I have not had my probe working long enough to scratch anything. I de burred the tip and considered dipping it in plasti-dip for fragile ot to detailed items, oil the tip before I dip it and the rubber tip should slid back off when I am done. Maybe thin the plasti-dip before I dip to get a thinner coating. I have a spray on coat that goes on real thin as well.
the probe is real simple, reall just a NC switch with 3 contacts held shut with a spring and the probe tip on the swash plate, repalce the steel probe with a Delrin and we should be good. ? just my thoughts.