Carriage Bolt

Machine Screw
Machine Screw
Hex Flange Nut
Hex Flange Nut

Carriage Bolt

Product name: Carriage Bolt
Head type: Round head
Material: Carbon Steel, Alloy Steel, Stainless Steel
Standard: ASME/ANSI B 18.5, JIS B1171,DIN603
Measurement system: INCH, Metric
Size: #10 -1”, M5-M20
Grade / Class: Gr.A,5,8; Class. 8.8, 10.9, 12.9
Thread: M, UNC, UNF
Finish: Black Oxide, Zinc Plated(Clear/Blue/Yellow/Black), H.D.G. Y.Z.P. Plain, Nickel, Chrome

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DIN 603

Carriage Bolt Image

Carriage Bolt Drawing

Carriage Bolt Description

Carriage bolt (also called coach bolt and round-head square-neck bolt is a form of bolt used to fasten metal to metal or metal to wood.

It is distinguished from other bolts by its shallow mushroom head and the fact that the cross-section of the shank, though circular for most of its length (as in other kinds of bolt), is square immediately beneath the head. This makes the bolt self-locking when it is placed through a square hole in a metal strap. This allows the fastener to be installed with only one tool, a spanner or wrench, working from one side. The head of a carriage bolt usually is a shallow dome. The shank has no threads; and its diameter equals the side of the square cross-section.

The carriage bolt was devised for use through an iron strengthening plate on either side of a wooden beam, the squared part of the bolt fitting into a square hole in the ironwork. It is common to use a carriage bolt to bare timber, the square section giving enough grip to prevent rotation.

The carriage bolt is used extensively in security fixings, such as locks and hinges, where the bolt must be removable from one side only. The smooth, domed head and square nut below prevent the carriage bolt from being unlocked from the insecure side.


1Can I get some samples? Do you have samples in stock?
We are honored to send samples for your test if we have on hand. If some products showing are out of stock, we can provide custom sample production service if you need.
2Can you custom for me?
Yes, OEM custom is our specialty, trial orders can be accepted.
3What about the lead time?
Mass production time needs 7-35 days according to your order quantity;
4May I have your catalog and price list?
Please send the detailed inquiry to us, such as the Dimensions, Quantity, Payment Terms, Transport method, etc. We will make the accurate quotation to you as soon as possible, and try to give you the biggest Discount.