In the last installment, I built a wooden buck to help make a ’27 Ford roadster body. This time, I’ll make the rear section of the body, the turtle deck.
The first panel I’ll make is the one below the decklid. This portion of the buck is remova
As a recap, the primary purpose of a buck is to provide a target to aim for while shaping the sheetmetal panels. Some areas of this buck have been reinforced so the metal can be hammered directly against it. As you’ll see, this will be very helpful for some of the details, like the flanges on the edges of the panels, and the radiused top edge of the turtle deck sides.
I started with the easiest panel; the one below the decklid. This panel has a 1-1/4-inch flange on all sides, so I started by cutting a piece of metal about 3 inches oversize to allow for the flanges, plus a little extra material. The alloy I’m using is 3003 H-14 aluminum, 0.062 thickness (1/16 inch). This is a popular choice for jobs like this, since it’s a nice, easy-to-form material that’s ideal for welding.
A piece of 0.063-inch 3003 H-14 aluminum is cut slightly oversize, and an English wheel is
The first tool I used was an English wheel, which is a great tool for shaping low-crown panels. This job could be done with a pneumatic planishing hammer, but an English wheel makes it fast and easy, and once you’ve mastered the proper tracking patterns with the machine, it’s not too difficult to get a nice, uniform crown on the entire panel.
Once the panel was properly shaped, the edge work was next. I formed the flanges on this piece by hammering the metal right against the hammerform. To do a proper job of this, clamping blocks were made. These keep the metal next to the flange from changing shape, and they prevent the clamps from leaving marks on the metal. I annealed the edges with an oxy-acetylene torch to ease the forming of the flanges.
Once the panel has the proper contours, the flanges are formed by hammering them against t
Next, I tackled the panel above the decklid, the “tulip” panel. This one is a bit smaller than the first, but more difficult to form since it has a reverse curve; it’s convex side-to-side, but concave front-to-back. Again, I did the shaping with an English wheel, but the procedure for making a reverse curve is different—most of the work is done by stretching the edges. I wheeled this panel very carefully, working out any problem areas as I went. It’s difficult to correct the shape of a reverse curve if it gets too far out of whack.
After the panel was shaped, it was trimmed to size, and I put a 5/16-inch bead on the front edge. The stock T doesn’t have this detail, but I want to have a bead running all around the cockpit opening on my car. I used my electric drive Lazze beading machine for this, but a manual machine would work, too. Next, the flanges on the other three edges of the panel were formed by hammering against the buck, just like the lower panel.
The turtle deck sides were next, and these are complex parts to make. They are dead flat on the sides, but they have a graduated-radius curve on the top edge. In addition, each panel has a straight bead on the inner edge, a curved bead around the wheelwell opening, plus flanged edges, and a recess for the wheelwell.
The straight top edge is the only one that could be bent on a sheetmetal brake. The reflections on the panel show how smoothly it was shaped.
The “tulip” panel above the decklid is next. This panel has a reverse curve, so a special tracking technique is used with the English wheel, stretching the edges.
The panel is checked against the buck repeatedly, and the shape is adjusted until it fits accurately.
A beading machine is used on the front edge of the panel. The original panel did not have this bead, but I’m extending this feature all around the cockpit opening.
Now the panel is marked against the buck, so the edges can be trimmed for flanging. This panel will have a 1-1/4-inch flange on three sides.
The flanges are formed by hammering against the buck. It’s essential to use a clamping block to keep the edge smooth, and to eliminate marking from the clamps.
Here’s the end flange after hammering. It’s 90 percent smooth at this point, and a little hammer and dolly work and sanding will finish it off.
Here’s the panel with all of the edgework completed.
The side panel will be made from three pieces; the top, side, and wheelwell. Here I’m using tape to plot the break between the top and side panel.
Paper is used to make a pattern for the aluminum side panel. I can feel the tape line through the paper, and I’m using a pen to mark the paper for trimming.
A layout is done for the wheelwell. I’m temporarily attaching a center pivot here to ensure the bead around the wheelwell opening is made precisely.
This is a Dake Universal machine, fitted with beading dies. This is a great way to form a bead in a large, awkward panel like this. Note the support table under the work.
Here’s the finished bead on the turtle deck side panel. Using a center pivot eliminated any guesswork for this crucial detail.
The beading dies in the Dake machine were modified to work on a flanged panel. Here I’m forming the bead on the top panel.
Here you can see the bead formed right at the edge of the flange. Next, I’ll use a shrinker and stretcher to contour the panel to match the profile of the buck.
After the edge is properly contoured, it is temporarily fastened to the buck with screws. I’m using a caulking tool here to work the metal down tightly against the buck.