Best method for zeroing in on the top of part

I use paper also. Just learned this on the net. Use ciggarette roling paper . Measures about 1/2 thou.
 
Maplehead said:
Thanks for the suggestions. I wonder if the following would work: For chucks or collets, what if I leave the drill bits or end mills in them loosely, lower the z-axis until the tool is resting on top of the work piece, tighten my z-axis and then tightened the chuck or collet?
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The jaws on a chuck move out from the body of the chuck. As the jaws start to grab the tool, it will carry the tool slightly as well. A collet with a tapered body will be drawn slightly in as the collet is tightened. It would be OK to use your method for non critical work but I wouldn't expect to set to a thousandth.

A way similar to what you propose that I have used is to use an end mill holder and Weldon type end mills. Snug the set screw to capture the end mill and back it off slightly. Lower the end mill to contact the work and tighten the set screw. This will get you to a thousandth or two.
 
My dad showed me the paper trick. He was a toolmaker as a career so well worth listening to. Maybe a few other topics along the way, also. But it always seemed a little scary to get my fingers close to spinning knives.

I could see Bob’s phone book as safe enough...maybe when finding a vertical surface where you can’t tolerate a gouge.
I will keep that in mind.
 
Sometimes I use chalk. I rub the surface with the chalk and watch it as I progress the cutter. If using paper and while holding, don’t let the paper suck your fingers into the cutter. I know this sounds like it can’t happen, BUT IT CAN!
 
Make a gage 2" x .5" x 1.000 in height . Remove 1 inch of the length off the bottom . You can now bring your tool down to touch off the 1.000 height . If you go too deep , the gage simply rocks . We set many older cncs this way . And yes , don't do the above post......................it's done with spindle off .
 
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Mmcmdl, do you mean something like this:

_
| |
| |
| _ ___|
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|___|

where the mill touches down on the right-hand side of the bottom cut?
NOTE: drawing not to to scale, used for illustrative purposes only :grin:
 
I------------------I
I________I--------I

Something like this . Touch off on top right of gage . ( sorry for my cad drawing ) :rolleyes:
 
Well, my "drawing" looked a lot better when I was composing it. Not sure what happened after that, but, yeah, what "mmcmdl" showed.
 
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