Fasteners
Learn about what holds robots and the field together

Introduction to Fasteners
Fasteners are components used to mechanically join two or more parts together. In FRC, fasteners are essential for building rigid structures, attaching mechanisms, and allowing robots to be serviced and repaired efficiently. 

 Common types of fasteners include bolts, screws, rivets, nuts, and specialty locking hardware. Choosing the correct fastener affects strength, reliability, and how easily a robot can be maintained.

Bolt and Nut vs. Tapped Hole
Bolt and Nut 

 A bolt passes through two or more materials and is secured with a nut on the opposite side. 

 Advantages: 

 

 High strength connections 

 Easy to replace damaged hardware 

 Good for structural joints 

 

 Disadvantages: 

 

 Requires access to both sides 

 Can be slower to assemble 

 

 Tapped Hole 

 A tapped hole has internal threads cut into the material, allowing a screw to thread directly into the part. 

 Advantages: 

 

 Only one-side access needed 

 Clean and compact assemblies 

 

 Disadvantages: 

 

 Threads can strip if over-tightened 

 Not ideal for thin materials

Phillips Screws
Phillips screws are cross-head fasteners designed to allow controlled slipping (cam-out) under high torque. 

 Common driver sizes: 

 

 PH0: Very small electronics 

 PH1: Small screws and sensors 

 PH2: Most common hardware 

 PH3: Large fasteners 

 

 Correct Driver Fit 

 A proper driver: 

 

 Fully fills the screw head 

 Has minimal wobble 

 Engages all four contact points 

 

 Signs of Incorrect Fit 

 

 Stripping or rounding of the head 

 Slipping during tightening 

 Excessive force required 

 

 Using the correct driver size is one of the simplest ways to prevent hardware failure.

Washers
Washers are thin discs placed under fastener heads or nuts. 

 Flat Washers 

 

 Distribute load over a larger area 

 Prevent surface damage 

 

 Lock Washers 

 

 Help resist loosening from vibration 

 Less common in modern FRC than Nylock nuts 

 

 Fender Washers 

 

 Extra-large diameter 

 Used on thin materials like sheet metal or polycarbonate

Nylock Nuts
Nylock nuts contain a nylon insert that increases friction on the threads. 

 Advantages: 

 

 Resist loosening due to vibration 

 Reliable for moving mechanisms 

 Common in robotics assemblies 

 

 Limitations: 

 

 Nylon degrades under high heat 

 Reuse is limited (loses effectiveness over time)

Rivets
Rivets are permanent mechanical fasteners used to join materials, especially aluminum. 

 Common sizes: 

 

 1/8 inch 

 3/16 inch 

 

 Advantages 

 

 Lightweight 

 Fast installation 

 Strong in shear applications 

 

 Limitations 

 

 Not removable without drilling out 

 Requires correct grip range selection 

 

 Rivets are commonly used in chassis and sheet metal assemblies.

Threadlocker
When to Use 

 Use blue threadlocker when: 

 

 Fasteners are exposed to vibration 

 A joint must stay secure over time 

 A Nylock nut is not practical 

 

 

 Polycarbonate Warning 

 Do not use threadlocker in contact with polycarbonate (Lexan) or other stress-sensitive plastics. 

 

 It can cause cracking or “crazing” in the material 

 It can weaken plastic parts over time 

 

 Instead, use: 

 

 Nylock nuts 

 Proper mechanical fastening methods (washers, spacers, correct bolt length) 

 

 

 Application 

 

 Apply a small amount to metal threads only 

 Avoid excess that could spread onto plastic 

 Let the joint fully tighten before curing 

 

 

 Key Idea 

 Threadlocker is a backup for vibration resistance, not a replacement for proper fastener selection or good mechanical design.