Description:

Low Carbon Steel Carriage: Round head bolt with a square neck under the head, and a unified thread pitch. Made from low or
medium carbon steel.
Hot-Dip Galvanized Steel Carriage: Carriage bolt made from low or medium carbon steel with a galvanic zinc finish applied.

 

Advantages:

Low Carbon Steel Carriage: The square neck is designed to keep the bolt from turning as a nut is tightened.
Hot-Dip Galvanized Steel Carriage: Same design advantages as a low carbon carriage bolt but with a thicker protective coating for outdoor use. Often used in outdoor furniture.

 

 

Carriage Bolt Square Neck

 

 

CARRIAGE BOLTS, SQUARE NECK ASME B18.5-1990
Nominal Size
or Basic Bolt
Diameter
E
A
H
O
p
Body Diameter
Head Diameter

Head Height

Square Width
Square Depth
Max
Min
Max
Min
Max
Min
Max
Min
Max
Min
•8
0.1640
0.173
0.157
0.328
0.298
0.102
0.083
0.169
0.155
0.108
0.078
10
0.1900
0.199
0.182
0.469
0.436
0.114
0.094
0.199
0.185
0.125
0.094
1/4
0.2500
0.260
0.237
0.594
0.563
0.145
0.125
0.260
0.245
0.156
0.125
5/16
0.3125
0.324
0.298
0.719
0.688
0.176
0.156
0.324
0.307
0.187
0.156
3/8
0.3750
0.388
0.360
0.844
0.782
0.208
0.188
0.388
0.368
0.219
0.188
7/16
0.4375
0.452
0.421
0.969
0.907
0.239
0.219
0.452
0.431
0.250
0.219
1/2
0.5000
0.515
0.483
1.094
1.032
0.270
0.250
0.515
0.492
0.281
0.250
5/8
0.6250
0.642
0.605
1.344
1.219
0.344
0.313
0.642
0.616
0.344
0.313
3/4
0.7500
0.768
0.729
1.594
1.469
0.406
0.375
0.768
0.741
0.406
0.375
Tolerance on Length
Nominal Bolt Size
Nominal Bolt Length
Up to 1 in.,
incl.		 Over 1 in. to
2-1/2 in., incl.		 Over 2-1/2 in.
to 4 in., incl.		 Over 4 in. to
6 in., incl.		 Over 6 in.
No. 8 thru 3/8
+0.02
-0.03
+0.02
-0.04
+0.04
-0.06
+0.06
-0.10
+0.10
-0.18
7/16 and 1/2
+0.02
-0.03
+0.04
-0.05
+0.06
-0.08
+0.08
-0.10
+0.12
-0.18
9/16 thru 3/4
+0.02
-0.03
+0.06
-0.08
+0.08
-0.10
+0.10
-0.10
+0.14
-0.18

 

‡Length of a carriage bolt is measured from the underhead bearing surface to the extreme

end of the bolt.
• ASME B18.5-1990 does not specify dimensions for the #8 diameter. Data listed for this size is independent of the ASME specification.

**Product standards require the manufacturer’s head marking to appear on the top of all bolts 1/4” diameter and larger. “X” represents one location such a marking may appear.

 

 

 

 

 

Email: E-mail Fastenerz.com

sales@fastenerz.com


Credit Accepted:
[IMAGE: Master card credit card] [IMAGE: Visa credit card]

 

 

 

  
 

Thank You!

February 24, 2004 All Rights Reserved © 1999-2004 Copyright
No part of this web document or its images may be used or copied

without written permission of Fastenerz.com
Violators will be prosecuted to the full extent of the law.