- Threaded holes are 3/8"-16 thread
- Through holes are 5/16"
- Hardened and precision ground steel
- Pairs are matched within 0.0002"
These precision 1-2-3 blocks are ground and case hardened on all sides to 50-60 Rc. The blocks are 1" by 2" by 3". They are parallel within 0.0002", flat within 0.0002" and square within 0.0002".
Each set includes two matched blocks.
The blocks have 23 holes through them, 5 are threaded 3/8"-16 NC, and the other through holes are 5/16" diameter.
These blocks are not designed to screw together. The unthreaded holes are smaller than 3/8". While this limits one rather uncommon use of the blocks, they have a myriad of other uses, including, but not limited to:
If you need 1-2-3 blocks that bolt together, get our P/N 6323 Blocks, 1-2-3, Universal 11 Hole Set, but if what you really need is an angle plate, get one. They are cheaper and easier to use. Here is What to do with 1-2-3 Blocks by Rick Sparber that shows the many uses of 1-2-3 blocks,
- Use as parallels: Set your large workpiece on 1-2-3 blocks and clamp it to the table so you can drill through holes without damaging your mill table.
- Use as fixtures: 1-2-3 blocks can be clamped to a machine table and used to create a repeating set-up for machining identical parts.
- Check your calipers: Since 1-2-3 blocks are made to tight tolerances, they can be used to verify the accuracy of your calipers.
- Use for measuring: Hold a 1-2-3 block against your workpiece to make a protruding edge that you can measure to.