01] Here is a piece of uncovered sheetmetal in an interior. It needs to be structural while also looking good. Holes with flared, concave edges from a dimple die are a popular solution these days.
02] Dimple-die kits are available from different metal-fabrication tool shops. Ours, from Mittler Bros Machine and Tool, retails for around $45 (a set of nine sizes is $350), and only requires a wrench to operate. Others require a press or vise. The flare tools are available in sizes from ½ inch to 2½ inches.
03] We began by drawing a pattern on our cut bit of sheetmetal, intending to add two 1¼-inch holes.
04] We simply laid our tool against the mark to make sure the two holes weren’t too close to each other, otherwise they would crinkle the metal.
05] After cutting the hole, we placed the small end of the tool on the side of the metal we wanted smooth.
06] We completely tightened the bolt until the tool was flush on both sides.
07] Here is the piece after tightening and removing the tool.
08] Here is the finished piece perfect for internal structural panel or exposed cosmetic piece of sheetmetal. The Mittler tool is good for up to 16-gauge sheet metal and 14-gauge aluminum.
Jay Stone, who helped us with this project, first learned from Ron and Sue Fornier’s book called Metal Fabricator’s Handbook. There are a tremendous amount of metal-fabrication books available from CarTech (CarTechBooks.com) and Motorbooks (Motorbooks.com).
