OK, so you have threading working in principle. Good.
Now to get the pitch right. This can be done.

I will assume you have have checked the calibration on your Z axis, so we will ignore that.
In that case, your chuck RPM is WRONG. It just has to be.

Possibility:
First of all, I am guessing that the index pluses are coming from the motor, not the chuck. If this is correct, and the pulley ratio is not 1:1, then the pulley ration in Mach could be actually the reverse of what it should be. Any joy here?

If the index pulses are coming from the chuck itself ... blimey. I dunno!

Cheers
Roger

Yep Z axis is good, but will double check it as not to look like an ass later.

Index pulses is mounted on spindle NOT motor - Sorry.

> Index pulses is mounted on spindle NOT motor - Sorry.
Mind-boggling.

And the pulley ratio in Mach is set to 1:1? Just checking.

Cheers
Roger

IF Z is accurate that ONLY leaves the RPM to be wrong. You said you checked it with a tach and the 2 were not together on rpm ? I would suspect the index signal card is bad. Could be missing signals OR getting noise.

Pulley RATIO should be at 1:1

NO debounce on the signal. If it needs the debounce then FIX the noise problem with a cap

Try setting the RPM with the Hand tach then cut a thread.

(;-) TP

If it was noise then I would have expected it to cut a different thread each time, I am able to shut the machine down rerun the code and have it perfectly ghost cut the original thread, I wouldnt have thought noise would have allowed this to happen.

As stated already, the LED on the C3 board is pulsing with each rotation, the LED on the input pin of the C32 is also pulsing, based on these two indicators I am not seeing any false triggers or intermittent pulsing, HOWEVER on the diagnostics screen of SS I am not seeing consistent pulsing of the input.

Can someone confirm that on there SS diagnostics screen they are seeing consistent pulsing? perhaps debouncing?

thx

Mine all works fine, although I did have problems when the SW debounce was switched on after a rebuild. At high speed (rpm) the pulses were too short to go through the SW filter in a consistent manner.

There has GOT to be an explanation somewhere!

Um - what happens when you try to cut a 1.0 mm pitch? Or a 2.0 mm pitch?

Cheers
Roger

I would simply turn OFF the use rpm for speed setting and do everything manually. Check the RPM with the Tach and set the program to run at that speed. THEN check the cut  thread pitch.

I would not trust the blinky led for anything important other than the switch comes on and off. At speed you will never see all the blinks.  Also your on period for the  signal may be too short and it misses signals at speed. The USE of debounce only makes this worse. IF your signal was clean you should never have to use debounce.


There are only 2 things that effect the outcome of your threads  Z axis moving the correct amount and true spindle rpm. Double check the Z calibration of steps per. Double check the calibration of your spindle RPM.

AND don't ASSUME anything.

Just some thoughts , (;-) TP

Hi Terry

I don't think Mach3 can use the RPM to control the speed when interfaced through a Smooth Stepper?

Otherwise, +1

Cheers
Roger

SS ?? AUURRG I did not see that Sorry.

But to be sure have you tried it ??  I do  know that mach3 LPT if you do not use Spindle sync it will assume the speed that you programmed it for and base the feedrate on that value.

At least it USED TOO long ago on a planet far far away (;-) ,

OK another thought, when you program an S speed and you check it with the TACH is it the same RPM +/- a few ??



 (;-) TP

Hi Terry

Yes, I tried to use Mach to servo the spindle speed. That didn't work, and one of the other gurus explained that the SS update rate is too variable to allow it to be done - so it isn't. I think Greg may have it on his to-do list for 'someday', as a feature to go into the SS, but not so far.

However, it seems that Mach3 is able to sync the Z axis with the spindle index pulse if it does do some averaging. There is a noticeable pause at the start of every cutting cycle when threading. But the threads it makes are good.

On the other hand, if you use spindle speed averaging, then the displayed RPM is very usable. So I went through the spindle speed calibration cycle (which is quite slow) and told Mach eventually to use the calibration curve for linearisation. That was quite successful - with averaging.

Cheers
Roger