Wing spread, wing height and boss size for cold-forged (Type A) and stamped (Type D) wing nuts, #4 to 3/4″. ASME B18.6.9.
A wing nut is a nut with two wings, turned by hand — no wrench or driver. ASME B18.6.9 sorts wing nuts by how they are made; this chart gives the two our sources both list: cold forged (Type A, solid wings) and stamped sheet metal (Type D). One thread size is made with more than one wing size, so match the wing spread of the nut in hand to a row.
| Size | Series | Threads per inch | Wing spread A | Wing height B | Wing thick. C | Between wings D | Boss dia. E | Boss height G |
|---|---|---|---|---|---|---|---|---|
| #4 | Heavy | — | .72 / .59 | .41 / .28 | .11 / .07 | .21 / .17 | .33 / .29 | .14 / .10 |
| #6 | Light | 32, 40 | .72 / .59 | .41 / .28 | .11 / .07 | .21 / .17 | .33 / .29 | .14 / .10 |
| #8 | Light | 32, 36 | .91 / .78 | .47 / .34 | .14 / .10 | .27 / .22 | .43 / .39 | .18 / .14 |
| #10 | Light | 24, 32 | .91 / .78 | .47 / .34 | .14 / .10 | .27 / .22 | .43 / .39 | .18 / .14 |
| #12 | Light | 24, 28 | 1.10 / .97 | .57 / .43 | .18 / .14 | .33 / .26 | .50 / .45 | .22 / .17 |
| 1/4″ | Light | 20, 28 | 1.10 / .97 | .57 / .43 | .18 / .14 | — / .26 | .50 / .45 | .22 / .17 |
| 5/16″ | Light | 18, 24 | 1.25 / 1.12 | .66 / .53 | .21 / .17 | .39 / .32 | .58 / .51 | .25 / .20 |
| 3/8″ | Light | 16, 24 | 1.44 / 1.31 | .79 / .65 | .24 / .20 | .48 / .42 | .70 / .64 | .30 / .26 |
| 7/16″ | Light | 14, 20 | 1.94 / 1.81 | 1.00 / .87 | .33 / .26 | .65 / .54 | .93 / .86 | .39 / .35 |
| 1/2″ | Light | 13, 20 | 1.94 / 1.81 | 1.00 / .87 | .33 / .26 | .65 / .54 | .93 / .86 | .39 / .35 |
| 5/8″ | Heavy | 11, 18 | 2.76 / 2.62 | 1.44 / 1.31 | .40 / .34 | .90 / .80 | 1.19 / 1.13 | .55 / .51 |
| 3/4″ | Heavy | 10, 16 | 2.76 / 2.62 | 1.44 / 1.31 | .40 / .34 | .90 / .80 | 1.19 / 1.13 | .55 / .51 |
| Size | Threads per inch | Wing spread A | Wing height B | Wing thick. C | Between wings D min | Boss dia. E | Boss height G min | Wall height H min | Stock thick. T |
|---|---|---|---|---|---|---|---|---|---|
| #8 | 32, 36 | .78 / .72 | .40 / .34 | .18 / .14 | .25 | .41 / .35 | .08 | .12 | .04 / .03 |
| #10 | 24, 32 | .91 / .85 | .47 / .41 | .21 / .17 | .34 | .53 / .47 | .10 | .12 | .04 / .03 |
| #12 | 24, 28 | 1.09 / 1.03 | .47 / .41 | .21 / .17 | .34 | .53 / .47 | .10 | .12 | .05 / .04 |
| 1/4″ | 20, 28 | 1.11 / 1.05 | .50 / .44 | .25 / .21 | .34 | .62 / .56 | .11 | .12 | .05 / .04 |
| 5/16″ | 18, 24 | 1.30 / 1.24 | .59 / .53 | .30 / .26 | .46 | .73 / .67 | .14 | .18 | .06 / .05 |
| 3/8″ | 16, 24 | 1.41 / 1.34 | .67 / .61 | .34 / .30 | .69 | .83 / .77 | .16 | .18 | .06 / .05 |
Good to know
Hand tight only. A wing nut is made to be turned by hand — use it where the nut comes off and goes back on, not where it needs a wrench.
Same thread, different wings. A 1/4″-20 wing nut can be cold forged or stamped, and the two have different wing spreads — measure the nut you have against the table. Hex nuts are on the hex nut chart.
Quick answers
- What is a wing nut?
- A nut with two wings that is turned by hand, with no wrench or driver. Wing nuts are covered by ASME B18.6.9.
- How big is a 1/4-20 wing nut?
- A cold-forged (Type A) 1/4″ wing nut, light series, has a wing spread of .97″ to 1.10″; a stamped (Type D) one, 1.05″ to 1.11″.
- How wide is a 3/8 wing nut?
- A cold-forged (Type A) 3/8″ wing nut, light series, spreads 1.31″ to 1.44″ across the wings.
- What is the difference between a forged and a stamped wing nut?
- A cold-forged (Type A) wing nut is solid; a stamped (Type D) wing nut is pressed from sheet metal. The two are made in different wing sizes for the same thread.
- Do you need a wrench for a wing nut?
- No — a wing nut is made to be turned by hand.