Why does bit touch plate solution work?

[Coleywood]

I was having a problem in that the carving bit would stop about 1/4" shy of the touch plate and then about the same distance shy of the work surface. I read in a thread that gently pushing down on the flex shaft, and consequently the Z truck, would get the machine to work, and it did. My question is, how does this "solution" work? What am I doing with this sort of hokey fix that perhaps I should find a better permanent fix?

[dbfletcher]

I'm not sure I really like that "solution". When the z-truck goes down to find the bit plate.... the software is monitoring the current of the z-motor. When the motor encounters resistance (ie.. the bit plate), the current goes up and the software recognises that it hit something.... Your fix works by allowing the z-truck to get past whatever is causing the resistance on the way down to the bitplate (or surface of the board depending on what action you are looking at). In essence, you are "masking" the underlying problem. You need to determine what is causing the resistance to movement before the truck is getting to where it actually should be hitting resistance. I hope my rambling was at least a little clear... but wanted to reply before I was heading for home this evening.

I'm sure others will also post with hopefully better explainations.

[CarverJerry]

I would make sure the Z truck moves freely up & down. No chips in the belt and cog and that the rails are clean.

CJ