Thursday, September 27, 2012

Bolt

Bolt, commonly used with nuts, are the most widely used non-permanent fastening. The bolt head is usually hexagonal but may be square or round. The shank is screwed with a vee thread for all or parts of its length.
Materials
Most bolts are made of low or medium carbon steel by forging or machining and the threads are formed by cutting or rolling. Forged bolts are called black and machined bolts are called bright. They are also made in high tensile (HT bolts 8.8), alloy steel, stainless steel, brass and other metals.
  

             
TYPES OF BOLTS
1. Machine Bolt             4. Stove Bolt
2. Eye Bolt                       5. U bolt
3. Stud Bolt                      6. Carriage Bolt

TYPES OF SCREWS
1. Cap Screw
2. Machine Screw
3. Set Screw
4. Power Screw

THE AMERICAN NATIONAL SCREW THREAD

TYPES OF THREADS- 
1. UNC (Unified National Coarse Series) – is recommended for general use, where jar and vibration are not important factors, where dis-assembly of parts is frequent, and where tapped holes are in metals other than steel.

2. UNF (Unified National Fine Series) – is frequently used in automotive and aircraft work especially where jar and vibration (tending to loosen the nut) are present, where a fine adjustment is required with the use of a castle nut, and where a fine adjustment is required with the use of castle nut, and where tapped holes are in steel (avoid UNF in brittle materials)

3. UNEF (Unified National Extra Fine) – is particularly useful in aeronautical equipment, suitable where thin-walled materials is to be threaded, where fine adjustment are required, and where jar and vibration are excessive. Screws with these threads are likely to be made of heat treated alloy steel.

4. 8UN (Unified 8 – thread series) – is used on bolt for high-pressure pipe flanges, cylinder-head studs, etc. These are several constant pitch series, the 12 UN, 16 UN, and 20 UN. These threads are useful because in the regular coarse thread, the pitches continue to increase with size and it becomes increasingly difficult to induce the desire initial tension in the bolt, so necessary for tight joint. Even for the 8 UN thread, impact wrenches or very large leverages are needed for tightening to stresses of the order of the yield strengths. 

EXTRA FINE 8-THREAD SERIES TABLE
EXTRA FINE SERIES (NEF AND UNEF)

8-THREAD SERIES (8 N and 8 UN)
(Primary Sizes)
Size
Basic Major Diameter, in.
Th./In. (tpi)
Minor Dia. Ext Th.
Stress Area AS sq. in.
Size
Minor Dia. Ext. Th.
Stress Area As sq. in
12
0.2160
32
0.1777
0.0270
1
0.8466
0.606
1/4
0.2500
32
0.2117
0.0379
1 1/8
0.9716
0.790
5/16
0.3125
32
0.2742
0.0625
1 ¼
1.0966
1.000
3/8
0.3750
32
0.3367
0.0932
1 3/8
1.2216
1.233
7/16
0.4375
28
0.3937
0.1274
1 1/2
1.3466
1.492
1/2
0.5000
28
0.4562
0.170
1 5/8
1.4716
1.78
9/16
0.5625
24
0.5114
0.214
1 3/4
1.5966
2.08
5/8
0.6250
24
0.5739
0.268
1 7/8
1.7216
2.41
11/16
0.6875
24
0.6364
0.329
2
1.8466
2.77
3/4
0.7500
20
0.6887
0.386
2 1/4
2.0966
3.56
13/16
0.8125
20
0.7512
0.458
2 1/2
2.3466
4.44
7/8
0.8750
20
0.8137
0.536
2 3/4
2.5966
5.43
15/16
0.9375
20
0.8762
0.620
3
2.8466
6.51
1
1.0000
20
0.9387
0.711
3 1/4
3.0966
7.6738
1 1/16
1.0625
18
0.9943
0.799
3 1/2
3.3466
8.96
1 1/8
1.1250
18
1.0568
0.901
3 3/4
3.5966
10.34
1 3/16
1.1875
18
1.1193
1.009
4
3.8466
11.81
1 1/4
1.2500
18
1.1818
1.123
4 1/4
4.0966
11.38
1 5/16
1.3125
18
1.2443
1.244
4 1/2
4.3466
15.1
1 3/8
1.3750
18
1.3068
1.370
4 3/4
4.5966
16.8
1 7/16
1.4375
18
1.3693
1.503
5
4.8466
18.7
1 1/2
1.5000
18
1.4318
1.64
5 1/4
5.0966
20.7
1 9/16
1.5625
18
1.4943
1.79
5 1/2
5.3466
22.7
1 5/8
1.6250
18
1.5568
1.94
5 3/4
5.5966
24.9
1 11/16
1.6875
18
1.6193
2.10
6
5.8466
27.1


HEX HEAD BOLT STANDARD DIMENSION (by American Society Of Mechanical Engineering)
Bolt Diameter
Body Diameter
      Max                 Min
Across Flat
Across Corner
        Max             Min
Height of Bolt
Length Tread 6 in. below
Length Tread 6 in. Above
¼
0.26
.237
7/16
.505
.484
11/64
.75
1.0
5/16
.324
.298
½
.577
.522
7/32
.88
1.13
3/8
.388
.360
9/16
.650
.62
¼
1.0
1.25
7/16
.452
.421
5/8
.722
.687
19/64
1.13
1.38
½
.515
.482
¾
.866
.826
11/32
1.25
1.50
5/8
.642
.605
15/16
1.083
1.033
27/64
1.50
1.75
¾
.768
.729
1 1/8
1.299
1.24
½
1.75
2.00
7/8
.895
.852
1 5/16
1.516
1.447
37.64
2.0
2.25
1
1.022
.976
1 ½
1.732
1.653
43/64
2.25
2.50
1 1/8
1.149
1.098
1 11/16
1.949
1.859
¾
2.50
2.75
1 ¼
1.277
1.223
1 7/8
2.165
2.066
27/32
2.75
3.00
1 3/8
1.404
1.345
2 1/16
1.949
1.859
29/32
3.00
3.25
1 ½
1.531
1.47
2 ¼
2.598
2.48
1
3.25
3.50
1 ¾
1.785
1.716
2 5/8
3.031
2.893
1 5/32
3.75
4.00
2
2.039
1.964
3
3.164
3.306
1 11/32
4.25
4.50
2 ¼
2.305
2.212
3 3/8
3.897
3.719
1 ½
4.75
5.00
2 ½
2.559
2.461
3 ¾
4.33
4.133
1 21/32
5.25
5.50
2 ¾
2.827
2.711
4 1/8
4.763
4.546
1 13/16
5.75
6.00
3
3.081
2.961
4 ½
5.196
4.959
2
6.25
6.50
3 ¼
3.335
3.21
4 7/8
5.629
5.372
2 3/16
6.75
7.0
3 ½
3.589
3.461
5 ¼
6.062
5.786
2 5/16
7.25
7.50
3 ¾
3.858
3.726
5 5/8
6.495
6.198
2 ½
7.75
8.00
4
4.111
3.975
6
6.928
6.612
2 11/16
8.25
8.50