You may run in to issues with that as well. What will likely happen is the spindle will slow but the drive then compensates, which sounds good. Problem is Mach has seen the slow down so it too compensates by slowing the axis but by that time the spindle has recovered so Mach has to try and compensate again and very likely can not.

Hood

Thought you might like this TP.
Someone asked me if it would work so I tried it today.
https://www.youtube.com/watch?v=0-KlHFYxzkM

SWEET!

Now I know what to ask Santy Claus for this year.

I like that one Hood,

Years ago, at least 8 years or so, you could slave the Z axis to the spindle when using IMS software ( used an encoder) for threading and do what you showed. What was sweet was one could repair a thread or even just use "manual" spindle power to cut a 0-80 and the
thread would come out perfect.

Maybe someone will figure it out for Mach 5......

RICH

Actually one can do THAT magic trick with Mach3 IF you are very very clever.

Just a thought, (;-) TP

You have me a bit confused TP, first you say

Finally someone has threading on a small lathe down to a science.  They have the Z synced to the spindle as it should be by encoder. AND it works(;-)

Then when it has been pointed out that it has already been done for many years with all sorts of hardware/software, you now say.

Actually one can do THAT magic trick with Mach3 IF you are very very clever.

So take it I can look forward to a video from you of Mach3 doing a thread via the parallel port and then you disabling the spindle and running over it again by rotating the spindle by hand?

Hood

Rich, I think Art was saying it should be possible in Darwin but maybe I am not remembering correctly. Anyway works fine with Mach3 if you have the correct controller or with other software such a LinuxCNC or as you noted IMS.

Hood

Art suggested  it could be done, but, would require a complete testing similar to what was done for threading.
It was requested or suggested but effort required probably wasn't worth the volume of use. That was a rather long time ago.

Terry may have some thoughts on being tricky. If you slave the Z to the spindle you can machine scrolls around a cylinder
with live tooling ( I was using a stepper driven spindle ). Never tried using an MPG to control that total movement, the "cloud" above my head says
it should work, but, may be more a PITA, than it is worth doing.

FWIW.
RICH

Hey Terry,

Still have some pages left in my screen set.
Feel free to fill them up.

RICH

Yous guys are funny. I said magic trick and that is what it would be(;-). Art did say it was possible in m3 but never would reveal the secret. I think For fear of the kaos it would create with everyone try to do it. More support. I think I figured out his secret.

THink about an MPG. You can simply and accurately drive the Z with an MPG correct ?  So if the Spindle was the mpg(encoder) AND you did the math correctly to match rotation of the spindle to movement of the Z you have the magic trick. I did BUILD the basics and it would do exactly what you saw Hood do. And in respect for Art that is where I stopped with it.

And yes it is easy with a step/dir spindle either stepper or servo.  You can make it deadly accurate with a servo spindle by having it do indexing as well. Then you can Sync the spindle rotation to the Z axis motion through a MATH channel. THEN the spindle rotations will folllow the Z no matter where it goes. I have done THAT as well in TURN AND in MILL. THE Torus mill that comes with a servo spindle , I help develope a rigid tapping scheme that not only does rigid tapping BUT USES mach3 Gcode canned cycles to do tapping. THAT was the magic trick. The spindle could do RPM or indexing without SWAP AXIS or flipping a switch. You could command EITHER from Gcode.

There ARE still some secrets in the DIY world (;-) Not ALL the cats have gotten out of the bag.

(;-) TP