Dave,
Trying to use only one tool limits what and how you may be able to do things.The progression of machining steps
will vary but in the end the work gets done. Simplisticaly the thought process is just autonation and refinement of doing it manualy.
I use a quick change on my CNC lathe and serves me well. Just need to setup for tool change position and allow time to change tools.I KISS it by having home, referenced position, tool change position= Machine Coordinates 0,0,0 and define the G54 offset since my default G54 has no offset. Post cutoff off of a part one can just select another offset to make the same  part again if  you wish ....same gcode.

BTW, If I recall correctly G55 is used for rear mounted tool offsets, never mix front and rear tools in the tool table.
Hood can correct me if that is not correct.

There is no comparison of say LazyTurn to the higher end lathe programs, but, it can be a quick and dirty tool to learn and try different approaches to do work.
What is learned will have value in using the higher end programs.

Just something to think about...........,

RICH
 

Thanks

the idea or quest for one tool was not because of tool positioning etc - i have a QC tool post mounted and have 4-5 holders spare.

The idea was for simplicity - no tool changes is better than 1-2-3 changes (especially when you have no ATC) and with the tools i have seen available today, this part should be a walk in the park 

I have indeed learnt a lot - no cnc lathe use before, just manual, and yes as you say its just automation - the skill is getting the software to imitate what would be done manually, tricky as i just found out when there are a myriad settings to tweak.

I only have one tool post, as far as CAM goes, its just a normal front mounted post lathe, my post is rotated 90 degrees so the tools face backwards as the mount is to the Quill but apart from that its bog standard.

Yes i did read warnings about not mixing front/rear posts in the TT but thats not an issue here.

Ok so we have made a part (sort of) 

Spindle axis ePid faults wrecked it by stopping dead mid part-off, twice.

So i still have settings issues with my servo, anyone have any thoughts here??

This is generally triggered by the following-error counter reaching its max setting, currently 10,000 steps or 1 turn.

When it occurred, the tool was maybe halfway in the slot.

The rest of the part went perfectly, finish was 100%, facing off was perfect, just the last bit 

This problem has been there all along i think, pretty certain its the speed not a torque overload...

I can run ok up to 2980rpm, anything above that and the following-error runs away and it will fault out, same fwd and rev.

I have tried altering the voltage gain on the drive, tried altering the max speed on the drive

I can fudge it by setting Mach pulleys to 2980 but it seems some CSS code can get round that and will fault out when cutting as i found on my first run earlier.

I have tried other DAC channels on the controller, same.

Spent another day fiddling and got nowhere really.

Any thoughts???

...

BTW, If I recall correctly G55 is used for rear mounted tool offsets, never mix front and rear tools in the tool table.
Hood can correct me if that is not correct....
 

It is best avoided, from memory you need to restart Mach for it to behave or at least rehome.
The solution I used was to set ALL tools as rear tools(or front if that is your default), that means even front mounted tools were set as rear. Then when you want to use a tool from the non standard toolpost you would call a G51X-2 (X-1 if using Radius mode) and that would scale things to allow your movements to be correct for the X axis, you had to remember to call a G50 when you wanted to move back to the defualt tool post or things could get nasty. In the end I removed the front turret as it was just too easy to make a mistake and smack a tool into the stock. I made an 8 position  VDI turret up for the rear which meant swapping tools out was both quick and repeatable and I could have many tools preset ready for use.

Thanks for the reply Hood.

Did a quick look at front and rear tool post use since my recallection  was not stated correctly.

WORK OFFSETS are manipulated when both front and rear tools and offsets exist in the tool table.
G55 is manipulated as related to the G54. The Part and Program Coordinates change to reflect a distance
relationship of  front to rear tool.  That is the extent to which I explored the use of front and rear tool posts.

FWIW,
RICH

But any ideas why my spindle faults above 2985 rpm?

Afraid not, the servo I have on the Chiron is 3800 rpm, it runs at 3800 rpm and will not fault even if I called 10,00rpm as the max it will do is 3800 rpm. Kind of sounds like there is a drive issue with your setup but what that could be I have no idea.

Ok thanks Hood.

No idea what to do here really, i should just have bought a small CNC lathe i think, this add-on is killing me.

Today i replaced the cable that joins the drive to the controller, used proper twisted-pair servo cable (damn expensive) thinking it might be interference but no change at all.

I tried it at 2980rpm and it ran ok manually, i edited my code so the max CSS limit was 2980rpm and it passed three dry-cuts perfectly.

Feeling optimistic i put tool to metal and it actually made a part, tweak the tool offset to get size on, made another - OK.

Another tweak because i went the wrong way  and it made another part OK.

Run another and I get the ePid fault, it wasn't even running at max rpm i think, that is the point where i gave up and turned it all off, another 6 hours of messing and no result.

The parts are in the picture, apart from issues with stringy swarf, it worked really well which makes it even more annoying.

I was going to pull a drive from another axis but i have to pull the cabinet apart for that and i can't risk upsetting the main mill setup as i use it a lot.

At present it's half an inch or maybe 12mm away from the dustbin 

You mentioned earlier that the bearings were heating up, could it possibly be the increased friction of that is causing the motor to have a harder time keeping the spindle going and thus faulting out?