Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 635)

Turning Operations
Chapter 18
18-19
The G34 single pass variable lead thread grinding mode grinds straight,
tapered, face, and multi-start threads that do not have a constant thread
lead. It is programmed almost identically to the G33 thread grinding mode
with the addition of a K word used to program the amount of lead variation
per revolution.
Figure 18.17
Variable Lead Thread
12076-I
The format for the G34 threading mode is:
Parallel thread G34Z__ F__ Q__K__;
E
Tapered thread G34X__Z__ F__ Q__K__;
E
Face thread G34X__ F__ Q__K__;
E
Where : Is :
X the end point of the thread grinding move in the X-axis. This parameter can be an
incremental or absolute and radius or diameter value. If not present there must be a
Z parameter. If an X parameter is present, it indicates either a face, tapered, or
lead-in thread. When used in a G34 block without a Z parameter, a facing thread is
made parallel to the X-axis at the Z-axis position prior to the G34 block. The initial
minor diameter of any straight or tapered thread is determined by the position of the
X-axis prior to the G34 block.
Z the end point of the thread grinding move in the Z-axis. This parameter can be an
incremental or absolute value. If not present there must be an X parameter. When
using a Z parameter in a G34 block without an X parameter the threading pass is
made parallel to the Z-axis at whatever X position the grinding wheel edge was at
prior to the G34 block. Z parameters are always entered as a radius values
regardless of the current mode.
18.2.3
Single Pass Variable Lead
Threading Mode (G34)