Talk to Your Manufacturer About Sheet Metal Sizes Before Designing Your Part (Updated for 2025)

Last updated on January 27th, 2025 at 10:00 am

Choose the Right Gauge at Approved Sheet Metal

When you’re working with sheet metal, choosing the right gauge or thickness for your material may seem simple enough. But rushing the design process is counterproductive if you don’t know the materials and sizes your manufacturer carries. Wouldn’t you like to get everything right the first time?

Material Thicknesses: What’s Really Out There?

Unfortunately, not all sheet metal fabrication shops carry standard sizes for every sheet metal material. The last thing you want is to design for a specific material thickness, only to find that it’s not available at your local manufacturer. You may think you can avoid this hassle by designing a part and selecting the material later, but that often leads to costly tolerance adjustment and rework.

So, what’s the best way to avoid these aggravations? Ask your manufacturer what sheet metal gauges they have in stock, then design your part accordingly.

Design Implications of Material Thickness

The thickness of the sheet metal you select has significant implications on the design, functionality, and manufacturability of your part. Making the right choice ensures your design meets performance requirements without incurring unnecessary costs or production delays. Below are some key factors to consider:

1. Bend Radii and Formability

• Thicker Materials: Require larger bend radii to avoid cracking or warping during the forming process. This is particularly important for materials like aluminum 6061, which are more prone to cracking when bent sharply.
• Thinner Materials: Allow for tighter bends but may lose rigidity, increasing the risk of deformation or “oil-canning” (a slight bulge or wobble in flat sections).

2. Structural Integrity

• Thin Gauges: While cost-effective and lightweight, thin materials may require additional stiffening features, such as ribs or flanges, to maintain rigidity and prevent buckling under load.
• Thick Gauges: Offer superior strength and durability but may add unnecessary weight and cost if over-specified for the application.

3. Fastening and Joining

• The choice of material thickness affects the selection of fasteners, welding techniques, and adhesive types:
  • Thin Materials: May not provide enough thread depth for screws or bolts, requiring the use of rivets or nut plates.
  • Thick Materials: Are more forgiving in threaded applications but may require specialized equipment for joining.

4. Tolerance Stack-Up

• Material thickness tolerances (e.g., +/- 0.005″) can influence the accuracy of mating parts in assemblies. Thicker materials with looser tolerances may require additional adjustments during production or assembly to ensure proper fit.

5. Hole Sizes and Cut Features

• Thin Materials: Allow for smaller, more intricate cutouts with clean edges. However, they may warp or distort during cutting, especially if not supported properly.
• Thick Materials: Support larger holes and cutouts but may require higher power laser cutting or more robust punching tools, increasing production costs.

6. Aesthetic Considerations

• The visible edge of the material (e.g., on exposed parts or decorative panels) changes with thickness. Thicker edges may give a sturdier appearance, while thinner edges are often perceived as more lightweight or modern.

7. Weight and Performance Trade-offs

• Choosing the right thickness is essential for balancing weight and performance. For example:
  • Thinner Materials: Are ideal for lightweight applications, such as aerospace or electronics enclosures.
  • Thicker Materials: Provide the durability needed for heavy-duty applications, like structural supports or industrial equipment.

8. Secondary Processes

• Material thickness influences the feasibility of secondary processes such as embossing, countersinking, or dimpling. For example, thicker materials may not form embossments as easily as thinner sheets.

Choosing the Right Sheet Metal Gauge at Approved Sheet Metal

Rapid delivery is one of our top priorities, so we keep common materials and gauges on hand and ready for use at our metal fabrication shop. As part of our process, we help our clients choose the right material thickness for their parts, using our expertise to determine the ideal solution.

Case Study: No Standard Size, No Problem!

One of our customers recently asked us to assemble over 100 sheet metal components. They had designed the structural part of the assembly with a standard .187″ thick steel. The only problem was that in our local area (Hudson, New Hampshire), only one of our suppliers offered this gauge. Ordering from that supplier would have extended our lead time to 3-4 days instead of just 1 and increased cost by 30% per pound.
So, how did we solve their problem?

We recommended a .197″ or 7 GA instead. Although the difference was only .008″, we had to make sure that the inside-outside mating surfaces and the tolerance stackup wouldn’t cause discrepancies in form, fit, or function. To avoid errors and give the team on our shop floor accurate geometry, we used SolidWorks to edit the CAD models to the exact thickness we measured the material.

Our customer was thrilled that we found a way to deliver on our short lead time and save them 30% per pound.

Are you unsure about the ideal material thickness for your part? Don’t hesitate to give us a call! We’ll help you make the right choice before you start designing.

Recommended Default Sheet Metal Tolerances

DIM	Tolerance (MM)	Tolerance (Inches)	Description
A	± 0.13	± 0.005	Sheared Edge to Hole
B	± 0.13	± 0.005	2 Holes on One Surface
C	± 0.25	± 0.010	Formed Edge to Hole
D*	± 0.76	± 0.030	Holes Across 2 Bends
E*	± 0.76	± 0.030	Holes Across 4 Bends
F	± 0.25	± 0.010	Sheared Edge to Bend
G	± 0.38	± 0.015	Across 2 Bends
H*	± 0.76	± 0.030	Formed Part

Noted dimensions are to be taken while the part is in a restrained condition. Noted dimensions are for parts within a 12″ envelope.
* Dimensions D, E and H are not recommended forms of dimensioning
These tolerances are recommended and best practices. We can obtain tighter tolerances (depending on part geometry/ construction), contact us for more information Download PDF

Precision Sheet Metal Size FAQ

What factors should I consider when choosing the right sheet metal gauge for my project?

To make an informed choice, consult with your manufacturer to determine the sheet metal gauges they have in stock, and then design your part accordingly. This proactive approach can help you avoid material availability issues and costly adjustments down the line.

How can I ensure I’m using the right material thickness for my sheet metal project?

To avoid such issues, it’s best to consult with your manufacturer. They can provide guidance on the ideal material thickness based on their inventory and expertise, ensuring your project runs smoothly.

Can you share a real-life example of how choosing the right sheet metal gauge made a significant difference in a project?

Recently, a customer faced a situation where they had designed a part using a specific thickness that was available from only one supplier. By working with us, we recommended a slight thickness adjustment that not only saved them time but also reduced costs significantly. This case study emphasizes the value of flexibility in material selection.

How can I ensure rapid delivery of sheet metal components for my project?

At Approved Sheet Metal, we prioritize rapid delivery by keeping common materials and gauges in stock. To ensure swift project completion, it’s important to collaborate with a fabrication shop that values quick turnarounds and has a wide selection of materials readily available.

What should I do if I’m unsure about the ideal material thickness for my sheet metal part?

Don’t hesitate to reach out to us for assistance. Our team can help you select the right material thickness before you begin the design process, ensuring that your project proceeds without any hitches.