OK, so you have decided to chop the top on your hot rod. Your next decision will be how much. The height and length of your torso will be factors in this decision. Also, you want the car to be proportional. A good rule is two-thirds body, one-third top.
The current victim scheduled for surgery is a ’31 Ford Model A. For good proportioning, a 4-inch chop on a ’30-31 body will achieve this, but your taste and requirements will vary.
This month we’ll focus on the major cerebral surgery: cutting and setting the top. Next month we are going to sweat the small stuff: trim, wood, garnish moldings, and windshield frame.
Special thanks to my friend Mark Anderson who helped me collaborate on some of these solutions.
[1] Before we cut the top,...
[1] Before we cut the top, we removed the vertical wood on each side of the rear window. You can cut right through it but it makes for a stronger frame if you remove and rework it. More on this later.
[2] OK, measured, marked,...
[2] OK, measured, marked, and ready to go.
[3] Here we go—with an electric...
[3] Here we go—with an electric grinder/cut-off wheel, the first cut is made.
[4] The mandatory “lifting-off-the-top-for-the-first-time”...
[4] The mandatory “lifting-off-the-top-for-the-first-time” picture.
[5] Before we cut the top,...
[5] Before we cut the top, we removed the whole outer skin of the A-pillar. The cut was made in the inside corner by the windshield and the other was about 1/4 inch from the rear edge.
[6] With the top off, it’s...
[6] With the top off, it’s a good time to weld up any areas that would be difficult to do upside down.
[7] Since the A-pillar is...
[7] Since the A-pillar is tapered it can be difficult to join the outer skin without pie cutting. This way we can remove a little material on the removed piece and fit it in without a seam in the middle. But the most important reason is because of the structural metal under the A-pillar skin. Unless you remove it, you will not be able to join these parts for a proper strength. Now you can weld it up solid for strength.
[8] Now we can bring the top...
[8] Now we can bring the top together with the body. With the help of these butt-weld clamps from Eastwood, it will ensure an even distance between the two panels. The metal tends to buckle in, so as you weld this seam it is important to hammer out the metal from the inside as you go. (Tip: If you grind a slight taper to the sliver that goes between the metal panels you will find it easier to remove them afterward.)
[9] After the roof is tacked...
[9] After the roof is tacked into place it is a good idea to do a test-fit with the chopped doors. Now would be the time to fix anything that will not line up. The B-pillar has a tendency to get sucked in when you weld it together. This looks good.
[10] As you are tacking the...
[10] As you are tacking the posts together you want to use a straightedge on the outside. Also, make sure the reveal line lines up perfectly.
[11] We welded the top from...
[11] We welded the top from the inside. As this will be covered with upholstery there is no need for dressing these welds, plus the seam will be stronger for it.
[12] There’s hardly any filler...
[12] There’s hardly any filler that will be needed here.
[13] Here you can see how...
[13] Here you can see how nice the A-pillar came out.
[14] Chopping the doors is...
[14] Chopping the doors is not brain surgery—it’s Model A surgery.
[15] I cut the posts right...
[15] I cut the posts right in the middle, which seems to work best.
[16] Using some sturdy angle...
[16] Using some sturdy angle iron helps keeping the post straight during welding.
[17] Always test-fit before...
[17] Always test-fit before welding the doors up solid.
[18] Here you can see the...
[18] Here you can see the necessary pie cutting.
[19] One side is brought together,...
[19] One side is brought together, and one is expanded.
[20] This channel is used...
[20] This channel is used to hold the wind lacing later so it has to remain just that: a channel. In order to avoid filling it with weld I used a flattened-out copper pipe. The weld does not stick to the copper so it is a perfect material for backing the weld seam.
[21] This channel is used...
[21] This channel is used to hold the wind lacing later so it has to remain just that: a channel. In order to avoid filling it with weld I used a flattened-out copper pipe. The weld does not stick to the copper so it is a perfect material for backing the weld seam.
[22] A final test-fit confirms...
[22] A final test-fit confirms a good fit. I am pleased.
[23] Don’t forget to step...
[23] Don’t forget to step away and have a look at the whole picture.
[24] Also, don’t forget to...
[24] Also, don’t forget to roll it out for a full view of your work. This is what keeps the project going.