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- As mentioned before, VR3 is our place for mitering and acquiring all tubing. That being said, I won’t go into much detail, as they have everything documented themselves. Follow their guides and you will be fine, they are very accommodating and friendly.
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Frame Jigging
- In short, a frame jig is essentially an assembly of parts that properly support the tubing/suspension tabs/any welded part during the welding process.
- A lot of the writing composed in this section is from some of the lovely Combustion and Election Electric members who have helped guide and educate me and my members on the jigging process.
How to design a frame jig
“Table flush jigs" or “frame hockey pucks” are cylindrical stock that we turn down and then have a hole in the middle to go into the optical table.
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Making your frame is fundamentally an exercise in precision locating and weldment construction, your main considerations should be datums (a fixed starting point) and stiffness. The optical table is your only reference for both geometric and positional tolerances, ergo, every critical jig you make should reference something about the optical table or something about a tube that is located off of the optical table. There are three main frame categories, critical external, critical internal, and non-critical.
After we fully weld the frame, we do the hardpoints (suspension tabs, ergo tabs, etc.) to mitigate warping from the welding. When welding/jigging, you need to have a planned order -> table flush (bottom layer) to the 2nd and potentially 3rd level, roll hoops, everything else (cross-braces) building upMaking your frame is fundamentally an exercise in precision locating and weldment construction, your main considerations should be datums (a fixed starting point) and stiffness. The optical table is your only reference for both geometric and positional tolerances, ergo, every critical jig you make should reference something about the optical table or something about a tube that is located off of the optical table. There are three main frame categories, critical external, critical internal, and non-critical..
How to design a frame jig
“Table flush jigs" or “frame hockey pucks” are cylindrical stock that we turn down and then have a hole in the middle to go into the optical table.
- These support the entire bottom level of the frame, which is the most critical part in welding the frame (i.e. if you start badly from the base, the entire frame will be bad, so support the bottom well and you will have better results overall)
After we fully weld the frame, we do the hardpoints (suspension tabs, ergo tabs, etc.) to mitigate warping from the welding. When welding/jigging, you need to have a planned order -> table flush (bottom layer) to the 2nd and potentially 3rd level, roll hoops, everything else (cross-braces) building up
- Critical external features are parts of your frame that drive car parameters decoupled from the rest of the frame (hardpoints, roll hoops, headrest supports, etc.
- Critical internal features are parts of your frame that only rely on internal geometry (steering column, rear box, etc.) These features of course will matter externally, but it’s more important to locate them to critical mating components, which if done correctly will satisfy external constraints.
- Non-critical features are tubes that don’t matter and are only there to provide structure to your frame, these are your buffers that take up tolerance stacks as they propagate through your frame and are there to support your critical features when the jigs are gone. These are the only tubes in your frame where you should be filling gaps, in an ideal world.
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