Having built one half of a wooden car body buck, I’m making a wire frame buck. The plan is to bend 5mm steel bar around my wooden buck. Every bar I bend around the buck touches with less than 1mm gap. I’ve made sure that no force is required to ‘spring’ the bars into place.
There are incredibly talented metalwork gurus that could probably build a car without a buck. There are also those that could envision a car from an open frame buck. Unfortunately, I’m not one of those people.
Solid or Wire Frame Buck?
A good buck allows access to both sides of a panel with body-working tools. During the fabrication of parts panel fitment can be checked around a skeletal frame.
A solid buck although perfect for seeing the flow of body lines and curves doesn’t fill that need. A solid station buck gives you the ability to stand back from the project and view every shape and angle in three dimensions. However, with solid station bucks, access to the rear of a panel is impossible.
To get the basic shape of many panels, a wire frame buck is perfect. The 3D grid allows panels to be perfected at a network of points.
Keeping the bar spacing large enough for a hammer and dolly is ideal, however on tight non-uniform radii, a couple of mine only allow visual inspection.
Transferring from Solid to Wire Frame
My buck is pretty thick and would be great for hammering some panels around. However there are areas that are less then 15mm thick and would crumble if hit repeatedly. To perfect some panels, I’ll make small solid hammer-forms that are strong enough to beat panels around.
The two wheel arches and running boards are unfinished but already have over 30metres of bar in them. By the time I’m finished, just this half, I’ll have used over 100metres.
Each of the bars that run from front to back are made in identical pairs. They run parallel so hopefully I can mirror one side to the other simply by reversing the order. There are also bars that run from side to side and by rotating these 180º I can use them on the opposite side.
The bars were bent using my motorized sheet metal roller, so hopefully the bars are kink free.
Lifting the Wire frame over the chassis
I’ve lifted it off and unsurprisingly it has very little structural strength. Once lifted over the chassis there will be dozens of bars tracked to the chassis holding it in shape. The final body will be simply bolted to the chassis.
I been hoarding X/Y laser line pointers, height gauges, squares and spirit levels. Hopefully, I’ll be able to weld up the opposite side somewhere close to where I need it. There will be several bars that will be much trickier to replicate from one side to the other and I’ll need to work them out one by one as I get to them.
Once I’m happy with the shape, I’ll start making bodywork mounts such as those for the running boards and inner wings. These will be used as datum points. I want to build the whole internal, structure before external panels are started. This hidden internal structure will provide strength and be a mould for external panels.
Although the buck was generated from a wireframe CAD model, so many design tweaks were made at the buck stage, I have no idea quite how the frame will sit over the chassis.
Lifting the wireframe was easy, but getting it into the right position is going to be painstaking. Checking things like steering clearance was possible by propping it on cardboard boxes. On full lock at full rebound I made it just touch. In real life, in that situation trouble would already have happened. Taxi’s have similar turning circles, so a steering lock wouldn’t be an issue.
Other very minor issues included the air filter position and the petrol tank. Nothing that a few minutes over a coffee wouldn’t sort.
1930’s Hot Rod Styling
I’m building a 1930’s style Hot Rod body over a Caterham style chassis. I need to disguise the long bonnet and two seats, otherwise there’s a serious chance this could end up looking like another gentry style kit car or fake Morgan. Therefore the styling and wire frame buck may need the odd tweak.
Inside wheel arches and under the bonnet, there will be several materials used, such as aluminium and copper. There will also be exposed hand hammered rivets, plenty of bead rollering, louvering and dimple die holes.