trim and tilt question

I want to do a tapper inside of a region where one end of the region is 0 or the top of the board and the other side is about 3/8" deep.
it appears the T and T rotates on the center or yellow dot along the length of the region. the slide arrow does not seem to give you to much control.
I can do it using extrude just not T and T, any advice

Works for me. Make a carve region 3/8" deep and then use the tilt.

you are the man!
here is the reason , made some spoons years ago and forgot how set it.
the end is too thin and shattered the end of the spoon.
Thanks again