Spi 13-670-5 1-2-3 Setup Block 23 Hole Matched Pair

Product Description

The SPI 13-670-5 is a hardened steel 1-2-3 setup block sold as a matched pair, designed for precision workholding, fixturing, and machining setups on mills, grinders, and surface plates. Each block measures 1 inch by 2 inches by 3 inches and holds a squareness tolerance of 0.0001 inches per inch, making it suitable for applications where parallelism and perpendicularity are critical. The block features 23 total holes — 5 tapped and 18 untapped — along with 3/8-16 tapped hole threads for clamping, stacking, and fixturing configurations. Hardness is rated at 55-60 Rc. Machinists, tool and die makers, and precision fabricators use these blocks as reference and support tools during layout, inspection, and milling operations.

The SPI 13-670-5 matched pair is suited for machine shop environments where repeatable, accurate workholding is required. Common applications include supporting workpieces during surface grinding, establishing parallel references on milling fixtures, and serving as gauge blocks for inspection setups. Sold as a matched pair, both blocks are held to the same tolerance specifications, allowing them to be used together for stacked or mirrored setups. The 23-hole pattern provides flexibility for bolt-through, clamping, and dowel-pin configurations across a wide range of fixturing needs.

Key Features

• Squareness tolerance of 0.0001 inches per inch for high-precision setups
• Hardened steel construction rated at 55-60 Rc for wear resistance and dimensional stability
• 23 total holes per block: 5 tapped, 18 untapped
• 3/8-16 tapped hole thread size for standard clamping hardware compatibility
• Sold as a matched pair, both blocks held to the same tolerance grade
• Standard 1 x 2 x 3 inch profile fits common fixturing and gauging workflows

Compatibility

Designed as a standard 1-2-3 setup block for use with common milling machine tables, surface grinders, and surface plates that accept 3/8-16 threaded clamping hardware.

Installation Notes

1-2-3 blocks are typically handled by machinists and tool and die makers during machine setup and inspection operations. Ensure all contact surfaces and the machine table or surface plate are clean and free of burrs or chips before placing the blocks to avoid measurement error or surface damage. Secure clamping hardware snugly and verify squareness with a dial indicator before committing to a cut. Do not use these blocks as striking tools or drop them, as impact can compromise hardness and dimensional accuracy.