Frame tubing: Select a sturdy steel tubing, such as round or square tubing, for the main frame structure. The thickness of the tubing should be appropriate for the weight and speed of the intended usage.
Connector joints: Use metal connectors or gussets to join the tubing at various points in the frame.
Reinforcement plates: Add reinforcement plates or gussets to areas that experience high stress or loads.
Mounting brackets: Design and fabricate brackets to mount the sidecar to the motorcycle frame.
Suspension components: Incorporate suspension elements like springs and shock absorbers for a comfortable ride.
Brakes: Integrate a braking system for the sidecar wheel.
Welder:
A MIG (Metal Inert Gas) welder is generally recommended for this type of fabrication project. It provides precise control and produces clean, strong welds.
Ensure that you have the appropriate safety gear while welding, including gloves, protective clothing, and a welding mask.
It's important to have good welding skills to ensure the frame's integrity. If you're not experienced in welding, it may be advisable to consult a professional fabricator or welder to assist you in building the frame.