CNC Touch Probe

thingiverse

I started following Andy Pugh's touch probe build: https://www.youtube.com/watch?v=2ia1_NKQJKs https://www.youtube.com/watch?v=yOvBcecJ3Fg His build features a simple two non-conductive piece design using angled pins instead of balls to form the kinematic mount. I modified his design with an adjustable center and I used a pcb resting on the dowel pins instead of directly soldering to the pins. I had some 5mm pins available so I modified his design to work with these. I turned the center piece from delrin on the lathe. I added a groove and four screws to the center hub for adjusting the center. This adjustment works by flexing the delrin. Be very careful if you use this adjustment mechanism with a 3d print. I often 3d print designs to help me visualize the setups so I printed the probe outer hub to serve as a drilling setup guide. The print turned out so nice, I ended up using the print directly and it seems to work pretty darn well. (I quickly dialed it in to a few tenths of runout) Andy solders directly to the dowel pins. I decided to mill a pcb board and then soldered some solder wick to the board to maintain contact with the dowel pins (which I had roughly cutoff with a dremel). Ordering the correct length pins or using shorter pins with springs would also work. The photos show a temporary stylus created by glueing a bearing to a 4mm screw. I am waiting on some 3mm bearings and 2mm shafts for the stylus. I plan to follow JohnGrimsmo's video: https://www.youtube.com/watch?v=59q8fZ9GV8E A better touchoff tool has been on my project list for quite a while. I finished this project in a couple of days and wish I had tackled it earlier. Thanks to Andy and John for their excellent videos which showed me the way.