Problem with undercutting

[jscott6SWZG]

I am unclear about how to set the top height for an undercut.....by trial and error I discovered that you enter model top with an offset of the tool height.

If so why doesnt the program pick up the flute length from the tool cutter settings????

[a.laasW8M6T]

Yea its a little confusing

I set the top height as the top of the slot, with a negative offset of the difference between the flute length and the maximum step down value.

so for example if you had a 2mm thick slot cutter with a 1mm stepdown you would put in  an offset of -1mm

or if the max stepdown was 0.5mm then the offset would be -1.5mm