CNC Machinist Calculator UltraG34 Variable lead thread cutting
Fanuc G-code · Lathe
Cuts a thread whose lead grows or shrinks by a set amount each spindle revolution. Used for special screws and feed worms.
Format
G34 X(U) Z(W) F K
Addresses
| Address | What it does |
|---|---|
X Z | Thread end point, X as a diameter |
F | Lead at the start point |
K | Change in lead per spindle revolution, plus or minus |
How it works
Modal, group 01.
Example program
G97 S300 M03 (CONSTANT RPM)
G00 X1.95 Z.5 (START POINT)
G34 Z-3. F.25 K.002 (LEAD GROWS .002 PER REV)
G00 X2.2 (RETRACT)
G00 X1.95 Z.5 (START POINT)
G34 Z-3. F.25 K.002 (LEAD GROWS .002 PER REV)
G00 X2.2 (RETRACT)
Example is in inch. Check offsets and clearances first.
Watch out for
- Check that the lead never goes to zero or negative over the length.
- Use G97 constant RPM, the same as any thread.
Related codes
G34 on other controls
The same number can mean something different on another control.
| Control | Meaning |
|---|---|
| Okuma OSP | Variable lead thread, increasing |
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