So it came time to start the CAD part of the buck making project. To make sure I wasn't giving confusing or ambiguous direction to Dan (the guy doing the CAD work), I decided to write down my thoughts/needs. I've found the process of putting words on paper (so to speak) forces me to think things through and verbalize what's going on in my head. Here's what I came up with:
Modern-day Miura Station Buck
Objectives
1. A tool that can be used to provide reliable and repeatable surface information for the Miura body. By surface information I mean body skin shape, placement and measurements from “known” reference points like ground, axle centerlines, windshield, etc. Contour gauges can be lofted from buck stations for purpose of designing and fabricating inner body structures.
2. A tool for verification of body panel shape and form. Body panels can be placed against buck during shaping to verify their fit via visual observation from backside. Buck stations will need “windows” cut in them for visual access.
3. I have constrained workspace in my garage. For short periods of time, I can free up enough space for a full sized station buck but not for the duration of body making phase. I’d like the buck to have adaptable modules such that a module can be used separate from other modules but when the buck modules are joined they should do so with reliable indexing.
4. For purposes of symmetry and accuracy, I’d like to hammer form selected body openings on the buck. Examples include front and rear grill openings, headlight openings, and hood vent openings. Perhaps wheel openings but not sure on that one yet. In general, metal shaping will be done off buck and buck is for shape verification. In these selected areas, hammer form modules should be attachable to buck for shaping and flanging these openings. All body panels to be hammer formed will be made from Al 3003, .063 thickness.
5. I work mostly alone and will at times need to move or re-position the buck and/or buck modules. As such, I’d like to keep buck weight manageable by not over engineering it with over sized structural components.
6. One time use. I am a hobbyist and my intent is to make a single Miura. If a second use is needed, a second buck can be cut from CNC files.
Specifications
1. Buck station thickness: ½ inch
2. Transverse buck station placement should be every 8 inches in general. Placement can be closer in places of rapid body shape change or near edge of buck modules and hammer form modules.
3. Buck design should include 5 modules: front clip, rear clip, middle section, drivers side rocker, and passenger side rocker.
4. Longitudinal and transverse station design in the module interface areas must include a means of reliably indexing the buck modules to one another. A design that requires some buck module disassembly and reassembly to join and index modules together is OK. I can foresee use cases where front plus middle modules minus rear module will be needed and likewise middle plus rear modules minus front.
Ideas
1. Special longitudinal members/stations whose only purpose is to accurately index the buck modules to one another. Given the length of the car (i.e. > 8 ft.), the full length longitudinal stations need to be cut from multiple sheets and joined/indexed together anyway.
Here's a graphic showing buck modules in different colors: