Rich,
first the reply by Andy. I decided not to question his reply and just asked to see a video of it working instead

The background of this is as follows. If using a single pulse for threading with an external motion device then it works well, usual caveats regards relatively stable spindle of course. If however using full encoder feedback to sync Z to Spindle then things are not so good.
The actual threading part works well on at least two of the devices I know that/have utilised it, the Galil and CSMIO, the DSMPC I am unsure how well it works. Where the problem is however is the end of each pass, the pull out is delayed whilst the plugin waits for updated info from Mach. There is no difference what you have the chamfer set to, well actually there is, the larger the chamfer the slower it
MAY be on the update.
The spring pass amount I fail to see how that could even be considered to be relevant.
I asked Dresda in another thread regards the pull out and it seems the DSPMC also suffers from this issue, not surprising really as the guy who wrote the Galil Plugin is Smurph who is also now on the Mach4 coding team, so you would think if it could be done he would be able to do it.
Now here is something I found purely by chance. There has been a change in Mach and the plugin interface. I had an earlier version of Mach loaded as I had been testing something else. I had forgotten it was loaded and when I tried the threading in a new CSMIO plugin it was great, pull out was almost instant but the spindle override wasnt working. It wasnt until later I put 2 and 2 together and realised that it was the older version of Mach that had made the difference in the pull out and not the plugin. Sadly Brian is too preoccupied with Mach4 to be able to say what the difference is and whether it could be added to later versions.
Good news however is when eventually Mach4 Turn is done things will be much better regarding the plugin interface and Steve (Smurph) has assured me he will make it a priority to have the correct code in there for lathe threading using full encoder feedback.
Hood