Get a chunk of 3/4" Balsamic Birch plywood bigger than the section you
need. Use a 3/4" cove bit in the router to cut the pattern you want. Cut
a second sheet of plywood to fit over the top, cut the same pattern all
the way through. Clamp the whole works together and place on a SOLID
surface (concrete block or el cheapo Harbor Freight anvil) Make a
tamping tool from green ash (shovel or hammer handle) about 1-1/2" wide
x5/8" with the 3/8" radius. Start tapping.


Ray Field wrote:

Metal worms have eaten a few holes in my '68 Austin front floors. Original
pans have half round stiffening ribs pressed into them.
Is there any simple method of reproducing these ribs in sheet metal 0.034 to
0.040 inch thick using hand tools, arbor press, heavy vice or other simple
workshop tools.
Ribs are semi circular cross section 3/8 inch radius, longest rib about 9
inches, other ribs same size are at right angle but separated by 3/4 inch
from cross rib. Will be making up patches about 9 inches square.
Any ideas or methodology will be appreciated (not car crusher or Jewish
lightning please).
Ray