Double Seam Joint In Sheet Metal

Hemming and seaming are two similar metalworking processes in which a sheet metal edge is rolled over onto itself.

Double seam joint in sheet metal. Hems are commonly used to reinforce an edge hide burrs and rough edges and improve appearance. Grooved seam are a type of self locking joint used commonly in the fabrication of cylindrical and conical objects. Hemming is the process in which the edge is rolled flush to itself while a seam joins the edges of two materials. The extra material allowance for a grooved seam is 3 times the width w of the seam one half of this amount being added to each edge note.

Multiply 1 8 by 2 1 2 and your answer will be 5 16 inch which you will allow when laying out sheet metal for making the wire edge. Up to 4 times the material thickness may also need to be added for thicker. The double seam is also called acme lock hammer lock and pipe lock in the sheet metal trade. Some seams are created entirely by machine or in a metal shop while others are made to snap together without requiring welding or soldering on site.

It is normally used in the fabrication and joining of the round pipe or in joining or piecing together two sheets of metal to form a large wrap around section for square or rectangular ductwork. The seam can be on the outside or on the inside. A variety of seams are used to connect pieces of sheet metal in construction auto body creation and fine art sculpture.