On my Model A project I channeled the car down over the chassis which required me to build new floor supports and pans. The way I built it all up I needed to make 6 small pans that would fit down in between each supports. This meant I had to nail the bends on either edge so the final inside measurement allowed the pans to drop down in between the supports tightly. I will have to take the pans in and out throughout the rest of the project so I wanted them to drop in and fit snug, but not so tight I needed to use a hammer to force them in (this could also bow the panel).
This means that there’s little room for error when making the two bends on the panel. If I even bent on the wrong side of the mark or had the top leaf of the brake a tiny bit further back than needed the pan wouldn’t fit correctly. I had good luck on most of the panels hitting my bend lines but I had one in particular where the panel would have to be bent or hammered in place and that wasn’t going to work. Normally the only option is to force it in place or junk the panel and start over. The panel was so close I didn’t want to scrap it so I decided to show how to move your bent edge over a fraction of an inch to allow the panel to fit down in perfectly.
I started by using a dolly that matched the shape and size of the bent edge. I prefer a heel dolly for this type of work, but any dolly with a crisp, flat edge will work. You want to hold the dolly so the top edge is tight on the flange and the bottom edge is just off the flange, leaving a small air gap.
Then aim your body hammer swings directly AT the center peak of the bend. This will flatten the bent line and form a new one around the bottom edge of your dolly. Slowly work down the flange, keeping your dolly gap at the bottom consistent so your new bend line is as straight as possible.
Depending on the material you’re using it could take a couple passes to get new bend line defined completely. It’s better to move the bend line slowly rather than all in one pass. Once the new bend is defined hold your dolly tight in that flange and work back and forth planishing the old bend seam flat until it is just a small line in the metal.
The result is a very fine line in the flange which can be sanded smooth or you can leave it as-is if the flange is going to be hidden like this project.
With the edge moved over just a fraction of an inch the pan fits into the opening with light hand pressure and can be held in place with clecos. This procedure saved the time of laying out and making a new panel!
Above is the finished floors all held in place with clecos. I can now quickly and easily remove a panel as I work on the car. In the end the panels will be rosette and stitch welded in place.
-Matt/EW
If you have two (2) pieces of flat stock – at least 1/4″ thick
Clamp them together over your metal (along bend line) and slowly work the hammer back and forth
Below line to make sheet smaller and and above to make it bigger
You could do a similar process by angling the dolly in the other direction and putting the bottom edge of the dolly just above the bend line, but it is much more difficult to reform the bend cleanly.
Great info, I am just beginning my walk to change my hobby to some more serious and that was some thing i may have work harder at than what you just shared.
Thank you
Thanks that is a valuable sheet metal tip for a slightly tight fit. Is there a similar process for a slightly loose fit?
Excellent job and especially useful technique when shop space is scarce. I have used a large steel block in a vise and my welding table edges to accomplish the same with satisfactory results but your solution is another way to address the problem of inaccurately braking a sheet which has happened to me no matter how many times I double check before moving the handles…thanks for sharing!!
Matt: Maybe u already know this , but it is very good way to polish the head of a bolt ( up to 1/2 “)
or a very small screw (dn to 6-32)
use a cordless drill and put the item to be polished in it and run the drill it the opposite direction of the sanding, polishing wheels. this works great and does not affect the threads like pliers does. call me 704-680-4277 if more info is needed.