Roadster Rhinoplasty, Part I


Building a track nose for a Ford roadster

By Ryan Manson *

With the majority of the primary metalwork completed on the Project Potvin ’29 Roadster, it’s time to move forward of the main body and on to the front sheet metal. The body is bolted firmly in place and the doors are hung and gapped nicely, so the time has come to fabricate the track nose, grille, and then the hood. The plan calls for fabricating the nose and hood as two separate units from aluminum and mounting them to an inner support structure off the frame. Dzus buttons will secure the tin and facilitate easy removal in case of engine fire, violent blower explosions, or just to check the fluids. Hopefully the first two will never happen and the last will probably happen once or twice, but perhaps just as rarely.

The first item on the list is the track nose. Since the shape of the hood is not only dictated by the shape of the cowl, but also the shape of the nose, this needs to be fabricated and installed before the hood can be sorted out. But before any aluminum can be manipulated into shape, a foundation needs to be laid out in which to form the contoured nose. For this application, the foundation will be in the shape of a wooden buck, formed from ¾-inch sanded plywood. This buck will act as a pattern which each aluminum piece can be compared to while fabricating the actual track nose.         

While a buck can be built any number of ways, this seemed the most logical means to an end, giving us the ability to fine tune the buck as the metal was shaped. It’s also lightweight and easy to work with and will be plenty sturdy to support the nose piece while it’s being fabricated. One thing to keep in mind is that the metal is not formed around the buck. Each piece will be shaped using various tools, machines, and techniques and checked regularly against the buck for fitment. A tiny bit of forming may be necessary with the piece in place on the buck, but it is by no means designed as a dolly of any sort.

The first step in fabricating a buck is to outline the desired shape of what it is that is going to be built. For this case, the hood line, profile, and contour of the nose itself needed to be determined. To get the correct shape, 3/8-inch tubing was used to mimic the shape of the cowl, but scaled to match the taper from the cowl to the front end of the car. Next, the hood centerline is determined by the slope of the cowl top. This provides the width and height of the backside of the track nose. For the profile of the nose itself, a piece of plywood was placed against the front cross member and a rough profile was sketched out until aesthetically pleasing when viewed from the side. Another piece of tubing was bent to match the profile of the nose and the three sections, the backside shape, side profile, and hood centerline were all attached to form a back bone for the shape of the front end. Once pleased with the shape of the mockup tubing skeleton, the profiles can be traced onto the ¾-inch plywood that will form the foundation of the wood buck.

While the fabrication of a wooden buck is not necessary every time a panel is fabricated, for jobs where there are compound curves and necessary parameters to be met, it makes the fabrication process that much easier and more precise. By building a buck that carefully matches the shape and dimensions necessary of the end product ensures that all that time spent fabricating will pay off. With that said, it’s time to make some dust, saw dust that is, and knock out a wooden buck for the old ’29. Stay tuned for next time as we head over to the Roadster Shop where Sam Waltermire will be hammering out the aluminum track nose from our buck. CC

The Roadster Shop
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With the car setup at ride height, a wire skeleton was fabricated from some 3/8-inch tubing to act as a visual aid in creating the front end shape. From this angle, the shape of the nose and the hood top is apparent.
The first step in creating the buck is to trace the shape created from the visual aid. This will give the side profile of the track nose.
The back of the buck is traced from the portion of the tubing frame that was bent to match the contour of the cowl. This will ensure that the hood will have the same contour along its entire length.
To keep the vertical, side piece nice and perpendicular to the back side, a couple of pieces of angle iron are clamped in place. Notice the centerline that was marked on the back piece. Because the track nose needs to be as identical as possible from one side to the other, it’s important that the profile piece (the vertical board) be perfectly centered to the back side of the buck.
Here’s a couple of tools that came in handy when assembling the buck. A pneumatic nail gun made quick assembly of the stringers, while a 90-degree pneumatic grinder with a 60-grit sanding disc made fine tuning the shape of each piece a breeze. Once all the stringer sections are in place, Liquid Nails was applied to every joint ensuring the structure was as strong as possible.
When it comes to fabricating the stringers for the wooden buck, there is no formula. For this buck, a basic curve was laid out on each piece and cut accordingly. As each stringer was assembled to the rest of the buck, the necessary shape that each piece needed to be modified to became apparent. Here you can see the basic shape of the top stringer. It will be modified later to better flow with the rest of the buck.
Here’s the four side stringers mocked up in place on the buck. Notice how each one is slightly longer than the side profile piece leaving ample material to trim to fit.
Once all eight stringers are cut out, it’s time to shape them to the buck. Since both sides of the buck need to be as identical as possible, each adjacent stringer is nailed together and formed as one unit.
Since the buck and the stringers don’t serve a load bearing function, each stringer was drilled out with a hole saw to make the buck lighter and easier to work with.
From this angle, it’s easier to see how the shape of each pair of stringers was kept identical. This will pay off when the time comes to fabricate the actual aluminum nose since our buck will be identical from one side to another. Once formed, the two pieces are separated, resulting in two identical pieces, one for each side of the buck.
The first two stringers have been roughed into shape and are in place. Notice that the top of each stringer is blended to match the profile of the side piece.
While the stringers are attached to the back and side pieces of the buck, it’s important that they don’t pull the side piece towards one side. A level is clamped in place while each stringer is attached to ensure that the perpendicularity of the two pieces remains consistent.
With the buck complete, it’s mocked up to the car and tape lines are drawn to mimic the hood lines. Once the buck is in place in respect to the rest of the car, it’s easier to get an overall idea of what the shape of the nose will be. We noticed that the shape of the buck wasn’t as streamlined as we’d like it to be, so each stringer was reworked until the desired shape was achieved.
Here’s an example of a wooden buck built by Marcel’s Custom Metal for a streamliner they built. Notice how the overall design of their buck is similar to our track nose design only on a much larger scale. This is a great example of why building a buck is so important.