thanks again philobobb. when i use your post, the DRO Z height jumps all over when it applies the tool offsets. This test code uses tool 1, so 'load' the tool in Mach, zero the DRO and the dial indicator, cycle start, machine moves to tool change ok but looks to be applying the tool offset again when it moves from the tool change down to cut, happens when Mach executes the 'H1' command. Result is spindle wants to cut about tool #1 height above the zero for the test code (should be cutting at -0.5mm Z, not 90 something).