https://www.youtube.com/watch?v=tywAByswH2Q&t=31sThis will show you the offsets page and the "Set Z", "Set Tool", and the "Toggle Height Offset" buttons.
I do not use the "Master Tool" method. I use the machine table as my reference, not the work piece; this way, as long as I haven't changed my tool (or reused the tool number in Mach4) I can use the tool at a later time and know that it is touched off.
Set each tool length by using the "Set Tool" button, use a Tool Setter or a Gage block to set your tools from the table, this will give you a consistent point to set your tools off to.
Be sure to change your tool number before pressing "Set Tool", you don't want to overwrite something you've already touched off. Just change the number in the tool number dro or do a tool change in MDI.
Once all your tools are touched off and stored into the tool table, you can set your Z Work Offset.
Select a tool. Be sure Mach4 knows what tool # you are using, then activate the tool height offset. G43H# or just press the Toggle Height Offset.
Touch the top of your part with the tool, then Press "Set Z" If you're using a gage block or shim, be sure to put that in the DRO for the Gate Block Height.