Running some test patterns to calibrate everything. No matter how deep I set the G-Code, Mach 3 only shows the z axis going to 0.10 inches depth. The actual travel is 0.18 inches depth.

I've run three different patterns, one at 0.10, 0.20 and 0.50. Ive read the code in the window to make sure that's what its set at and not that I haven't reloaded the new test pattern.

When calibrating the axis, the Z axis was perfect.

The Z axis isn't maxed out at the depths I'm cutting, it has probably 4 more inches of travel. This set up has a down draft table that eats up almost half the Z axis (I bought it from someone else built this way).

I've checked the guides, motor, threaded shaft and all are in good shape move smoothly, no binds, grinds, hesitation etc.

I'm thinking a setting I'm missing in Mach 3 since it stops at 0.10 indicated regardless of the G-Code but there has to be something else wrong with the actual depth being cut at 0.18 not that 0.08 is a lot in the grand scheme of things but in the CNC world I would imagine thats a lot.

Turn off the softlimits and try again.

I tried to follow this video but nothing changed.

When I click on the soft limits button on the screen I get a "Machine out of limits for soft limit activation"

Ill try to attach the screen shot of the motor/home soft limits page if I can figure it out.
Heres what is listed gfor the Z axis on the motor home limits screen since Im not sure how to load a pic here.

Z Reversed has a red X, Soft Max = 100, soft min was 0, I tried -4 like the video showed but no change. Slow z = 0.25, home = 0.000 Home Red X, auto zero green check, speed % = 20

https://www.google.com/search?q=z+axis+calibration+in+mach+3+cnc&oq=z+axis+calibration+in+mach+3&aqs=chrome.1.69i57j33i160l5.11084j0j7&sourceid=chrome&ie=UTF-8#fpstate=ive&vld=cid:c93d0c50,vid:xLUViu65qXg,st:102

How to set softlimits

For softlimits to work correctly the machine must be fitted with working home switches. 

If any axis is set to reversed in homing and limits this should be unticked and 2 motor wires reversed (A1, A2) for steppers and if servo drives the option set in the drive to reverse the direction.

Assuming all DRO's read minus moving away from home position set all axis as follows.

1. Home the machine.

2. Switch to machine coordinates.  Red ring around button indicated machine values.

3. Jog Z axis down so it touches the spoil board and make a note of the DRO value.  Jog clear of table.

4. Jog X axis close to its maximum travel.  Note X axis DRO.

5. Jog Y axis close to its maximum travel.  Note Y axis DRO.

6. In Z axis softlimit enter Z min as noted value and the Z max as zero.

7. In X axis softlimit enter X min as noted value and the X max as zero.

8. In Y axis softlimit enter Y min as noted value and the Y max as zero.

9. Re home the machine and turn on softlimits, yellow ring around button.

Some routers move plus from home on some axis in this case the min value should be zero and the max will be the noted value.

Note all axis must be set or nothing works.

The slow distance depends on the speed of your rapids, start at 100mm (4") and reduce until you can rapid to the limit without problems, when set correctly you will hear the machine ramp down to a slow stop as it approaches to the limit.

I appreciate the assistance, this is what I have.

Sending everything home (yes it has working home switches) at home the machine DRO settings are X +97.7686, Y -0.5016, Z 0.000, taking them to just short of their max travel X -0.8147, y +49.7205, Z -5.6850 ( I took the bit out in case that matters).

on th e Motor Home/Softlimits screen
X (Red X on reversed) Soft Max 97.77, soft min -0.81 slow 4.00
Y (red X on reversed) Soft Max 49.72 soft Min -0.50 Slow 1.00
Z (Rex X on Reversed) soft max -5.68, min 0.00 slow 0.25

I re-ran the square test pattern that's supposed to be 0.100 depth and it still drops do 0.30 depth on one pass.
I tried reversing the Z soft limits, turning them on and off (now I don't get the previous error when trying to turn on the soft limits so there is some progress!)

When the machine is at its home position the machine DRO's should all read zero. Make sure you have clicked the machine coords button to show the red ring around it.

Is the z axis home position at the top of the stroke?

Can you jog the the machine about in all 3 axis and it stops when the softlimits are reached?

How did you set your datum for the z axis?

Just getting a chance to get back to this. The Z axis 0 is at the top of the stroke.

On the machine coord for the DRO y and z are at 0, x is +97.7 (machine coordinates red light is on)

I can manually move the all 3 coordinates within the soft limits and it does stop as allowed.

Not sure what you mean by setting the z axis datum.

I spoke with another guy who has a shapeko, he mentioned the correct post processor. I mayhave been using the wrong one and found the MACH 2/3 post processor when creating the G-Code. Now the Go code has a bunch of N values in it. running the square test pattern, at 0.10" depth in one pass, it plunges directly to 0.20", running a 0.20" dept in two passes 0.10 per pass, the router makes one lap around the square, plunges for the second pass with an overall 0.30" depth. The second plunge is going as far as it is supposed to, just this first plunge going the extra 0.10.

thanks again for the help.

Finally figured it out. The VB code for setting the zero on the bit had the block as a 0.50 thickness rather than a 0.40 thickness. Made that change and it seems to be cutting correctly!

thanks for the assistance.