Tag: Hex Nut

Posted on

Hex Nut Grade Identification and Mechanical Properties

How strong are these nuts?  That’s what she said.  Seriously, what do those marks mean?  Should I order a hex nut with one dot or three dashes?  Here’s a cheat sheet with nut identifying marks, material grade and mechanical properties.


Grade
Identification
Marking		 Specification Material Nominal Size
In.		 Proof
Load
Stress
ksi		 Hardness
Rockwell		 See
Note
Min Max

No Mark		 ASTM A563 – Grade 0 Carbon Steel 1/4 thru 1-1/2 69 B55 C32 3,4
ASTM A563 – Grade A Carbon Steel 1/4 thru 1-1/2 90 B68 C32 3,4
ASTM A563 – Grade B Carbon Steel 1/4 thru 1 120 B69 C32 3,4
over 1 thru 1-1/2 105
ASTM A563 – Grade C Carbon Steel
May be Quenched
and Tampered		 1/4 thru 4 144 B78 C38 5
ASTM A563 – Grade C3 Atmospheric
Corrosion
Resistant Steel
May be Quenched
and Tampered		 1/4 thru 4 144 B78 C38 5,9
ASTM A563 – Grade D Carbon Steel
May be Quenched
and Tampered		 1/4 thru 4 150 B84 C38 6
ASTM A563 – Grade DH Carbon Steel
Quenched
and Tampered		 1/4 thru 4 175 C24 C38 6
ASTM A563 – Grade DH3 Atmospheric
Corrosion
Resistant Steel,
Quenched
and Tampered		 1/4 thru 4 175 C24 C38 5,9
ASTM A194 – Grade 1 Carbon Steel 1/4 thru 4 130 B70 — 7
ASTM A194 – Grade 2 Medium Carbon
Steel		 1/4 thru 4 150 159 352 7,8
ASTM A194 – Grade 2H Medium Carbon
Steel, Quenched
and Tempered		 1/4 thru 4 175 C24 C38 7
ASTM A194 – Grade 2HM Medium Carbon
Steel, Quenched
and Tempered		 1/4 thru 4 150 159 237 7,8
ASTM A194 – Grade 4 Medium Carbon
Alloy Steel,
Quenched
and Tempered		 1/4 thru 4 175 C24 C38 7
ASTM A194 – Grade 7 Medium Carbon
Alloy Steel,
Quenched
and Tempered		 1/4 thru 4 175 C24 C38 7
ASTM A194 – Grade 7M Medium Carbon
Alloy Steel,
Quenched
and Tempered		 1/4 thru 4 150 159 237 7
See Note 1,2 10
Posted on

Hex Nut Dimensions

There are lots of reasons you need to know hex nut dimensions.  You need to hex nut height to determine the best length of a fastener in a bolted assembly.  You need to know the size of the hex to make sure you have sufficient clearance for the nut itself, the washer and a wrench.


Size Across Flats* Height
Hex Nut Machine Screw Nut Hex Nut Jam Nut Nylock Nut Machine Screw Nut
0 – 5/32 – – – 3/64
1 – 5/32 – – – 3/64
2 – 3/16 – – 9/64 1/16
3 – 3/16 – – 9/64 1/16
4 – 1/4 – – 9/64 3/32
6 – 5/16 – – 11/64 7/64
8 – 11/32 – – 15/64 1/8
10 – 3/8 – – 15/64 1/8
12 – 7/16 – – 5/16 5/32
1/4 7/16 7/16 7/32 5/32 5/16 3/16
5/16 1/2 9/16 17/64 3/16 11/32 7/32
3/8 9/16 5/8 21/64 7/32 29/64 1/4
7/16 11/16 – 3/8 1/4 29/64 –
1/2 3/4 – 7/16 5/16 19/32 –
9/16 7/8 – 31/64 5/16 41/64 –
5/8 15/16 – 35/64 3/8 3/4 –
3/4 1-1/8 – 41/64 27/64 7/8 –
7/8 1-5/16 – 3/4 31/64 63/64 –
1 1-1/2 – 55/64 35/64 1-3/64 –
* This is also the size of wrench to use.