I discovered that there is a bug in the lathe version, regarding the G83 cycle.
The instrument collides for a few tenths of a millimeter (about 0.3) with the material at each stroke.
This defect appears only in the version of the lathe, because in the mill I have not encountered such behavior.
Can anyone check?
thanks and sorry for bad english, i use google translate.

Is the collision when the tool returns to the last depth ready to do the next peck cut?

I give an example:
G0 X0 Z1 (positioning in the instrument in rapid)
G83 Z-20 R0 Q5

Z-20 (total hole depth)
R0 (quick start position, setting value 0 will use Z1 as start)
Q5 (will make cuts 5 mm deep, to then exit the piece)

the first cut will be +1 (Z1) -5 (Q5) = Z-4
Arrived at the instrument Z-4 must go out (and this works correctly)
the problem in which it collides is the return!
in theory the rapid repositioning should stop about 0.25 mm before (therefore Z-3.75 )
Instead it goes beyond the last depth of cut (Z-4) !! it positions itself in rapid at about Z-4.3 !! then collides about 0.3 at each step !!

It practically reverses the calculation! instead of subtracting it!

I made a mistake writing in the gcode.
now I correct it.

G98
G0 X0 Z1
G83 Z-20 Q5 R1 F50
G80 G0 Z1
M30
;

the behavior is however as described, first lunge in Z-4
and in the version of the mill it is correct.
in the lathe version with the same code g the first cut is Z-3 !!!
wrong calculations !!!! generate collisions !!!
I also found anomalies with the G84 G84.2 cycles
the G76 cycle is also of mediocre quality.
am I the only one to find anomalies?
I want to understand if I'm making mistakes ??
none of you are detecting abnormal behavior?

Which motion controller are you using?

use the CSMIO / IP-S controller of CsLab.
I spent about 1400 euros between ardware and Mach4 license (not to mention the servo ac drive kit) and I have a mediocre system! : - [
what makes me angry is that with Mach3 it works well (although I don't like it because of the slow response times to the potentiometers).
Mach4 immediately fascinated me! so I immediately bought a license.
But to be honest, my problems have really started since I installed the Mach4 lathe.
I love it because I like it! but I often hate him for the problems he has!
4 or 5 years after its release it should be perfect or almost perfect !!

Poor plug-ins are often the cause, although manufacturers are reluctant to admit their limitations or mistakes.
except for the G83 which is an obvious Mach4 error, for the G84 and G76 cycles I think the cause is the plug-ins, I can't be sure because I'm not a technician, but a mechanic (each his job) so I can only hypothesize without certainties.

Hopefully Brett or Steve will chime in and comment on whether g83 is vendor driven or mach4.

It has been passed on to technical for there comments.  May be a few days due to holiday.

thanks, I had already notified parallel to the mail of the problem.
we hope they solve the problem.
I find that Mach4 is an exceptional program! deserves to work perfectly !!
I obtained splendid finishes thanks to the perfect functionality of the constant cutting speed !! thing unattainable by Mach3 !!
Come on Mach4 !!

At the moment still no answer.
in the meantime, none of you have done a test?
only I in the whole forum have this problem?