Fabrication Tolerances for Dimensional Variance in Aluminum Bar Stock and Machined Parts
Standard Tolerances For Aluminum Bar Stock
Usually, choosing material thickness is one of the first steps a designer takes when starting a project. We work with nominal thicknesses, so it's important to know the thickness tolerance on the material you chose, in order to know if the final product will be suitable for your application. It's also important when working with bar stock that you factor in finish tolerances. For example, if you add a finish such as powdercoat, you add more thickness - this should be factored into your design at the beginning.
Stocked Aluminum FLAT Bar Stock
| Specified Thickness | Alloy | Tolerance |
| 1/2" x 3/4" | 12.70mm x 19.05mm | 6061-T6 | ± 0.024" | 0.61mm |
| 1/2" x 1" | 12.70mm x 25.4mm | 6061-T6 | ± 0.012" | 0.30mm |
| 1/2" x 2" | 12.70mm x 50.80mm | 6061-T6 | ± 0.024" | 0.61mm |
| 1/2" x 4" | 12.70mm x 101.60mm | 6061-T6 | ± 0.034" | 0.86mm |
| 3/4" x 3/4" | 19.05mm x 19.05mm | 6061-T6 | ± 0.010" | 0.25mm |
| 3/4" x 2" | 19.05mm x 50.80mm | 6061-T6 | ± 0.024" | 0.61mm |
| 3/4" x 4" | 19.05mm x 101.60mm | 6061-T6 | ± 0.034" | 0.86mm |
| 1-1/2" x 2" | 38.10mm x 50.80mm | 6061-T6 | ± 0.024" | 0.61mm |
| 1-1/2" x 3" | 38.10mm x 76.20mm | 6061-T6 | ± 0.024" | 0.61mm |
| 1" x 2" | 25.40mm x 50.80mm | 6061-T6511 | ± 0.024" | 0.61mm |
| 1" x 4" | 25.40mm x 101.60mm | 6061-T6511 | ± 0.034" | 0.86mm |
| 1" x 6" | 25.40mm x 152.40mm | 6061-T6 | ± 0.044" | 1.18mm |
| 2" x 2" | 50.80mm x 50.80mm | 6061-T6511 | ± 0.024" | 0.61mm |
| 2" x 3" | 50.80mm x 76.20mm | 6061-T6511 | ± 0.024" | 0.61mm |
| 3" x 3" | 76.20mm x 76.20mm | 6061-T6 | ± 0.034" | 0.86mm |
Stocked Aluminum ROUND Bar Stock
| Specified Thickness | Alloy | Tolerance |
| 1" | 25.4mm | 6061-T6 | ± 0.012" | 0.30mm |
| 1.5" | 38.1mm | 6061-T6 | ± 0.014" | 0.36mm |
| 2" | 50.8mm | 6061-T6 | ± 0.024" | 0.61mm |
| 2.5" | 63.5mm | 6061-T6 | ± 0.024" | 0.61mm |
| 3" | 76.2mm | 6061-T6 | ± 0.024" | 0.61mm |
| 4" | 101.6mm | 6061-T6 | ± 0.034" | 0.86mm |
| 6" | 152.4mm | 6061-T6 | ± 0.044" | 1.18mm |