The 2x1 standard
The single most common FRC structural element is 2" x 1" aluminum tubing, usually pre-drilled in a repeating hole pattern. Bolting pieces of patterned tube together with gussets lets you build a strong, light, serviceable frame using only a saw and a hand drill.
Vendor systems
- REV MAXTube — extruded aluminum tubing in 2x1, 1x1, and 2x2 sizes, part of the REV ION build system. The 2x1 carries #10 clearance holes (0.196") on a 0.5" pitch on the 1" faces, and comes in solid, grid, and MAX Pattern (with MAXSpline cutouts every 2") configurations, plus variable wall thickness to tune strength-to-weight. It mates with MAXSpline brackets and a large ecosystem of REV gussets.
- WestCoast Products / VEXpro versa-frame — 2x1 and 1x1 punched tubing with matching gussets and bearing blocks, designed for West Coast drivetrains.
- AndyMark — tube stock, gussets, and the AM14U6 KitBot chassis.
Staying within one vendor's hole pattern means brackets, gussets, and bearing blocks line up without custom drilling.
Aluminum alloys
- 6061-T6 — the general-purpose alloy for tubing, plates, and brackets. Strong, light, weldable, and easy to machine. The default for most structure.
- 7075-T6 — stronger than 6061; used for highly loaded parts like hex shafts and some gears, but more expensive and harder to weld.
Plates and gussets
Flat aluminum plate (often 1/8" or 1/4") forms side plates, gearbox plates, and gussets. A CNC router is the typical way teams cut custom plates with bolt patterns that match their tube.
Why aluminum
Aluminum hits the FRC sweet spot of strength, low weight, machinability, and cost. Steel is stronger but heavy; titanium and carbon fiber are exotic and expensive. For a robot under a strict weight limit, aluminum tube plus selective use of plate is the workhorse.
Key takeaways
- 2x1 pre-drilled aluminum tube (REV MAXTube, WCP/VEXpro versa-frame) is the structural backbone of modern robots
- Staying in one vendor's hole pattern keeps gussets and bearing blocks aligned without custom drilling
- 6061-T6 is the general-purpose alloy; 7075-T6 is reserved for highly loaded parts like shafts
Lesson quiz
RequiredAnswer all 3 questions correctly to complete this lesson.
01.Why is 6061-T6 the most common aluminum alloy for FRC robot frames and tubing rather than the stronger 7075?
02.Why do FRC teams try to stay within a single vendor's tube hole pattern when building a frame?
03.REV MAXTube 2x1 tubing is designed with what hole pattern on its 1-inch faces?
Answer every question to submit.
All 47 lessons in Mechanical, Build & Pneumatics
- Not started:Mini-Project 1: A Single-Jointed Arm From Math to Motion
- Not started:Mini-Project 2: A Two-Stage Cascade Elevator
- Not started:Mini-Project 3: A Velocity-Controlled Flywheel Shooter
- Not started:Mini-Project 4: A Pivoting Roller Intake
- Not started:Mini-Project 5: Integrating a COTS Swerve Module
- Not started:Pneumatics Won't Fire: A Full Diagnostic Tree
- Not started:The Robot Won't Drive Straight (and Other Drivetrain Sins)
- Not started:Gearboxes That Grenade and Fasteners That Vibrate Loose
- Not started:Closed-Loop Mechanisms That Oscillate, Sag, or Stall
- Not started:Field-Ready Reliability: Inspection, Spares, and the Pit Checklist
- Not started:Characterizing Any Mechanism with SysId
- Not started:Simulation-Driven Design with WPILib Physics Models
- Not started:Motion Profiling and Superstructure Coordination
- Not started:Designing for Weight, Stiffness, and Manufacturability
- Not started:Case Studies: Learning From Open Alliance Robots