Tolerance and Why ±1/32" Matters

"Measure twice, cut once" 

 

 What Is Tolerance? 

 Tolerance defines how far a part can deviate from its intended dimension while still working correctly. 

 Example: 

 

 10.000" ± 1/32" 

 This means the part can be slightly larger or smaller and still be acceptable 

 

 

 Why ±1/32" Matters in FRC 

 A tolerance of 1/32 inch (0.031") may seem small, but in robotics it can: 

 

 Prevent holes from lining up correctly 

 Cause shafts or bearings to bind 

 Create misalignment in drivetrains or elevators 

 Stack into larger errors across assemblies 

 

 Small errors add up when multiple parts depend on each other. 

 

 When Tight Tolerances Are Needed 

 Tight tolerances (like ±1/32") are important when: 

 

 Aligning bearing holes 

 Mounting shafts or gears 

 Building drivetrain frames 

 Connecting pre-cut or CAD-matched parts 

 

 

 When Loose Tolerances Are Acceptable 

 Looser tolerances are acceptable when: 

 

 Mounting non-critical brackets 

 Creating sensor mounts with adjustment 

 Working with slots or oversized holes 

 Designing parts that need adjustability 

 

 

 Best Practice 

 

 Measure twice before cutting or drilling 

 Use the same datum for all features 

 Center punch hole locations before drilling 

 Drill pilot holes before final sizing when precision is critical 

 

 

 Key Idea 

 Tolerance is not just a number—it is what determines whether parts fit together correctly or create assembly problems. In FRC, ±1/32" can be the difference between a smooth assembly and a misaligned mechanism.