How is Expanded Metal Mesh Measured and Used?

In Expanded Metal Baskets

Marlin Steel on March 5, 2020
Expanded Metal Closeup shot
Expanded metal mesh is an excellent option for custom wire baskets that need more tensile strength than wires can provide, and more open space than what sheet metal offers without wasting metal. However, there may be some confusion about how expanded metal mesh is measured.

What is Expanded Metal Mesh?

Stainless steel expanded metal mesh is made of a single solid sheet of material that has been compressed and stretched. The expanded metal grating is useful for heavyweight custom parts washing applications, as well as providing open space for air flow and drainage.

Types of Expanded Metal Mesh

There are two distinct varieties of expanded stainless steel mesh that can be used for baskets: standard and flattened. The term “standard expanded metal” refers to the metal as it comes out of the expanding machine. On the other hand, flattened expanded metal is what happens when standard expanded metal is put through a cold rolling steel mill to flatten the expanded stainless steel mesh out.

How is Expanded Metal Made?

How stainless steel expanded metal is made depends on the type. In the process of making standard expanded metal, the expander and the sheet metal’s thickness will determine the specific dimensions of the expanded metal, though thickness of the metal strands and the open space between them will be consistent and regular. Depending on the expanding equipment, standard expanded metal may have a slightly rounded appearance. This helps reduce any risk of wash process runoff collecting in the expanded metal basket.

Flattened expanded metal is put through a cold rolling steel to flatten the mesh. This makes the expanded metal grating thinner, flatter, and wider/longer. This type of expanded metal may have dimensions slightly different from any original estimates since it can be difficult to predict how much expansion will occur during the flattening process.

The choice between flattened and standard expanded metal mesh depends on the application. Standard expanded metal is often more useful for parts washing applications because the raised centers of the bonds prevent liquids from pooling in the basket. Flattened expanded metal, on the other hand, may be more useful for certain parts handling applications or for making larger custom mesh baskets slightly lighter by thinning out the metal mesh.

To help you with future expanded metal mesh orders, here’s a quick guide to measuring expanded metal mesh sizes:

Expanded Metal Mesh Terms

Here is a brief list of stainless steel expanded metal terms that you need to know:

  • Strands. This is the term for the solid metal portions of the expanded metal grating. In the diagram at the top of the article, the strands are 0.107" wide.
  • Bonds. This is the term for intersections of strands.
  • Short Way of Design (SWD). The distance between the centers of bond strands in the mesh when measured along the short diamond diagonal. To illustrate this, in a diamond pattern shape like “<>,” the SWD would be measured from top to bottom. In the diagram above, the SWD would be approximately 0.372" (0.265" SWO plus 0.107" of strand thickness).
  • Long Way of Design (LWD). The distance between the centers of bond strands in the mesh when measured along the long diamond diagonal. In a diamond pattern shape “<>,” LWD would be measured from right to left. In the diagram above, the LWD would be approximately 1.107" (1" LWO plus 0.107" of strand thickness).
  • Short Way of Opening (SWO). The distance between the inside edges between bonds when measured across the short diamond diagonal. The difference from SWD is that SWO measures open space, while SWD measures the space from the center of one bond strand to the next. In the diagram above, the SWO would be 0.265".
  • Long Way of Opening (LWO). The distance between the inside edges between bond strands when measured across the long diamond diagonal. Like with SWO, the difference between LWO and LWD is that LWO measures open space only, while LWD measures to the center of a bond strand. In the diagram above, the LWO would be 1".
  • Strand Thickness. A measure of the thickness of a strand of expanded metal.
  • Strand Width. How wide a strand of expanded metal is.

Measuring Expanded Metal Mesh

When measuring expanded stainless steel metal mesh, it’s important to consider the overall size of the metal plate after it is expanded, its long and short way of opening, and its strand thickness and width. This is because each of these factors will affect the basket’s performance.

For example, larger LWOs and SWOs mean that the holes in the mesh are larger, which improves air flow for the expanded stainless steel mesh basket. On the other hand, thicker and wider strands tend to be stronger than thinner strands.

Comparing LWO and SWO against LWD and SWD helps to confirm the width of metal strands and overall open space of the mesh. For example, if the SWD and LWD of the mesh is 0.5” and 1”, and the SWO and LWO is 0.4” and 0.8”, then the width of the bond should be approximately 0.2” x 0.4”. This would provide a strand width of 0.1”. This would also create an open space of roughly 0.5 inches squared for each opening in the mesh.

Choosing The Right Stainless Steel Expanded Metal

The choice to determine which expanded metal grating to use will depend on your application. Since standard expanded metal has a slightly rounded surface, it may be more useful for part-washing applications where there needs to be no residue from runoff.

In comparison, flattened stainless steel expanded metal has a flatter surface that may be better for materials-handling applications to help distribute weight or prevent parts from sticking to the expanded metal grating. When weight is an issue, flattened expanded metal is lighter and slightly thinner.

It is important to note that if you’re working with flattened expanded metal, the LWO, SWO, LWD, and SWD measurements may vary somewhat depending on the direction that the metal was flattened. This introduces an element of variability that makes it harder to precisely control open space in the expanded metal basket. Flattening also makes the metal mesh thinner.

Standard stainless steel expanded metal mesh, on the other hand, has more consistent open space between strands—which is based on the machine that is expanding the sheet metal.

Want to know more about expanded stainless steel mesh baskets? Reach out to the Marlin Steel team to learn more about the benefits of expanded metal mesh.


Author: Marlin Steel
Marlin Steel
Marlin Steel is a leading manufacturer of custom‐engineered products from steel wire and sheet metal. Its industrial material handling containers serve many industries including aerospace, defense, medical and automotive.

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