Our flat washers are 651 Silicon Bronze alloy.
| SIZE | Inner Diameter | Outer Diameter |
| #8 | 0.170" (4.3mm) | 0.375" (9.6mm) |
| #10 | 0.200" (5.1mm) | 0.427" (10.9mm) |
| #12 | 0.225" (5.8mm) | 0.500" (12.7mm) |
| 1/4" | 0.250" (6.4mm) | 0.685" (17.4mm) |
| 5/16" | 0.312" (7.9mm) | 0.750" (19.0mm) |
| 3/8" | 0.375" (9.6mm) | 0.875" (22.2mm) |
| 1/2" | 0.500" (12.7mm) |
1.250" (31.7mm) |
| 5/8" | 0.620" (15.7mm) | 1.500" (38.0mm) |
| 3/4" | 0.750" (19.6mm) | 1.875" (47.6mm) |
| 1" | 1.000" (25.4mm) | 2.500" (63.5mm) |