hi

I'm having problems with the z accuracy on my router - its a basic 6040 chinese model but has been pretty useful so far.  Im running mach3 under xp and am using a usb interface

so I zero off the bit on the workpiece and then hit either ref all zero or zero x y and z manually ...

i then jog it up so I can snap my dust hood on -

I then press the goto zero button in mach 3 expecting the bit to go reliably back to the surface position

sometimes this works but sometimes the bit plunges a few mm into the part - eek ..

any idea what might be happening?

regards

keith

Hi Keith,

Don't hit the Ref All Zero button - just zero the X, Y, Z manually - this should resolve your immediate problem.

Tweakie.

thanks tweakle

so i just tried what you said - first and second time it returned to exactly the right spot after the arbitrary z jog, the next time i jogged up and hit the goto zero it plunged about a 8 mm into the stock.  at finish of the move the readout in mach still said z = 0

it then occurred to me that when jogging up that 3rd time i was hitting the limit of travel of the z -  and it must therefore be losing steps at that time - this does seems to be the cause of the sometimes error -- sounds right to you ?

cheers  keith

Sounds right to me 

Tweakie.

You can also setup "Soft limits" so it will not hit the hard-stops, given that the steppers not loose steps :-)

good calll - many thanks1