[htraps]

How does one set the endmills to the correct depth during tool changes? I require 6mm roughing and 3mm finishing passes.

I can only think to add collars to the endmill but will that throw off the balance too much?

You can but endmills with colour coded collars which look great but don't use the same shaft diameter which would be preferable nor do they look to be even set to the same distance.

How do people achieve tool changes?

[peteeng]

Hi Traps - Usually I reset my Z zero every tool change. But collars would work if the grip length of the tool and the stick-out are similar enough to allow the collar to work. Plus if the job at hand doesn't need the tool length. Peter

[CitizenOfDreams]

There is nothing wrong with plastic collars (AKA depth rings). If you can't find them in your size, you can easily make your own (you do have a CNC machine, right?).

As for the distance, just set the ring so that the tool is properly engaged in the collet. Then you have two options:

1. Reset the Z axis after every tool change.
2. Measure all your tools, add them to the tool table and use tool length offsets on your CNC controller.