Threading does not start

Hi guys,

First of all I'm a complete newbie with linux cnc, I've just finished the mechanical conversion of my lathe to cnc and i'm trying to see if I can do spindle sync. Last weekend I've managed to sync the Z axis with the spindle encoder, so the encoder is fine..but since then, I've messed up something and I don't know exactly what.
Now, I'm trying to do some air cut threading just to see that the synchronization works, it does move the axes into position but the thread does not start.
I've checked with the HAL Meter, and I can see the encoder index signal.
In the picture below you can see how my screen looks like..if you notice anything unusual, please let me know;
goo.gl/photos/cNutMtBCD7venhTG7

I think the three things required to start spindle synchronized motion are

1. Spindle index working and your hardwares index enable wired properly in hal to motion.spindle-index-enable
2. Same for spindle at speed
3. Encoder scale set correctly and in the correct direction (counting up by +1.000 every spindle rotation)

I don't know if you had the chance to see the picture, but the spindle at speed LED is green.
I have not made any changes in the files other than from the UI.
I've inspected a bit the files that get generated after doing the settings and noticed that at some value (can't remember its name now), the value in the file was 1440 and my encoder has 360ppr, so I suppose its counting both falling and raising for both channels.
The speed of the motor of my lathe is controlled via a knob, I can't control it from software, at least not yet.
Does this matter for the settings I'm making from the UI?
The fact that I got it working once, tells me that I'm quite close.
If you have the time to see the picture from the link above, that may give you any clues on what I might be doing wrong.

Do you have a feed rate set and spindle rate.

F350 S400

I had trouble with that at first the spindle speed needs to be near the S rate

Also as have been stated the encoder must be counting it the correct direction.

Finally got it working!
The the generated code was M3 for clockwise and my manual lathe is counterclockwise. I've added M4 S160 and I've managed to get it working!
I've been waiting a lot for this moment!
Right now I'm running through parallel port, and I can see that at some point the motors sound different for a split second and the UI freezes a bit.
Hopefully, when Mesa 7i76e will arrive I'll be free of these issues.
Thanks guys, I could not have done it without you!