Sorry to dig up an old thread here, but whats the progress here?

I am doing some research around safety with CNC machines, and this interests me because it seems it would have the capability to detect when it has hit a foreign object, potentially allowing it to stop if it hits an errant hand before crushing it. Obviously this will only work for machines which have a fairly predictable load/friction, but considering most fingers can withstand 500N briefly before suffering permanent damage, and most CNC machines don't use anywhere near that much feed force, we might be able to design a machine which won't cut your fingers off accidentally.