Cutter Radius Compensation / Nose Radius Compensation interference — showing up on lathes and mills alike, and driving good machinists crazy since forever.

Machinists usually fix it by reducing the D offset value, increasing the lead-in/lead-out length so the control can calculate the path, or reprogramming the corner/arc with a larger radius that the tool can actually clear.

If you look at the work offset screen on a Fanuc control, you'll usually see G54 through G59 listed. But right above those, there's a row labeled double zero or EXT that most new machinists never touch and don't understand what it does.

This is called the External Workpiece Zero Point Offset. Think of this as a master shift that adds or subtracts to all other work offsets. Whatever number you put in this one row gets added to G54, G55, G56 — all of them — at the same time. Normally you'd leave this at zero.

Instead of raising up tool offsets or individual work offsets, you enter the shift once in this double zero offset, and every work offset shifts together automatically. On the Z offset, type in 3.0 and input it. Now all of your program will run 3 inches (or 3mm) above the part.

Every time a tool gets loaded into the machine, the operator has to touch it off inside the spindle — burning spindle time on something that could've been done before the machine ever stopped.

Every machine gets a common reference tool holder, mounted in the spindle and touched off to the face of the table. That distance is recorded as a positive number in the Z axis of the double zero (00/EXT) offset — this becomes the machine's baseline reference point.

From there, tools are preset using a height gauge zeroed off that same common tool holder. The height gauge measures the distance to the top of each tool, and that distance is recorded as a positive number directly into the tool's H offset.

Because every tool is measured against the same reference point instead of being touched off individually inside the spindle, an operator can preset tools on the bench ahead of time and simply load the H offset numbers when the tool goes in — no need to touch each tool off inside the machine.

This allows tools to always be touched off outside the machine instead of inside the spindle. What used to take a few minutes per tool now takes five minutes or less for an entire job's worth of tools.