SPI 13-669-7 0.0001in Squareness 5/16-18 Tapped, Matched Pair 1-2-3 Block Set
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The SPI 13-669-7 is a matched pair of hardened steel 1-2-3 blocks — nominally 1 in x 2 in x 3 in — ground to a squareness tolerance of 0.0001 in, making them suitable for precision layout, inspection, and workholding setups on surface plates, milling machines, and grinders. Each block features multiple through-holes and tapped holes sized 5/16-18 UNC on all faces, enabling clamping, bolting, and fixturing in multiple orientations. The set includes five socket head cap screws and a hex key (Allen wrench), and is stored in a fitted red plastic carry case as visible in the photos and confirmed by the label reading '13-669-7 / 1-2-3 Blocks / 0.0001 w/ plastic case'. Both blocks are supplied new and are matched as a pair to ensure consistent referencing when used together for squaring vises, indicating part datums, or supporting irregular workpieces.
Product Specifications
| Brand | SPI |
| MPN | 13-669-7 |
| Block Nominal Dimensions | 1 in x 2 in x 3 in |
| Squareness Tolerance | 0.0001 in |
| Tapped Hole Size | 5/16-18 UNC |
| Quantity | Matched pair (2 blocks) |
| Included Hardware | 5 socket head cap screws, 1 hex key |
| Case | Fitted red plastic carry case |
| Material | Hardened steel |
| Condition | New |