Hex Cap Screws

Level I
Packager I

Revision Date: September 21, 2015

870

Hex Cap Screws

Description:

Hex head cap screws are a general purpose threaded fastener that are designed for inserting into a pre-tapped threaded hole or for use with hex nuts. They feature a thick, hexagonal head with a washer face under the head to provide an ample bearing surface for tightening with a wrench.

Material:

  • Steel
  • Stainless Steel
  • Brass

There are many other and they will be discussed at a later time.

Grades:

These are the most common grades of steel hex cap screws. For each of these grades there are different governing bodies that dictate the exact makeup of the fasteners. We will discuss some of these in further detail later.

307/Grade 2 grade2Markings
Grade 5 grade5Markings
Grade 8 grade8Markings

Markings:

Hex head cap screws will be marked by straight lined marks on the top of the head. These marks are known as hash marks. If there is any other markings on the head such as “JH”,  a lowercase “n”, or even a triangle this is not part of the grade markings. These markings are vendor markings and each vendor has its own way of marking their company information on the heads.
You will lean some hex head cap screws will not use hash marks to identify their grades. Sometimes they will stamp the head of the fastener with the specific specification. One example of this is A325.

Plating:

  • No Plating/Plain (Plain Steel)
  • Zinc
  • Yellow Chromate
  • Hot-Dipped Galvanized
  • Etc

How to measure:

 effective lgth bolt

 

 

First measure the diameter of the hex cap screw and then measure the effective length. The effective length of a hex cap screw is from the under side of the hex head to the end of the fastener.

Application:

The application for hex cap screws are almost endless. They may be used almost any where two or more objects need to be held together.

Abbreviation / Jargon:

  • Bolt
  • Hex Bolt
  • Hex Cap

Part Number Prefix:

  • 0HC* (Steel)
  • 1HC* (Stainless Steel)
  • 2HC* (Brass)

Style / Types:

  • Tap Bolts
  • Fine Thread, Coarse Thread and sometimes Medium Thread
  • Drilled in Head
  • Drilled in Thread

Larger Hex Caps, over 1 1/2 in diameter, are not technically a Hex Cap Screw they are bolts. This will be discussed in further detail later