trouble homing before program starts (lathe 2 axis)

[StonewalLee]

I am new to CNC and so far i have been able to get really good help on the forum and especailly Marty. MY problem is when i start up the machine i home it, Then i come in and i zero everything (meaning my part zero). When i actually go to run my gcode the machine homes itself and then the program begins but this time it doesnt go all the way back the touch the limit switch. Because of this i am always off the same amount its maybe like .300 ". Am i maybe misunderstanding what it is doing? Neither axis actually goes all the way back to trigger the switch, and i was thinking its maybe something i did in the homing wizard. (as far as the using the wizard to setup my homing, i just check the box that builds a homing program automatically.)

Let me know if it would be better to just send a video or something

[tblough]

Without posting a report or your g-code to know for sure, when you start a program the machine does not go home. It goes to the tool change position (G28) that you have set as return point #1.

To adjust the return position, F1 Setup/F1 Part/F9 WCS Table/F1 Return then set the Z and X values for Return #1 (G28). On my lathes with QC toolposts, after I set my Z and X zeros, I move the tool a comfortable position away from the part and then set the return position to that point. I do this for every program.

Some people prefer not to have to set it for every program and instead set the return point near the far end of travels away from the chuck. The downside to this is having to wait for the carriage to traverse the distance for every tool change and at the beginning and end of the program.