CAIBI project benchmark: OpenBike Rev4
Prompt version 1.0

Help me build OpenBike Rev4 using the existing creator project at https://openbike.cc/download/. This is a CAIBI benchmark adaptation of the project build brief, not a claim about how the creator used AI.

Project context:
- An open wooden bicycle whose frame parts are CNC-cut locally, with additional printed parts and conventional bicycle components assembled into a usable physical vehicle.
- Build context: 21 mm birch plywood for the main fabricated wooden structure; 5 mm aluminium plate; TPU filament for printed parts; Carbon-fibre PLA filament as listed by the Rev4 source; Wood glue; BB86 press-fit bottom bracket; Single-speed crankset with 24 mm spindle and 50-tooth chainring; Chain and flat pedals; 1 1/8 inch steering/headset components; 20 inch front and coaster-brake rear wheels as specified by the current Rev4 source; 18-tooth sprocket and required fasteners.
- Where AI helps: Explain the source BOM and fabrication sequence, Help map source dimensions into CNC/CAM preparation, Compare reusable bicycle components with source requirements, Help reason through non-safety-critical customisation before cutting, Troubleshoot assembly observations against the documented geometry.
- Physical work: Source structurally suitable plywood, aluminium and bicycle components, Prepare and supervise CNC machining, 3D print the required parts, Inspect every machined and printed component, Assemble and align the frame, fork, steering and drivetrain, Set up and verify brakes and wheels, Make the final safety and road-use decision.
- Main limitation: A downloadable bicycle design is not proof of a safe finished bicycle. Steering fit, frame joints, material quality, wheel alignment, braking and every load-bearing interface must be verified on the real build. CAIBI has not road-tested Rev4 and does not infer roadworthiness from the files.

Read the source first. Use its published design, files, dimensions and parts as the baseline; do not redesign it unless a missing detail requires a clearly labelled proposal. If you cannot access a source or verify a revision, say so.

Provide one practical build package:
1. Design and files: explain the source design, link the original editable files, and identify missing files or modifications.
2. Parts and fabrication: give quantities, exact variants and compatibility, plus a cutting or printing list where applicable. Preserve source dimensions; flag anything unconfirmed.
3. UK and US purchasing: direct product links, checked dates, stock, pack sizes, taxes, delivery and regional costs. Mark unverifiable details as unknown; do not invent links, prices or availability.
4. Assembly: an ordered guide covering fabrication, fitting, wiring or software as applicable, setup, checks and troubleshooting.
5. Cost and time: separate parts, fabrication, delivery, hands-on time and machine time, with assumptions and exclusions.
6. Function and ease: a test plan for the project's stated purpose, likely difficulties, required skills and any corrections or limitations.

Keep source facts, your proposals and items needing physical verification distinct. An estimate is not a measured build result. Do not claim to have built or tested hardware. Include failed attempts and omissions. If a section does not apply, say why.

Use the source as accessed during this run and record its revision or access date. The prompt is fixed; the linked source can change.