Z axis moves below set zero

I doubt its moving that far I think it may be out but he obviously has not RTFM and in other threads has claimed similar which is where we got to auto tuning as simpler than trying to get information required to do calculations for him. Over several different threads its obvious he doesn't quite understand how Mach works when told its definitely tuned right I tried to point out margin of error that would be required so used 2540% to emphasize enormity rather than 25.4x to attain the results claimed.
I would imagine set z Axis zero to top of table rather than top of material as his sole piece of G-code never goes negative or below 1.5mm, just difficult to get information to help would guess all being done from his phone with the minimal responses.

Once motor tuning is complete, if you don't confirm moves with a dial gauge you're on a hiding to nothing.
I'm always surprised by how many take the "Red to red and black to black, throw the switch and stand well back" approach to engineering fault finding, I bet half of them can't count as far as 10 with their shoes and socks on ;-)

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Originally Posted by magicniner

Once motor tuning is complete, if you don't confirm moves with a dial gauge you're on a hiding to nothing.

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I'm a bit surprised that you said that. I would have thought that, given that you should know to the limit of manufacturing accuracy everything you need to calculate the "steps per unit" figure, calculating is the best way to get the right number to put into the configuration page. Yes, by all means check it afterwards, but even on my crumby old MDF machine, a quick check with a rule was enough to make sure that I had, for example, set the right micro-step value on the drivers. Any error will leap out at you - you are likely to be a factor of two or more out, not some small number of per cent (and assuming that you double-check your sums and data entry, of course). Any error so small that you could only measure it with a dial gauge is looking for design or build errors - too much backlash, not properly tightening the locking nuts on a bearing holder, or something like that. And in this case, you are checking that the dial gauge returns to the same value when you have moved off zero and then back again, not measuring travel. You will probably even check for missed steps by a "return to zero" test, rather than measuring travel. The idea mentioned elsewhere in this thread that you get the "steps per" value by measuring it suggests that the builder/operator doesn't actually understand how the machine works, and that is a worrying idea.

But I might have misunderstood, and if so I'm happy to be corrected. Always willing to learn!

On a different point, unfortunately, this thread has been riddled with typos (from the OP, it has to be said) that make many of the questions really difficult to understand. Please, please, read through any post before hitting "post" and make sure that it reads correctly! Predictive spell checkers really don't understand CNC terms and concepts and can't be trusted to get it right...

My point is that so many half-informed attempts are made without a clue that double checking is always a good idea, even if you think you got your maths right, before assuming your software or hardware is broke because things don't do what you want.
I would never run a mill without checking some moves with a pointer on a rule then with a dial gauge and blocks, some might trust that the pitch of their screw is perfectly as advertised, I like to check actual movement.

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Originally Posted by Neale

this thread has been riddled with typos (from the OP, it has to be said) that make many of the questions really difficult to understand. Please, please, read through any post before hitting "post" and make sure that it reads correctly! Predictive spell checkers really don't understand CNC terms and concepts and can't be trusted to get it right...

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At times I've wondered............

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Originally Posted by magicniner

I would never run a mill without checking some moves with a pointer on a rule then with a dial gauge and blocks, some might trust that the pitch of their screw is perfectly as advertised, I like to check actual movement.

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Couldn't agree more on checking. Can't tell you how many times I've seen cheap drives with wrong Dip switch markings.
However to get the OP issue they would have to be massively wrong. Plus Mach's Auto Steps per option does a very good job of getting right provided accurately measured.

What his problem is I've no idea because is replies are much use fart in space suite.!

I have ajuster the motor tuning its not perfect but very close.now when I move the dro it's movement matchs the z axis.I load g code move the torch to the top of the materal zero all the axis press reg move up the z from the materal the run the g code .the torch will move down to materal then carry on down toward s the table then eventually will start to cut

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Originally Posted by whensparksfly

I have ajuster the motor tuning its not perfect but very close.now when I move the dro it's movement matchs the z axis.

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Told you this before The steps per is not something that you tune or tweak. It's Calculated and Fixed number based off mechanical and Drive parameters.
Motor tuning and Steps per are completely different things. Motor tuning won't make the machine move wrong distance.! (well it will if over tuned but that would be missed steps and very small amounts)

Your replies are not helping us help you.!! . . Be more clear please. Comments like " zero all the axis press reg move up the z from the materal" don't help tell whats happening or not.

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Originally Posted by whensparksfly

press reg move up the z from the materal

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Turn off predictive text and read before sending!

Just forget it just because my spelling and I'm not great at explaining things thanks for making me feel stupid I not be on this forum again

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