A timely thread for me. I acquired a used milling table for my SL earlier this year. So far I've only used it for drilling but in the past week have been making some extra 'T' nuts so I thought it would be nice to mill the flats on the SL.
For this job I gave up trying to use any 'Z' feed - I just set the 'Z' to the right place once and then locked the quill with the two clamping screws. I then used the side of the cutter, probably stepping over (on the cross slide) by maybe 0.05mm per cut and listening to the noise to decide whether I was asking for too much. For this particular job it had the advantage of repeatability - all of the new nuts were cut to the same 'Z' depth. I had the job mounted on some M6 studding with a normal nut locked tight against it - the flats on the nut in the vice jaws then kept the two cuts parallel.
I'd agree that it would be unwise to ask too much of the DB/SL in milling mode. I always find milling rather stressful - I regard the cutter as actively trying to damage itself, the job, the machine and me. Make sure everything is clamped up tight and then go round and check it all again. Re-check at intervals because the vibration can loosen things too.
I also found that climb milling seemed to reduce the volume of the noise so ended up taking all of my cuts in that direction. This seems to be contrary to the usual advice for small machines but that was my experience.
