I am trying to operate Mach3 Turn and I am having an issue with it. The Diameter mode vs Radius mode acts as though it is confused. After homing and then touching off;

Diameter Mode, enter command G0 X0 or G1 X0 in MDI:
When I attempt to input the stock coordinates which I identify by skim cuts both Face and turn, I find that the X-axis movement is twice what it should be. In other words it never stops at the center of the chucked stock as it should, it will place the controlled point at exactly the diameter of the stock, 2 times radius.

Radius Mode, enter command G0 X0 or G1 X0 in MDI:
Will make the same move to the far side of the stock but If I attempt to run the job, the controlled point ends up at twice the radius. i.e. a radius of +.500 will position the controlled point to +1"

I have noticed that if I change from Diameter to Radius mode, the axis position according to the DRO is cut in half.

I have no problem with the Z Axis, all dimensions are accurate as expected.

Needless to say I have calibrated and checked the Axis motion and it moves the correct amount. Just not as directed by Mach3 Turn.

My question to you is just to get your thoughts on what might be causing this.

ESS attached to CNC4PC C82 BOB
The plugin I am using is ESS 2019_11_06 10wa-1of1
Windows 10
Mach3 R3.043.062 with Win 10 patch
Dedicated computer, 4 GB memory, Celeron N4120

I think the tool offset for X in the offset table has to be set as radius. Also do you have the turret front/back set correctly?

Could you be specific about what you mean by homing and touching off?  Generally if you touch a tool to a known diameter and type that value in the X axis dro with program coordinates selected, with lathe in diameter mode, everything should work.  Homing is only relevant if you are using tool offsets.

Hello Graham,
Thanks for the response. However, I did try again to be sure, but in my case it responds as in the radius mode:

Touch off and reference part coordinates, assume in this case that stock diameter is .500 inch
Move tool clear of stock
Enter command in MDI, G1 X0, responds by moving controlled point to stock center
Enter command in MDI, G1 X.5, responds by moving controlled point to 1 inch from stock center

Additionally, I do have it set as front post

Jim

Thanks for your response, homing is part of my startup routine. I have home switches so I reference X and Z axes and verify in machine coordinates that it is correctly at 0,0. In addition, I have an automatic tool changer. Tool 1 is offset 0,0 and the other 7 tools reference from tool 1

Well I can't think what you are doing wrong.  I only home X, so that X=0 corresponds to the cross slide being as close to the axis as possible.  Not much point in homing Z in my view as the position of the work is so variable depending on chuck etc.  I have a switch for X homing and set the X DRO to zero when homing is complete.  Once X is homed I have separate X offsets for all tools including tool 1.  I have a tool setter of known diameter and a calibration routine which measures the offset for a tool when it contacts the setter and writes it to the tool table.  I always have the lathe set to RADIUS mode for tool setting as the offset is a radius value.  Once the tool table is populated I restart in DIAMETER mode and everything works as expected.

Thanks John, I will try to emulate what you have done. A little extra explanation on how I look at home, Machine 0,0 as the most positive for each axis. I had a commercial machine and that was part of the startup routine.
Jim

So, assuming that X increases as diameter increases, your tool offsets are negative?

This is how I set may lathe.

It is fitted with a front tool post and is setup in diameter mode.

X axis DRO gets larger the further away the tool is from the spindle centre line.

Z axis DRO reads plus moving away from the spindle towards the tailstock.

1. Home the machine.

2. Select tool 1 in MDI T0101.

3. Move the tool to the work and skim down the front face. Do not move the Z axis.

4. Click to highlight the Z axis DRO. Enter 0.25mm in the Z DRO. Press enter, this allows 0.25mm to take off during machining.

5. Move tool to skim O/D of work and take a cut off the O/D, move back in Z axis only and stop spindle.

6. Measure diameter cut and enter it into the X DRO and press enter.

Touch each tool on the front of the work (do not take another skim cut) and enter 0.25mm in the Z axis DRO so all tools are set to the same Z datum selecting the correct tool number first. E.g. T0202, T0303 etc.  The X axis is set the same way by taking a skim on the O/D or scratching the tool 1 diameter and entering the measured diameter.

To John,

Thanks, for the master tool, there are no offsets, only the G54 fixture offset, at least that is how I am operating at the moment.

Jim