension in the table.
Dimensions Specified by ASME B18.6.9
| Size | Threads per inch | A (in) | B (in) | C (in) | D (in) | E (in) | G (in) | Reference standard |
|---|---|---|---|---|---|---|---|---|
| #3 | 48 | 0.655 | 0.345 | 0.09 | 0.19 | 0.31 | 0.12 | ASME B18.6.9 |
| #4 | 40 | 0.655 | 0.345 | 0.09 | 0.19 | 0.31 | 0.12 | ASME B18.6.9 |
| #5 | 40 | 0.655 | 0.345 | 0.09 | 0.19 | 0.31 | 0.12 | ASME B18.6.9 |
| #6 | 32 | 0.845 | 0.405 | 0.12 | 0.245 | 0.41 | 0.16 | ASME B18.6.9 |
| #8 | 32 | 0.845 | 0.405 | 0.12 | 0.245 | 0.41 | 0.16 | ASME B18.6.9 |
| #10 | 24 | 0.845 | 0.405 | 0.12 | 0.245 | 0.41 | 0.16 | ASME B18.6.9 |
| #12 | 24 | 1.035 | 0.5 | 0.16 | 0.295 | 0.475 | 0.195 | ASME B18.6.9 |
| 1/4" | 20 | 1.035 | 0.5 | 0.16 | 0.295 | 0.475 | 0.195 | ASME B18.6.9 |
| 5/16" | 18 | 1.185 | 0.595 | 0.19 | 0.355 | 0.545 | 0.225 | ASME B18.6.9 |
| 3/8" | 16 | 1.375 | 0.72 | 0.22 | 0.45 | 0.67 | 0.28 | ASME B18.6.9 |
| 7/16" | 14 | 1.875 | 0.935 | 0.295 | 0.595 | 0.895 | 0.37 | ASME B18.6.9 |
| 1/2" | 13 | 1.875 | 0.935 | 0.295 | 0.595 | 0.895 | 0.37 | ASME B18.6.9 |
| 9/16" | 12 | 2.69 | 1.375 | 0.37 | 0.85 | 1.16 | 0.53 | ASME B18.6.9 |
| 5/8" | 11 | 2.69 | 1.375 | 0.37 | 0.85 | 1.16 | 0.53 | ASME B18.6.9 |
| 3/4" | 10 | 2.69 | 1.375 | 0.37 | 0.85 | 1.16 | 0.53 | ASME B18.6.9 |
Companion Standards
A complete specification for wing nuts, type a, inch normally cites several documents: one for the geometry, one for the material or mechanical properties, and one for the finish. ASME B18.6.9 is one of them, not all of them.
When to Specify ASME B18.6.9
ASME B18.6.9 is the inch-based reference; for metric programs choose the ISO equivalent instead.
Custom manufacturing · Made to drawing
Need a nut to this standard in a non-standard size?
Parts built to ASME B18 6 9 are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

