Simply use Mach's 'spindle' to run the 4th axis and just operate the router off a manual switch (or via a relay if you want CNC control).

Thanks,
But my router is controlled through a Vfd and would run at 18000rpm all the time.

What I would like is the opposite ,ie the rotary axis ran at max speed and then be able to control
the router spindle speed.

Iam thinking about just conecting a simple single phase motor thru a series of pullys to the 4th axis and
some way of disconecting the belt so I have a indexer and a lathe spindle,not high tech,but it should work.

Regards
Whatda

Steve, could you post the gcode just for an example on how to do it. No need to add comments.
Thanks
Bob

whatda: My 4th axis is being made into a standard part of a larger new machine being devoloped now. For that project, I am developing a hardware 'swapaxis' that will work outside Mach so that my 4th axis is not tied to using Mach. There are also other people who want the 4th axis and do not use Mach3. That may do the trick for you.

Also I am deveoping a 'Super Duty' version of the 4th axis which has a 'back gear' double reduction belt setup for heavy simultaneousl 4 axis milling and for high toque applications like drilling large diameter holes in the center of tough material or turning large diameter stock. The high speed capability remains and switching between the two is a simple belt move. You may be able to do something similar, but swap motors instead of reduction sets. I'll be posting videos soon on Youtube when the new 4th axis is finished so you can see how it is set up.



stnc: What is it exactly that you want to know how to do? The swapaxis function is part of Mach3 and is not done in g-code. I wrote a pair of macros to call it. You call the macros from G-code using the 'M' command. It that what you are after?




             

Steve,  that's right. I don't know how to call the macro.
Thanks
Bob

As an example, my macros at issue are the following. I have posted the macros previously, but if you can't find them, I'll be happy to post them again. Note that the numbers are not special, you can use any unreserved number you want:

M951 initiate swap axis (A axis becomes Spindle and Spindle becomes A axis)
M950 Cancel swap axis and re-home the A axis

M961 apply spinfle lock (just activates an output that I have controling a relay which in turn controls a solenoid valve which in turn operates the air cylinder)
M960 release spindle lock

Example of G-code would look like this (Note that 'M' codes call external macros):
N50 M951 (initiate swap axis)
N55 M3 (turn on spidnle)
<add your turning code here>
N65 M5 (turn off spindle)
N70 M950 (un-swapaxis and re-home A axis - note that the A axis has lost its reference due to being a spindle, so re-home puts it back to a known zero)
N75 G0 A45
N80 M961 (engage spindle lock)
<cut a tooth, drill a hole whatever>
N150 M960 (release spindle)
N155 G4 P.1 (delay *might* be needed depending on how fast the lock is vs your accell of the A axis)
N160 G0 A90
N165 M961 (engage spindle lock)

etc, etc

Thanks alot Steve, thai's what i needed.  Good luck on your up coming project.
Bob

Update on the swapaxis question: the third of my little PCB projects is now complete and tested . . .

The new 'SWAPAXIS' hardware board is completed and working!

This should work with any CNC software and also with the Smoothstepper. The rehoming macro still works, but the swapaxis command is now superfluous, of course and will be removed.

I extend an offer to Hood, who has helped me a lot with my projects, to receive a free swapaxis board to keep in exchange for testing it with smoothstepper. If Hood declines then the offer is open to anyone with a smoothstepper who is willing to do some testing.

I am currently accomplishing the axis swap via the M9 command for flood cooling. I have the output mapped to the SwapAxis board. ANY output will work fine, I just used a 'standard' CNC output that every system should have available.

Photos of the little PC board follow. The .032" end mill I normally use was too wide for the very small traces needed for this little guy, so I did my first rounting with a 30 degree router bit to cut the traces. NOw I have 'ebgraver fever' and I want to engrave everything. Trying to figure out how to fixture the dog . . LOL!!

Simpson, looks good
Thanks for the offer but I am not sure whether I can use this or not.  I use differential Step/Dir signals and the board I made for that connects direct into my BOB (see pic)
I presume your board just accepts single ended step/dir inputs?
Hood

Hood, every time you speak, I realize how much I have to learn 

I am aware of differential signaling being used for encoders (I use that myself), but are you saying that your servo drives also use differential step and direction signals? Does smoothstepper support differential step and dir signals?

My board does not really 'accept' anything, it is just a signal switcher.  It would not have enough lines for differntial signals, but I suppose you could use two of them. I don't think I would be inclined to pursue that unless your setup is common. I have not heard of using differential signals for step and dir. What would be the purpose except to mount the drives far away from the BOB?