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import Bolt_label from ‘./bolt and nut labelled.jpg’ import Threads from ‘./Coarse_vs_fine_thread.png’ import button_head_10_32 from ‘./Button_head_10_32.jpg’ import nylock from ‘./nylock.jpg’ import Rivnuts from ‘./Rivnuts.jpg’ import Standard_nut from ‘./Standard_nut.jpg’

Bolts and Nuts

The Basics

A solid understanding of fasteners like bolts and nuts is crucial for building robust and reliable robots. This guide provides a quick reference for the common types of bolts and nuts used in Argos, how to identify them, and when to use each one.

What is a Bolt?

A bolt is a type of fastener with an external male thread. Bolts are used to assemble two or more unthreaded components, with the help of a nut.

What is a Nut?

A nut is a type of fastener with a threaded hole. Nuts are almost always used in conjunction with a mating bolt to fasten multiple parts together. Most nuts have six sides, so you can easily turn them with a wrench.

<img src={Bolt_label} width=”400”/>

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Bolt Naming Overview

Understanding how bolts are named is key to identifying them correctly. Here’s a breakdown of the components of a bolt’s name:

1. Diameter: How thick the bolt is.
   • Larger bolts (1/4” and up): Measured in fractions of an inch (e.g., 1/4”, 1/2”).
   • Smaller bolts (under 1/4”): Uses a number system from #0 to #12. A bigger number means a bigger bolt.
2. Threads Per Inch (TPI) & Thread Type: This tells you how many threads (grooves) are in one inch of the bolt’s length and indicates whether the thread is coarse or fine.
   • Coarse Thread (UNC): Fewer threads per inch (lower TPI). More common and easier to assemble.

   • Fine Thread (UNF): More threads per inch (higher TPI) for the same diameter. This provides a stronger hold and is better for applications with vibrations.

     <img src={Threads} width=”300”/>

3. Length: How long the bolt is, measured in inches from under the head to the tip for most common bolts.

Putting It Together

You’ll see sizes like “1/4-20 UNC x 1” or “1/4-28 UNF x 1”. Here’s what that means:

• “1/4” is the diameter.
• “-20 UNC” means 20 coarse threads per inch.
• “-28 UNF” means 28 fine threads per inch (for the same 1/4” diameter).
• “x 1” means it’s 1 inch long.

So, you primarily need to know Diameter - Threads Per Inch (which indicates Coarse/Fine) - Length. For the same diameter, a fine thread bolt will have a higher TPI number.

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Argos Bolt Quick Guide

Here’s a quick guide to selecting the right bolts for different applications on our team:

• Competition Robot? Use 10-32 Bolts.
  • These are #10 size bolts with 32 threads per inch (a fine thread).

  • Think: Fine threads for the Final robot – they hold tight!

    <img src={button_head_10_32} width=”200”/>

• Prototyping with 80/20? Use 1/4-20 Bolts.
  • These are 1/4 inch thick bolts with 20 threads per inch (a coarse thread).
  • Think: Coarse threads for construction and quick changes with 80/20.
• Exceptions
  • For the end of shafts, we use 1/4” bolts.

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Argos Nut Quick Refrence

We commonly use 3 types of nuts:

• Nyloc Nuts: A nyloc nut is a special kind of nut designed to resist loosening. It has a plastic ring inside that squeezes the bolt threads, making it harder for the nut to vibrate off.
  • You can identify them by the colored plastic ring inside one end of the nut.
  • Should not use Loctite with nyloc nuts, as it can damage the nylon insert.

  • Good to know: The bolt needs to go all the way through the plastic part for it to work correctly. They can be reused, but may lose some grip over time.

    <img src={nylock} width=”300”/>

• Rivnuts: These are threaded inserts that are installed into a material (like a piece of tubing) to provide a threaded hole. They look like a rivet with threads on the inside.

  • Should use Loctite to secure the bolt within the rivnut.

    <img src={Rivnuts} width=”200”/>

• Standard Nuts: These are the basic nuts with internal threads that screw onto a bolt. They typically have a hexagonal shape and no special inserts or features for locking.

  • Should use Loctite to prevent them from loosening due to vibration.

    <img src={Standard_nut} width=”200”/>

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