Design Guidelines: Sheet Metal Fabrication

Our basic guidelines for sheet metal fabrication include important design considerations to help improve part manufacturability, enhance cosmetic appearance, and reduce overall production time.

Size

Maximum Dimensions

	US	Metric
Size	39 in. x 47 in.	990.6mm x 1,193.8mm
Bend Length	47 in.	1,193.8mm

Minimum Dimensions

	US	Metric
Flat Part	0.250 in. x 0.250 in.	6.35mm x 6.35mm
Formed Part	0.500 in. x 0.500 in.	12.7mm x 12.7mm

Tolerances

Single Surface

	US	Metric
Bends	+/- 1 degree	+/- 1 degree
Offsets	+/- 0.012 in.	+/- 0.304mm
Hole Diameters	+/- 0.005 in.	+/- 0.127mm
Edge to edge/hole; hole to hole	+/- 0.005 in.	+/- 0.127mm
Hardware to edge/hole	+/- 0.010 in.	+/- 0.254mm
Hardware to hardware	+/- 0.015 in.	+/- 0.381mm
Bend to edge	+/- 0.010 in.	+/- 0.254mm
Bend to hole/hardware/bend	+/- 0.015 in.	+/- 0.381mm

Multiple Surface

	US	Metric
Features separated by two or more bends	+/- 0.030 in.	+/- 0.762mm

Tolerances vary on depending on part feature such as bends, offsets, holes, and inserted hardware.

Sheet Metal Surface Finish Guide

Check out our sheet metal guide for a quick snapshot of our Standard and Cosmetic finishing options available for various sheet metal materials.

Download Guide

Materials

Aluminum (1)
Brass (2)
Copper (3)
Stainless Steel (4)
Steel: CR Non-treated (5)
Steel: CR Galvanneal and CR Galvanized (6)

View Materials

Sheet Metal Material Thickness Range

Because sheet metal parts are manufactured from a single sheet of metal, the part must maintain uniform wall thickness. Sheet metal thickness ranges from 0.024 in. (0.609mm) to 0.250 in. (6.35mm).

Steel			Stainless			Aluminum		Copper		Brass
CRS/HRPO*	Galvanneal	Galvanized	304-2B	304-#4	316-2B	5052-H32	6061-T6	C101	C110	C260
0.024	0.028	0.028	0.024	0.024	0.024	0.025	0.025		0.025	0.025
0.030	0.034	0.034	0.029	0.029	0.029	0.032	0.032	0.032	0.032	0.032
0.036	0.040	0.040	0.036	0.036	0.036
0.042						0.040	0.040	0.040	0.040	0.040
0.048	0.052	0.052	0.048	0.048	0.048	0.050	0.050	0.050	0.050	0.050
0.060	0.063	0.063	0.060	0.060	0.060	0.063	0.063	0.064	0.062	0.063
0.075	0.079	0.079	0.075	0.075	0.075	0.080	0.080	0.080	0.080	0.080
0.090	0.093	0.093	0.090	0.090	0.090	0.090	0.090	0.093	0.093	0.093
0.105	0.108	0.108	0.105	0.105	0.105	0.100	0.100
0.120	0.123	0.123	0.120	0.120	0.120	0.125	0.125	0.125	0.125	0.125
0.135*	0.138	0.138	0.135	0.134	0.135
0.164*			0.165			0.160	0.160
0.179*			0.187			0.190	0.190
0.239*			0.250			0.250	0.250

*These thicknesses are available as Hot Rolled, Pickled & Oiled (HRPO) only

Because sheet metal parts are manufactured from a single sheet of metal, the part must maintain uniform wall thickness.

Sheet metal thickness ranges from .0.024 in. (0.609mm) to 0.250 in. (6.35mm).

Z Frame

Want to create designs that convert flat sheets of metal into fully formed three-dimensional parts? Incorporating everything from countersinks and punch-outs to powder coating and silk screening, our functional design aid will show you the way. The Z Frame explores fabrication processes unique to sheet metal and design elements that will improve the structural integrity and appearance of your parts. It even doubles as a desktop organizer.

Get Z Frame

Finishing

We offer welded assemblies, standard mill, edge breaking, and orbital-sanded surface finishes along with a number of additional sheet metal finishing options:

Seam, tack, and stitch welding
Hardware insertion and riveting: Standard PEM sheet metal hardware
Powder coating: A variety of powder coat paint colors available in textured and non-textured finish, including RAL colors.
Silk screening (one- and two-color): Colors mixed to closely match most Pantone numbers
Assemblies: POP-riveted and welded
Plating: Anodize, chromate, zinc, and passivate

In-house powder coating is available to streamline production, and parts are powder coated in compliance with government regulations.

Bend Radius

We hold a +/- 1 degree tolerance on all bend angles. We offer a wide range of common bend radii, but our standard options are .030 (.762mm), .060 (1.524mm), .090 (2.286mm), .120 (3.048mm). These four bend radii tooling choices are available in a 3 day lead time. Minimum flange length on sheet metal parts must be at least 4 times the material thickness.

It is recommended to use the same radii across all bends, and flange length must be at least 4 times the material thickness.

Hems

We form both open and closed hems. The tolerance of a hem is dependent upon the hem’s radius, material thickness, and features near the hem.

We recommend that the minimum inside diameter equals the material thickness, and a hem return length of 6x material thickness.

Offsets

Offsets are used to create Z-shaped profiles in sheet metal parts. We offset height tolerance at +/-0.012 in. (0.304mm) from top of sheet to top of form and recommend an offset of 0.030 in. (0.762mm).

Additional standard options include: available 0.060 in. (1.524mm), 0.093 in. (2.362mm), 0.125 in. (3.175mm), 0.187 in. (4.749mm), 0.213 in. (5.410mm), 0.250 in. (6.35mm), 0.281 in. (7.137mm), and 0.312 in. (7.924mm).

Holes and Slots

Holes and slots should be a minimum of material thickness in diameter. If a material is 0.036 in. (0.914mm) or thinner, the hole should be 0.062 in. (1.574mm) from the material edge; if the material is thicker than 0.036 in. (0.914mm), the hole should be at least 0.125 in. (3.175mm) from the material edge to avoid distortion. If hardware inserts are required, the spacing should be according to manufacturer’s specifications.

Notches and Tabs

Notches must be at least the material’s thickness or 0.04 in. (1.016mm), whichever is greater, and can be no longer than 5 times its width. Tabs must be at least 2 times the material’s thickness or 0.126 in. (3.200mm), whichever is greater, and can be no longer than 5 times its width.

Countersinks

We offer both machined and formed countersinks—conical holes cut into a manufactured object allowing a screw, nail, or bolt to be inserted flush with the surface.

We recommend the major diameters of countersinks measure between 0.090 in. (2.286mm) and 0.500 in. (12.7mm) using one of the following standard angles: 82°, 90°, 100°, and 120°.

Tolerance for formed countersink major diameter is +/- 0.010 in. (0.254mm).