BigBoltNut’s ASME B1.1 Fasteners: Engineered for precision, strength, and compliance
High-performance ASME B1.1 (Unified Inch Screw Thread) fasteners are our speciality at BigBoltNut. Also known as ANSI B1.1, it uses inch modules as a basis. This standard defines unified screw thread shape, series, class, allowance, and tolerance.
Understanding ASME B1.1:
The ASME thread standard guarantees that industries can rely on compatible and precise screw threads, ensuring consistency and dependability in their applications.
Three main thread combinations are in ASME B1.1:- UN (Unified National): This applies to internal and external threading.
- Unified National Rounded Root: This thread profile resembles UN threads but has a rounded root shape to improve fatigue strength.
- UNJ: High-stress applications require increased fatigue strength, indicated by an expanded root radius.
Applications classify these thread shapes into series:
- Unified National Coarse: This thread type is similar to the ISO metric thread and is used in many generic applications.
- UNF (Unified National Fine): Increases tensile stress areas and is used in higher-thread-count applications.
The standard specifies mating thread tolerance and allowance with several fit classes:
- Class 1A/1B: Loose fit for easy installation, even with slight thread damage.
- Class 2A/2B: This class balances structural integrity and assembly simplicity, making it popular for general applications.
- Class 3A/3B: unsuitable for precision tolerance work.
BigBoltNut's ASME B1.1 Compliance:
BigBoltNut produces fasteners that meet the stringent requirements of ASME B1.1 thread dimensions. Our product line includes:
- Stud Bolts These come in fully threaded, double-ended, and reduced shank designs, made of stainless steel, carbon steel, and alloy steel grades 8.8, 10.9, 12.9, SS304, SS316, SS316L, SS316 S31, B7, L7, 8M, and B8, among others.
- Hex Bolt Head: Inch series ASME B18.2.1-compliant Hex head bolts and Hex cap screws.
- Nuts and washers: We make these parts as per our fasteners to guarantee ASME compliant.
Uses of ASME B1.1-compliant fasteners:
These standard inch unified screw steel thread fasteners are used extensively in various fields because of their reliability. Generally, the wind energy sector has extensively used them, as they provide proper fastening capabilities for wind turbine setups.
- Civil Engineering Works: Providing compatibility and interchangeability of threaded components in bulk construction work.
- Pipeline Installation: BigBoltnut offers such fastening solutions that are suitable for critical pipeline applications.
- Wastewater & Water Treatment Plants: Corrosion-resistant fasteners for hostile environments.
Why BigBoltnut?
Fasteners that match the ASME B1.1 dimensioned BigBoltnuts have the following advantages:
- Exchangeability: Component change is simple due to standardized dimensions
- Reliability: Tolerances and allowances in several situations provide consistent performance.
- Safety: Some types of thread designs offer better fatigue strength and diminished failure in critical applications.
Our in-house test facilities are available for mechanical and chemical tests, including tensile, impact, Rockwell, Brinell, and magnetic particle inspection that showcase your quality. We further test using Micro Vickers hardness testing and microscopic carburisation and decarburisation analysis.
This Standard specifies the thread form, series, class, allowance, tolerance, and designation for unified screw threads. (In order to emphasize that unified screw threads are based on inch modules, they may be denoted unified inch screw threads.) Several variations in thread form have been developed for unified threads; however, this Standard covers only UN, UNR, and UNJ thread forms.
The UNR thread form and UN thread form are identical except that the roots of the external threads are rounded with a radius of curvature between 0.108 and 0.144 times the pitch. The rounded root improves fatigue strength compared to the UN thread form.
The UNR thread designation standard was developed during the 1950s due to the request for fatigue-resistant safety- critical fasteners. Almost all externally threaded
fastener manufacturers produce UNR rolled threads rather than plain unified form threads.
• UNC – Unified National Coarse Thread - comparable with the ISO metric thread
• UNF – Unified National Fine Thread
• Female and Male UNC/UNF threads are both parallel
• The UNC/UNF flank angle is 60°
Unified threads comes in three different classes:
a ) for applications where a liberal tolerance is required to permit easy assembly even withslightly
nicked threads
b ) most commonly used class for general applications
c ) for applications where closeness of fit and/or accuracy of
thread elements are important
UNC threads according ANSI B1.1:
|
Major Diameter |
Threads per inch |
Major Diameter |
Tap Drill Size |
Pitch |
|
|
(in) |
(tpi) |
(in) |
(mm) |
(mm) |
(mm) |
|
#1 - 64 |
64 |
0.073 |
1.854 |
1.5 |
0.397 |
|
#2 - 56 |
56 |
0.086 |
2.184 |
1.8 |
0.453 |
|
#3 - 48 |
48 |
0.099 |
2.515 |
2.1 |
0.529 |
|
#4 - 40 |
40 |
0.112 |
2.845 |
2.35 |
0.635 |
|
#5 - 40 |
40 |
0.125 |
3.175 |
2.65 |
0.635 |
|
#6 - 32 |
32 |
0.138 |
3.505 |
2.85 |
0.794 |
|
#8 - 32 |
32 |
0.164 |
4.166 |
3.5 |
0.794 |
|
#10 - 24 |
24 |
0.19 |
4.826 |
4 |
1.058 |
|
#12 - 24 |
24 |
0.216 |
5.486 |
4.65 |
1.058 |
|
1/4" - 20 |
20 |
0.25 |
6.35 |
5.35 |
1.27 |
|
5/16" - 18 |
18 |
0.313 |
7.938 |
6.8 |
1.411 |
|
3/8" - 16 |
16 |
0.375 |
9.525 |
8.25 |
1.587 |
|
7/16" - 14 |
14 |
0.438 |
11.112 |
9.65 |
1.814 |
|
1/2" - 13 |
13 |
0.5 |
12.7 |
11.15 |
1.954 |
|
9/16" - 12 |
12 |
0.563 |
14.288 |
12.6 |
2.117 |
|
5/8" - 11 |
11 |
0.625 |
15.875 |
14.05 |
2.309 |
|
3/4" - 10 |
10 |
0.75 |
19.05 |
17 |
2.54 |
|
7/8" - 9 |
9 |
0.875 |
22.225 |
20 |
2.822 |
|
1" - 8 |
8 |
1 |
25.4 |
22.85 |
3.175 |
|
1 1/8" - 7 |
7 |
1.125 |
28.575 |
25.65 |
3.628 |
|
1 1/4" - 7 |
7 |
1.25 |
31.75 |
28.85 |
3.628 |
|
1 3/8" - 6 |
6 |
1.375 |
34.925 |
31.55 |
4.233 |
|
1 1/2" - 6 |
6 |
1.5 |
38.1 |
34.7 |
4.233 |
|
1 3/4" - 5 |
5 |
1.75 |
44.45 |
40.4 |
5.08 |
|
2" - 4 1/2 |
4 1/2 |
2 |
50.8 |
46.3 |
5.644 |
|
2 1/4" - 4 1/2 |
4 1/2 |
2.25 |
57.15 |
52.65 |
5.644 |
|
2 1/2" - 4 |
4 |
2.5 |
63.5 |
58.5 |
6.35 |
|
2 3/4" - 4 |
4 |
2.75 |
69.85 |
64.75 |
6.35 |
|
3" - 4 |
4 |
3 |
76.2 |
71.1 |
6.35 |
|
3 1/4" - 4 |
4 |
3.25 |
82.55 |
77.45 |
6.35 |
|
3 1/2" - 4 |
4 |
3.5 |
88.9 |
83.8 |
6.35 |
|
3 3/4" - 4 |
4 |
3.75 |
95.25 |
90.15 |
6.35 |
|
4" - 4 |
4 |
4 |
101.6 |
96.5 |
6.35 |
Example - Typical designation of an UNC thread
• 1/4” x 20 UNC
UNF threads ANSI B1.1:
|
Major Diameter |
Threads per inch |
Major Diameter |
Tap Drill Size |
Pitch |
|
|
(in) |
(tpi) |
(in) |
(mm) |
(mm) |
(mm) |
|
#0 - 80 |
80 |
0.06 |
1.524 |
1.25 |
0.317 |
|
#1 - 72 |
72 |
0.073 |
1.854 |
1.55 |
0.353 |
|
#2 - 64 |
64 |
0.086 |
2.184 |
1.9 |
0.397 |
|
#3 - 56 |
56 |
0.099 |
2.515 |
2.15 |
0.453 |
|
#4 - 48 |
48 |
0.112 |
2.845 |
2.4 |
0.529 |
|
#5 - 44 |
44 |
0.125 |
3.175 |
2.7 |
0.577 |
|
#6 - 40 |
40 |
0.138 |
3.505 |
2.95 |
0.635 |
|
#8 - 36 |
36 |
0.164 |
4.166 |
3.5 |
0.705 |
|
#10 - 32 |
32 |
0.19 |
4.826 |
4.1 |
0.794 |
|
#12 - 28 |
28 |
0.216 |
5.486 |
4.7 |
0.907 |
|
1/4" - 28 |
28 |
0.25 |
6.35 |
5.5 |
0.907 |
|
5/16" - 24 |
24 |
0.313 |
7.938 |
6.9 |
1.058 |
|
3/8" - 24 |
24 |
0.375 |
9.525 |
8.5 |
1.058 |
|
7/16" - 20 |
20 |
0.438 |
11.112 |
9.9 |
1.27 |
|
1/2" - 20 |
20 |
0.5 |
12.7 |
11.5 |
1.27 |
|
9/16" - 18 |
18 |
0.563 |
14.288 |
12.9 |
1.411 |
|
5/8" - 18 |
18 |
0.625 |
15.875 |
14.5 |
1.411 |
|
3/4" - 16 |
16 |
0.75 |
19.05 |
17.5 |
1.587 |
|
7/8" - 14 |
14 |
0.875 |
22.225 |
20.4 |
1.814 |
|
1" - 12 |
12 |
1 |
25.4 |
23.25 |
2.117 |
|
1 1/8" - 12 |
12 |
1.125 |
28.575 |
26.5 |
2.117 |
|
1 1/4" - 12 |
12 |
1.25 |
31.75 |
29.5 |
2.117 |
|
1 3/8" - 12 |
12 |
1.375 |
34.925 |
32.75 |
2.117 |
|
1 1/2" - 12 |
12 |
1.5 |
38.1 |
36 |
2.117 |
Example - Typical designation of an UNF thread
• 1/2” x 20 UNF
Contact us today for high-quality and industrial-standard fasteners.