We've brought you numerous stories on how to chop a roof over the years, as well as recently covering how to cut the glass to match, but one job that always makes a chop seem more complete is when the finished car has working vent windows too. It's a tedious and time-consuming job, but one that is worth the effort involved, and if you are capable of performing the actual chop, reshaping the vent windows is easy in comparison.
While hanging out at Brad Masterson's shop (Masterson Kustom Automobiles) he mentioned he'd be tackling the vent windows on Transmission John's radical '53 Studebaker pickup that had already been chopped, giving us the perfect photo opportunity. Though the hinge system on the Studebaker is different than most cars, the vent window opening at an angle as the lower hinge point is located on the lower curve of the window, the principle is the same as other cars.
Points to remember are to align the upper and lower hinges when the vent window and frame are rebuilt and to ensure the rear edge of the new glass, when it is installed, is in the same location as the original, to maintain a factory-like seal. The Studebaker doesn't use a vertical window channel for the main door glass, unlike most cars, but ensuring the rear edge of the glass, and therefore the rearmost ends of the vent window channel, are correctly located will mean it will seal against the door glass.
To give you an idea of the...
To give you an idea of the job at hand, here's an unchopped vent window and its frame along with an already cut-down version from the other side of the vehicle.
The first job is to remove...
The first job is to remove the vent window from its frame. This will differ depending on the make and model, but most will have a spring-loaded hinge pivot that extends down into the door frame that will need separating, as well as (usually) a riveted top hinge.
On some makes, such as this...
On some makes, such as this Studebaker truck, the riveted top hinge bracket can remain attached to the vent window by grinding away the rivets that attach it to the frame; on others the actual pivot rivet will require removal.
Chopping vent windows is a...
Chopping vent windows is a two-part job; first the frame needs to be cut down, then the vent window itself. Here Brad mocked the frame in place to determine where it would require cutting (arrowed). This cut must be made above the lower hinge point of the vent window to ensure it will still open.
With a V-shaped slot cut on...
With a V-shaped slot cut on the curve of the frame with a cut-off wheel, the top was bent as shown, which helped determine where the next V-slot should be made to continue forming the frame to match the new shape of the window aperture.
With the second slot cut,...
With the second slot cut, the frame was taking shape. You may need to make additional cuts, whatever is necessary to match the shape of the frame to the door. The arrowed bracket is where the frame is attached to the door with screws, and these attachment holes may need to be redrilled to align with the frame.
With the lower section formed...
With the lower section formed to shape, the frame was cut above the lower attachment bracket. The lower part of the frame was then attached to the door using the original attachment point by the vent window latch. The upper section of the frame was tackled in the same manner as the lower. When complete, the frame should fit snug in the door channel and match the shape of the door.
Once satisfied with the shape,...
Once satisfied with the shape, Brad tack-welded the lower section together using a MIG-welder, checked the fit once again, then gas-welded the frame together. He prefers to gas weld as it's easier to fill the V-shaped gaps with this method.
New attachment holes were...
New attachment holes were required where the brackets no longer aligned with their stock holes. Using the stock screws, the frame was next secured from the outside of the door frame.
With the frame secured and...
With the frame secured and Brad satisfied with the overall shape, he tacked everything together, though final welding was saved until the entire job was complete. It could have been done now, as the shape of the frame wouldn't change, but it had to come back out later in the process anyway, so why make more work?
The second part of the job...
The second part of the job could now begin, that of chopping the actual vent window. This was tackled in the same way as the frame, though as this part will be seen, great care was taken to ensure a smooth curve, an equal gap between the window and the door, and to ensure the pieces of window channel were aligned in every plane. The hinge (arrowed) had to be dropped into place before the lower section could be shaped.
Satisfied with the shape of...
Satisfied with the shape of the lower section, Brad started work on the upper.
The upper hinge has to align...
The upper hinge has to align with the lower for the vent window to open correctly. Here you can see the hinge bracket's new position in the frame.
With the window and frame...
With the window and frame removed from the door, some minor adjustments were required to perfect the shape of the window. You can also see where a couple of the tack welds have been cut through to readjust the shape of the channel. This is why everything was tacked and not finish-welded.
The completed window and frame,...
The completed window and frame, ready for final welding. Don't forget the upper hinge bracket requires welding or riveting to the frame as well as welding all the cut sections. It's a time-consuming process but it makes a big difference to a roof chop, giving it a "finished" look.
Switching to the other side...
Switching to the other side of the vehicle for a moment, here's the finished vent window installed minus glass. The hinge works, and the latch still locates on the bracket. Now to the chrome shop...