## How long are the threads on a bolt?

US Standard Thread Length for Bolts

Bolt Diameter | Standard Thread Length (in.) * | |
---|---|---|

Bolts 6 inches and shorter | Bolts longer than 6 inches | |

3/4″ | 1-3/4″ | 2″ |

7/8″ | 2″ | 2-1/4″ |

1″ | 2-1/4″ | 2-1/2″ |

### What thread size is a 1/2 bolt?

Standard Thread Pitch Chart

Coarse Thread Series – UNC | Fine Thread Series – UNF | |
---|---|---|

Nominal Size and Threads Per In. | Basic Pitch Dia. | Nominal Size and Threads Per In. |

1⁄2 – 13 | 0.45 | 1⁄2 – 20 |

9⁄16 – 12 | 0.5084 | 9⁄16 – 18 |

5⁄8 – 11 | 0.566 | 5⁄8 – 18 |

**How deep is a thread on a bolt?**

Many studies have found that there is a simple rule of thumb for standard pitch fasteners. The depth of a fastener should be at least two times its nominal diameter. For example a 1/4in (0.25in) fastener should be threaded at least 1/2in (0.50in) deep.

**What is the length of thread?**

The axial distance through which the fully formed threads of both the nut and bolt are in contact is called the length of thread engagement.

## How long is M8 bolt?

Standard Thread Length for Bolts | Metric

Bolt Diameter | 125mm and Shorter | Longer Than 125mm |
---|---|---|

M6 | 18 | 24 |

M7 | 20 | 26 |

M8 | 22 | 28 |

M10 | 26 | 32 |

### What are standard screw lengths?

Lengths range from 1/4″ to 6″; 5″ or so is the longest typically found and larger screw sizes are offered in the longer lengths. Sizes less than 1″ are in 1/8″ increments; lengths from 1″ to 3″ are in 1/4″ steps; and screws longer than 3″ increase in length by 1/2″.

**How long does my bolt need to be?**

A typical rule of thumb . . . Use a bolt diameter that is 1.5 – 2.5 times (up to three times) the thickness of the thinner material you are bolting together.

**How long should bolts be?**

A good rule to follow is to always use the shortest standard length fastener that gives a minimum one thread protrusion. Small and/or short bolts come in 1/8- or 1/4-inch increments. As the fastener gets larger and longer the increments change to 1/2 inch….Industry Rule-of- Thumb.

Threads per Inch | Protrusion |
---|---|

7 | .286 |