Z axis

[Gordon]

How do you zero out the Z axis on a mill? Running the cutter down against the work piece seems crude and not too accurate. Is there a better or correct way to do this?

 

[pgp001]

What you said but with the cutter NOT rotating.

Phil

 

[Rivergypsy]

You can get tool setters (http://www.ymtltd.co.uk/height-presetters-and-accessories-/99-hp-50a-height-presetter.html), but to be honest all I normally do is touch a stationary tool to the work. If you're worried, you can always use a thin cigarette paper to sense then it's touching

 

[ausdier]

Some people wet a thin piece of paper and put it on the surface you are going to and when you touch and move the paper you know you are close ?

 

[Gordon]

As unbelievable as it sounds I have actually been doing it the right way. Just sounds too crude to be the correct way.

 

[Rivergypsy]

So are a lot of things, lol

 

[neseng]

Without the cutter spinning, I usually bring the cutter down (or table up) to a feeler gauge of known thickness, placed between the cutter and the work piece. Then move the cutter off to your X0 Y0 start point and lower the cutter (or raise the table) by that known (feeler gauge) amount. Hope this helps, Cheers, Norman.

 

[neilw20]

Touch business card until you can feel it. Set display to the thickness.
The for really accurate, with cutter spinning, and observing with high magnification bring it down until you can see the cut, just.

or
With spindle stopped. This takes longer to type than do. Doing it is under 10 seconds.
For cutters as small as 1mm, on my SX3, which has a quill (couldn't live without it) I just move down near the job with CNC control, then UP a tad to cancel head nod.
Head nod on the SX3, (going up makes it go down a bit on the change of direction due to slide friction) makes the CNC UP step above important.
Bring the quill down until I can feel it touch, and then a little more so the backlash in quill handle is overcome.
This means the return spring on quill handle is not interfering. Now I lock the quill, and zero the DTI (I have a mechanical one), and zero the CNC DRO. (touch screen)
Mover the quill back so DTI reads zero. My DTI has 1 micron steps!!.
I can set to better than 2 microns, on production basis doing this. Then it is back to my wife who operates the cycle start button.

 

[aonemarine]

I either stick a piece of paper under it, or mark the part with marker and lower while rotating the cutter by hand until it just scrubs off the marker...close enough.

 

[chrsbrbnk]

If you put the cutter down against the work with out it spinning and zero at that point when you turn it on it will cut about .003 deeper. so back it off about 3 thou then set zero. magic marker is about .0005 to .0002 thick

 

[neilw20]

chrsbrbnk.
You have you maths backwards.
It will .003 LESS deep. Think about it?

 

[stevehuckss396]

I hold my cutters with collets. When i tighten the collet it will pull the tool off the surface. Then I get my feeler guages and measure the gap between the tool and surface. Then i can make the adjustment within a thou.

 

[Tin Falcon]

Gordon any of the tree methods mentioned work.
tool spinning and touchdown is fine as long as you have material to work with and are taking a couple passes.

touching with the tool stationary is ok on soft material. steel against steel you risk chipping the tool.


the paper method is the best especial if you are taking a final finish cut and only have thousandths to remove. IMHO if in doubt use method 3
have the tool spin and let it grab the paper.
Tin

 

[chrsbrbnk]

no if you set the cutter down against the work cutter not spinning, then set you zero or lock the spindle. it'll take a few thou of your work if you take your cut at that zero. try it. i've had various ideas as to why but it happen on vitually all mills cnc or otherwise

 

[Mike N]

What you said but with the cutter NOT rotating.

Phil

What could be easier than this? It works! :wall: