[TheDude]

Another few questions.
Hobby cnc 4 axis kit.
-How reliable is the readout in the mach3 software for using it as the DRO?
-Does the mach 3 software have a backlash setting like in kcam?
-Do the motors turn fairly free for manual machining?

Thanks again

Steve

[LeeWay]

The Dro's in Mach are as accurate as you set them up to be and as your machine can handle.
They won't actually work in the typical sense for manual milling. Say with the handwheels.
The motors are easy to turn with no power applied. They lock up to their holding torque when you apply power.

To use Mach 3 with a semi manual mode is easy to do using the MDI page. Type in where you want which axis to go and hit enter. In this case, the DRO's are accurate again as close as you have them set. Use the keyboard for manual milling instead of the handwheels.

Mach 3 does have backlash compensation, but I am unaware if it actually works when using the MDI screen or when using the jogging tab. I do know you can set it and it will work when running a program.

[TheDude]

So there is no way to have the steppers run free while manually milling with the handwheels while watching the position on the screen?
Sounds like I'll soon learn that manually typing position and feed rate would be easier?
But why do they advertize that "You can still use your handwheels with these motors"

[ger21]

The DRO's correspond to the steps sent to the parallel port. It's possible to use encoders and create DRO's to display the encoder's positions. You'll need to modify the screens.

[LeeWay]

As Gerry said, encoder's attached on the motor or handwheel should make the DRO's work, but then I'm not sure about how they would work when still under power. Seems it would still be tough tyo turn them unless it was only the encoder's that were powered.
You can use handwheels for manual milling, you just won't have the Mach 3 DRO's with the typical stepper setup.

I do a small amount of manual milling with my mill. It doesn't have handwheels, so not really manual milling in that sense. I use the keys to jog and mill. I leave the jog set at about 5% and run the X and Y axes like that. If I need to make a faster move, I hold down the Shift key and use the jog arrow. This lets it run full speed.
I typically use the MDI screen for more precise depth settings on the Z when I am doing this.
Most guys find they never touch manual handwheels after you sink your teeth into Mach 3 a little more.
I had them on my router, but removed them as they seemed a safety hazzard and were redundant with Mach.
They are useful before you get a machine powered up though. Setting limit switches, finding travel extremes and things, but these can also easily be done with Mach in charge.

[ger21]

As Gerry said, encoder's attached on the motor or handwheel should make the DRO's work, but then I'm not sure about how they would work when still under power.

You'd need a different set of DRO's on a custom screen. The regular ones only work with outgoing step signals.

[TheDude]

Sounds like it would eventually be better to use the MDI to locate for my next feature as I get more comfortable with the software.
I was hoping to avoid buying a DRO kit and it sounds like I would only need one if I wanted to operate the mill manually.
So when you are finding an edge with an edge finder. Can you manually jog each axis by .001" then zero the location in the mach? Then jog half the dia of your edge finder, rezero and you have your origin?

I'm sure these are questions I would soon learn when operating the mach. I'm just curious to the level of "manual" control I have with the jogging controls.

Thanks again guys, very helpfull.

[ger21]

Can you manually jog each axis by .001" then zero the location in the mach?

Yes.

Then jog half the dia of your edge finder, rezero and you have your origin?

You don't have to do that. Just click the button on the offsets page and Mach will set it for you.

[TheDude]

Thanks again guys. Look forward to sinking my teeth into this facet of the machining hobby..

[Pader]

So there is no way to have the steppers run free while manually milling with the handwheels while watching the position on the screen?
Sounds like I'll soon learn that manually typing position and feed rate would be easier?
But why do they advertize that "You can still use your handwheels with these motors"

I don't know if you are aware of it Dude but the rating of a stepper motor (pounds/ft, KG/Metre) is an indication of the HOLDING torque, not the cutting torque and so, when you have power applied, you will be fighting that holding torque, Motors will turn easily when there is no power present.

[RTTIM]

i have a pendant controller for my mill that lets me do manual milling under Mach3 control - they're not all that expensive....you might check it out.

If you're talking about some occasional simple milling that you don't want to take the time to set up for cnc, you can always use one or two long travel dial indicators with mag bases,

As others have said, you won;t be able to easily turn the screws against the stepper's holding torque so you'll likely need to unplug the steppers to mill manually.. Also keep in mind that if your machine has been converted to ball screws, they don't have the friction of the standard screws and will move much easier - even when you don't want them to.

Personally I like the pendant approach. It takes a little getting used to, but lets you manually mill quite effectively with the advantages of still operating under Mach3 control.

[CitizenOfDreams]

I personally pretty much abandoned manual milling. Takes me no longer than a minute to make a simple shape in CamBam and output the G-code file.

[RTTIM]

I personally pretty much abandoned manual milling. Takes me no longer than a minute to make a simple shape in CamBam and output the G-code file.

Same here. I also find find that the Mach3 wizards let you quickly set up many jobs that would normally be done manually.

Still once in a while I run into something, mostly when modifying or repairing something. Just the other day I had to widen a clearance slot in a part for a bolt head - clamped the part in the vise, quickly zeroed it in. and then used the pendant to manually control the cut. The whole process didn't take more than a couple minutes.

[dharmic]

I find the lagginess and extra steps of jumping into the wizards, generating code, coming out and running it to be a PITA for simple stuff. And running back and forth between the CAM on my computer in the house and the machine in the shed gets tired for simple things too.

For me, if it's simple shapes that are combinations of arcs and lines, I'm pretty happy to just enter the g-code manually on the MDI interface. It's quick and easy once you get your head around the g-code and that learning has big advantages in checking CAM output code, altering POST configs, writing custom Mach macros etc.

[coherent]

I use a Vista CNC pendant. Easy to specify jog steps or speed and IMO the simplest way to "manually" mill simple cuts or surfacing.