The drill press, Central Machine, (same as several others sold under different names), doesn't have any way to lock the spindle in place.  Plus, it chattered fearfully when lowered.
So I tried it by cutting a piece of aluminum held in an x-y vise with the spindle fully raised.  It cut pretty well, going slowly it didn't chatter.
So, I came up with a set-up where I raise and lower the vise so that each end mill is at the appropriate depth with the spindle fully raised.  Then I remove the cutter, place the lower in the vise. insert the cutter and double check with the calipers before FINALLY cutting!
Man does this take time and patience, but, unless I get a different drill press, this is the best method I can think of.
In the photo, there are several blocks of wood, they are each 1/4" different and for a stubby 3/8" Hogging cutter that I use first, to save time!, I stack the blocks.  I just have to watch how tight I go on the 4 5" bolts that clamp the vise to the bench.  I have wing-nuts on the bottom.
I also swing the regular adjustable table to the rear when using the vise, then, for drilling, I remove the vise and swing the drill press table around from back to front and drill normally, using the stop on the spindle for depth.
It took quite a while to devise this system, but except for the time required to move the vise whenever I have to change cutters, it works and doesn't chatter so bad that I fear for life and limb!
'just another challenge, another puzzle to solve!

Here's the link or image:
https://image.ibb.co/ezZcbQ/20170407_171034.jpg