What I use now is a Starrett P/N 25-511 0.2" travel TDI for Z-height setting
http://i72.photobucket.com/albums/i1...uff/TooNo1.jpg , a Starrett 327A 3/8" edge finder for X & Y or a center finder with Interapid 312B-1V tdi with Daedal positioner
http://i72.photobucket.com/albums/i1...nterFinder.jpg
All of the above have about at least 0.06" over travel protection. I tried some electronic edge finders instead of the old reliable 327A and always went back after destroying the electronic types with no over travel forgiveness. Also it is pretty hard to damage an Interapid TDI. Interapid TDIs are pricey but plenty tough. So I would find it hard to shell out $400 for another probe without knowing in advance what type of over travel protection the probe has.
Don
BTW Talk about unforgiving: I have spent many hours with eyes glued to microscope eyepieces using micropostioners on an air table probing 1um structures. When there are a couple of Cascade Microtech RF microwave probes
RF Microwave Probes :: Cascade Microtech, Inc.: that cost $2K+ each and all one has to do is to sneeze or move your arms to quickly off the air table then $5K is instantly flushed. Its a good thing DARPA had good funding.