Finding Replacement Screws for Blue Robotics Products

Introduction

Blue Robotics uses a variety of screws in its components and assemblies. Because Blue Robotics does not sell individual screws except those that are included with retail packed products, this guide may be used as a reference of where to find replacement or additional screws for your project.

General Screw Characteristics

Generally, Blue Robotics uses metric size screws, which is the international standard and easier for customers outside of the United States to obtain. When metric size screws are impractical for Blue Robotics to obtain (usually thread forming), imperial size screws are used. A metric size dimension is given afterwards for customers to locate an equivalent.

Dimensions

Material

316 Stainless Steel screws are corrosion resistant in wet environments, nonmagnetic, and electrically conductive.

Aluminum screws are corrosion resistant, but weaker than stainless steel. Used when galvanic corrosion may be an issue.

Nylon screws are chemical and oil resistant, non-conductive, and lightweight. May expand when exposed to moisture.

Shorthand Description

Because the thread pitch is standardized for both metric and imperial screw sizes, it is often omitted. Screw descriptions are often written in shorthand as the following example:

• M3x12 = Screw thread diameter by thread length (mm)
• #4×0.5″ = Numbered screw diameter by thread length (inch)

For metric screws, if the thread pitch is not specified, you can assume the screw uses “coarse” pitch. A list of frequently used metric screws and their coarse pitch is provided below.

Locating Where Screws are Used in Blue Robotics Retail Packaging (RP)

Screws used in all Blue Robotics products can be found in two locations:

• 1. The “Contents” section of a product page.
• 2. The assembly guide steps for the relevant product.

Contents Section of a Product Page

The “Contents” section of each product page lists the loose screws that come with each product in its retail packaging. Screws already installed on a product assembly are not included with this list.

Assembly Guides

Screws used during the assembly or integration guides are called out during each step.

Locating Where Screws are Used in Blue Robotics Assembled Products (ASM)

For screws on pre-assembled products, the type and dimensions may be determined by following these steps:

• 1. Remove the screw from the assembly. Remember where it came from for reassembly. Taking pictures along the way may help.
• 2. Measure the thread diameter using a set of calipers.
• 3. Measure the thread length from the base of the head to the end of the end of the screw, unless otherwise specified from the screw characteristics.

Screw Sourcing

McMaster-Carr: McMaster-Carr is Blue Robotics’ preferred hardware store when prototyping. The company has one of the most complete collections of fasteners and other items for rapid project work.

Amazon: For smaller numbers of screws it may be more beneficial to find what you need on Amazon.

Screws Used in Blue Robotics Products

Socket Head Cap Screws

These standard socket head screws have a head height that matches the screw’s thread diameter.

Low Profile Socket Head Cap Screws

With half the head height of a standard socket head, they fit where space is limited, but their low profile makes their head weaker.

Button Head Cap Screws

These screws have rounded heads and are suitable for use on exterior surfaces to reduce snags.

Set Screws

Cup point set screws have a thin edge that digs into the contact surface for a secure hold on a wide range of surfaces.

Flat Head Screws

These screws are angled under the head to sit flush within countersunk holes. Length is measured from the top of the head.

Thread Forming Screws

These screws have a rounded head, excellent resistance to chemicals and salt water and may be mildly magnetic. They press tightly against formable plastic to resist loosening.