Fasteners

Introduction

Standardizing all your fasteners is the best way to make an easy and efficient R&D workflow. In our case, we primarily use M3-0.5 machine screws, the best balance between size and strength for the relatively small scale parts we build.

Standardizing Fasteners

There are many fasteners sizes around, and choosing a single one to standardize all your general applications to can be challenging. The most sure way in finding this is using various fasteners variations in your shop and taking note on the most useful ones. But this is a rather expensive and wasteful approach. The more analytical approach is as followed: first decide between metric or imperial screws. For those in the U.S., the benefit of imperial screws is its accessibility in various hardware stores. Depending on the scale and type of project, either metric or imperial would fit in better. Once that is decided upon, try the various sizes available for the scale of your projects. A good way to cross-reference is to look at what screws other people use for a project of similar scale to yours. Finally, look into the average load rating for each screw sizes. There will be a point where both the size of screw and its acceptable load limits are within the scope and scale of your projects. Even after this, remember, there are still varying factors that could heavily influence your fastener standardization process:

• Local availability

• Bulk costs

• Available materials

• Available head types

• Varying project standards

Machine Screw Head Type Guide

Head Type	Application
Socket Head	Recessed Cylindrical Sockets, Access panels, Load-bearing joints
Button Head	general purpose, lower profile exterior components, tamper resistant parts
Flat Head	Zero surface profile parts, total recessed panels, tamper resistant parts

Machine Screw Material Guide

Material	Application	Use for	Max Torque
304 Stainless Steel	Final part	Load bearing components, outdoor element exposed projects, etc.	25 ft-lb
Grade 2 Titanium	Final Part	Lightweight Structures, High Strength applications, etc.	20 ft-lb
Black Oxide Steel	Prototype/tooling	Cheap and fast proof of concepts and prototypes, tooling, jigs and fixtures.	25 ft-lb