You can e-mail your questions to Professor Hammer at firstname.lastname@example.org, or mail to Professor Hammer, c/o CLASSIC TRUCKS Magazine, 774 S. Placentia Ave., Placentia, CA 92870. We'll print your name and city unless you request otherwise. Ron Covell has made many DVDs on metalworking processes, and offers an ongoing series of workshops across the nation covering all aspects of metalworking. Check them out online at www.covell.biz, or call for a current schedule of workshops and their free catalog of DVDs and fine-quality metalworking tools. Phone 800-747-4631, or 831-768-0705. You can send a request by mail to Covell Creative Metalworking, 106 Airport Blvd #105, Freedom, CA 95019.
Q I plan on doing some trimming on the fenders of my project vehicle, but I don't want to just slip a strip of plastic over the cut edges. I've heard of slitting steel fuel line with a Dremel tool, and welding that over the cut edges. This seems quite labor intensive, and I'd guess it would be hard to keep the slit centered on the tube as I'm cutting. If I was making a complete fender from scratch, or if I was going to make fender flares and weld them on, I could take care of it. But in this case I plan on trimming the original fenders and not adding anything to them. Is there some relatively quick and easy way to convert cut edges to smooth edges? I won't be making a showpiece, so it'll be a case of "close enough is good enough."
A There are many, many options for finishing a raw metal edge. Putting slit tubing over the edge is a nice way to go, but as you have surmised, making the slit in the tubing is no small feat, and I wouldn't approach the job that way because of the labor-intensive nature of the cutting.
Another approach is to weld a solid round bar to the metal edge. This could be as small or as large as you want, but 5/16- or 3/8-inch bar might be a good compromise between strength, weight, and workability. If you do take this approach, there are several variations you might consider. One is to weld the sheetmetal flush with the top of the bar (as pictured), another is to weld it flush with the bottom (so the bar sticks up like a bead), or you could split the difference and weld the sheetmetal to the center of the bar.
Welding the metal to either the top or bottom of the bar is straightforward. You can easily clamp the sheemetal tightly against the bar, which will keep it from distorting much. If you try welding the sheetmetal to the center of the bar, you'll have to trim the sheetmetal much more accurately, or you'll have gaps that will be hard to fill by welding. A further difficulty of this approach is that you'll have problems with the metal warping as you weld. The sheetmetal can easily move up and down against the edge of the round bar, since it has no restraint, and the shrinking forces of the weld are sure to cause the sheetmetal to move a lot, making it very difficult to keep it centered on the bar.
Another approach is to wire the edge. This is how the edges of most car fenders were finished until the mid 1930s. This approach is a bit time-consuming, but it creates a strong, beautiful edge if done correctly. The best way to wire an edge is to first bend a 90-degree flange 2 1/2 times the wire diameter. (Fords used 1/8-inch wire, so for wire that size, a 5/16-inch flange is perfect.) Next, the wire is contoured to be a tight fit inside the flange, then it's clamped into place (I use Vise-Grips for this), and the sheetmetal is hammered tightly against the wire.
The simplest way to finish an edge is to form a hem. Simply fold the metal over, so it's double the thickness at the edge. Again, you would start by making a 90-degree flange, then you'd keep hammering the flange over until it lays flat against the panel. Nearly all doorskins and decklids have hemmed edges. While a hemmed edge is not quite as strong as a wired edge, it's considerably stronger than a raw edge, and much safer, too, since the folded edge is quite smooth. You can do this job entirely with a hammer and dolly, or you can make a simple flanging tool, which can speed up the process.
Q I'm nearing completion of my '40 Ford pickup and would like to lower the stock, transverse leaf spring rearend. I have installed a monoleaf rear spring with minimal arc, which lowered it about 5 inches. I would like to lower it 3 or 4 more inches. The only way I see is to use longer spring shackles. What potential problems might I encounter and how can I fix them? I'm trying not to make any permanent mods.
El Paso, TX
A Using longer shackles is a very feasible way to lower your truck even more. With longer-than-stock shackles, when you corner hard, the rearend can move sideways in the frame, conceivably causing tire-to-fender (or frame) interference. This can be prevented by using a Panhard bar-you can make your own, or buy one ready-made from a number of suppliers. This could be done as a bolt-on item, if you don't want to do any welding on the frame or rearend. Remember that the longer a Panhard bar is, the better it works!