Premium 1-2-3 Blocks & Attachment Hardware Kit

This set allows for joining the 123 blocks together with all the hardware buried withing the blocks (clean setups...) the hardware is also slightly smaller than the holes allowing edges and faces to be joined together with the faces being flush with each other.

Kit includes:

•  (2) matched blocks
• (4) Dowels
• (4) M6 Threaded dowels
• (2) M6 70mm Allen screws
• (4) M6 30mm Allen screws
• (1) hex key
• (1) M4 threaded knob

The 1-2-3 blocks (1"x2"x3") are parallel on all 6 sides to ±0.0001", flat within 0.0001" and square within 0.0001". They are ground and case hardened on all sides to 50-60 Rc. Each set includes two matched blocks.

The blocks have (23) 3/8" holes through them. To, use, insert a through hole dowel into a block hole and thread a screw through the hole. Next, insert a threaded dowel with the M4 threaded knob into a hole in another block and screw and tighten the screw into this nut to secure the two blocks together.

Each dowel has a straight screwdriver slot in line with the hole to assist in getting the dowels perfectly lined up to accept the bolts. An M4 thread knob can be inserted into the thread dowel to help in getting the dowels lined up to accept the screws.

These blocks have a myriad of uses, including, but not limited to:

• 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.  

Here is What to do with 1-2-3 Blocks by Rick Sparber that shows the many uses of 1-2-3 blocks,

• 1-2-3 Blocks Attachment Hardware Kit