I ran out of head space on my mini mill and needed to tap some holes after they were drilled.
I prefer to do it right after drilling so everything is always lined up. My 1/4-20 tap likes to slip in
the chuck on my mill so I just went to the tried and true method of using a "center" to line up the tap.
This is not as good as a tap follower but that would not fit in the space I had to work with so we compromise.
The "center" is just a 1/8" shank from a broken carbide end mill. I always save the broken bits for making
"tools" or cutters at a later date.
I bring down the center into the center hole in the tap and then turn the tap about 1/4 turn and then bring down
the quill again. A small tap handle fits in there very well and once I get 3 or 4 threads I discontinue the use of the center
and just finish tapping in the normal manner.