I think this has been posted on these forums before but I thought I'd share my own setup. I do a lot of probing for my software product which essentially means that the tool needs to be grounded. This is my old setup:
The problem with this clip is that: 1. I can and have forgotten to attach the clip meaning there is no continuity between the tool and surface and therefore the tool often breaks and embeds itself in the workpiece and puts a big hole in the surface.
2. I can and have forgotten to remove the clip after probing and before the spindle starts up. This tends to grind away at the colet as it spins at ~8000rpm, plus it makes a horrific noise.
The only part of the spindle which offers continuity to the tool is the nut at the top.
The solution then:
Here I have used an old feeler gauge to act as a spring to contact the nut. A wire is connected to the spring which is then grounded. So, the tool is always grounded now which eliminates the problems.
OK got it. The only thing is, I found your post originally through a google search and it seems difficult to find on the wiki IMO. Maybe this should be a separate article as well on the wiki, posted under the spindle heading. Just a thought.