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G76 Threading
Drive Line - A line through the initial X position parallel to the Z.

P- - The thread pitch in distance per revolution.

Z- - The final position of threads. At the end of the cycle the tool will be at this Z position.

Note
When G7 Lathe Diameter Mode is in force the values for I, J and K are diameter measurements. When G8 Lathe Radius Mode is in force the values for I, J and K are radius measurements.
I- - The thread peak offset from the drive line. Negative I values are external threads, and positive I values are internal threads. Generally the material has been turned to this size before the G76 cycle.

J- - A positive value specifying the initial cut depth. The first threading cut will be J beyond the thread peak position.

K- - A positive value specifying the full thread depth. The final threading cut will be K beyond the thread peak position.

Optional settings

R- - The depth degression. R1.0 selects constant depth on successive threading passes. R2.0 selects constant area. Values between 1.0 and 2.0 select decreasing depth but increasing area. Values above 2.0 select decreasing area. Beware that unnecessarily high degression values will cause a large number of passes to be used. (degression = a descent by stages or steps.)

Q- - The compound slide angle is the angle (in degrees) describing to what extent successive passes should be offset along the drive line. This is used to cause one side of the tool to remove more material than the other. A positive Q value causes the leading edge of the tool to cut more heavily. Typical values are 29, 29.5 or 30.

H- - The number of spring passes. Spring passes are additional passes at full thread depth. If no additional passes are desired, program H0.

E- - Specifies the distance along the drive line used for the taper. The angle of the taper will be so the last pass tapers to the thread crest over the distance specified with E.' E0.2' will give a taper for the first/last 0.2 length units along the thread. For a 45 degree taper program E the same as K

L- - Specifies which ends of the thread get the taper. Program L0 for no taper (the default), L1 for entry taper, L2 for exit taper, or L3 for both entry and exit tapers. Entry tapers will pause at the drive line to synchronize with the index pulse then feed in to the beginning of the taper. No entry taper and the tool will rapid to the cut depth then synchronize and begin the cut.