Use 1-2-3 Block on Finished Face of Part

This approach is similar to the method described in Chapters 4 (Coordinate System) and 6 (CNC Operation). You must have a clean part face to begin with.

1. Face Mill Part

Begin by installing an end mill or face mill in the spindle. Follow all safety precautions. Start the spindle, and manually jogging the tool close to the top of the rough stock. Reduce the job increment to .001 inches per pulse and slowly move the tool down until it just contacts the face of the part. Then move the tool off to the side of the part and then lower the tool by the amount of the face cut (usually .005-.02inches). Increase the jog increment to .01inches per pulse and move the tool in XY as necessary to create a flat surface on the face of the part.

2. Stop the spindle

Stop the spindle before proceeding! Jog the tool well out of the way so you do not bump it with your hand or head.

3. Place 1-2-3 Block on Face of Part

Make sure there is no coolant or chips on the face of the part. Place the 1-2-3 block on the face of the part.

4. Jog Tool Alongside 1-2-3 Block

With the spindle OFF, carefully jog the tool until it is along the side of the 1-2-3 block.

5. Raise Spindle While Pressing Block Against Tool

While applying SLIGHT pressure against the side of the tool, slowly raise the spindle in .001 inch increments until the tool JUST slips between the top of the part and the end of the tool. You must set the tool length based on the longest tool flute, so move the block out of the way, rotate so the next flute is pointing towards the block, and then try to slide the block underneath it. If the flute is longer than the others and the block does not slide beneath using slight pressure, raise the spindle in .001 inch increments until it does. It is not uncommon for flutes to vary in length .005 inches or more. Repeat until all cutting flutes have been checked.

6. Set the Tool Length Register Value

Set the Tool Length Offset register at this value. This is done on the Haas by pressing the TOOL OFFSET MESUR button (beneath F1). Other machines may require you write down the Z-value reading on the CNC control and then enter this value in the tool length register for this tool.

7. Adjust For the Length of the 1-2-3 Block

Since all tools are set 1, 2 or 3 inches (depending on which side of the 1-2-3 block used) all offsets must be lowered by this amount to adjust them downward to the top of the finished part. There are two ways to accomplish this: