[Darth Yoda]

Hi guys.
I need a bit of help on setting tool heights on a Fanuc Oi-MC mill.Yesterday I ran some parts and broke a tool. Put a new tool in and measured it by touching top of part, pressing offset hard key then soft key, scrolling to tool 5 entered Z and pressed INP C. When I started the program again it was a bit higher than 1" off the part. I reset it with no change.

Today I started the machine, jogged it to a random position, then homed it. It reported x-2.9365 y 6.1985 and z 14.1284 in actual (Absolute) system. I checked MDI mode and G54 was active. On this machine its not listed on the position screen.

I started completely over with the tool set up using this method:

Setting up “Z”
1.Touch off the empty spindle against the part using a shim (I suggest a .001 thick shim or feeler gage).
2.Press Offset (hardkey).
3.Press Work (softkey).
4.Scroll down with the cursor arrows until the “Z” field in G54 is highlighted. Be careful as there are two G54 tables. Be sure to use the correct one.
5.Type in “Z” and a the thickness of your shim. Such as this Z.001.
6.Press Measure (softkey) and a value should appear in the “Z” field.............The z at home was 14.1284 and changed to -18.8630.
7.Press Position (hardkey) and the ABS (softkey) to check if “Z” reads zero.

Setting Up the Spindle Nose Reference
1.Stack 1-2-3 blocks to form a “height gage”.
2.Lower the spindle down to the top of the stack with a shim on top. When the shim has enough pressure to cause a slight drag, press Position (hardkey).
3. Press Relative (softkey).
4. Enter Z0.0 and press Preset (softkey)..........it was -5.8366 and changed to 0.0.

Setting the Tool Height
1.Load tool into spindle.
2.Touch off tool to top of stack using a shim or feeler gage.
3.Press Offset (hardkey).
4. Press Offset (softkey).
5.Use cursor arrow keys to highlight the proper tool. Note the offset number.
6.Enter Z and the shim thickness. Such as this Z.001 and press Inp.C.
7.Check to see if offset number has changed..........I used tool 5 and it changed from 9.426 to 5.8390.
Repeat for all remaining tools.


It still comes to 1" off the part. Where am I failing?

[RuckinFugger15]

You're using the 1" side of the 1-2-3 blocks? I used to run an old Johnford mill and had to do the same thing (pressing Z then INP.C.) but what I would do is use your feeler gage to touch the tool off the block and press "Z" with nothing else and then hit INP.C. next type in your feeler/stack height and press INPUT. don't really know if that will work for your machine but who knows.

Also the stack height would be a negative value so jog your Z down to the feeler and press Z then INP.C. next type your -1.001 or whatever it is then hit INPUT.

[Darth Yoda]

I am actually using 6" height of the 123 blocks.

I had an epiphany this weekend. My vice is very high. About 8 inches. This results in the empty spindle being below part ZERO. That might cause a problem due to positive and negative numbers being calculated. I plan on changing vices today to see what happens.

Thanks for the reply tho!!!!

[RuckinFugger15]

let me know how it goes!

[Darth Yoda]

Looks like the machine was on or very close to the Z soft limit but wasn't throwing an error.

Changed my style of doing things and it seems to be working.


I started completely over with the tool set up using this method:
After setting X and Y.......

Setting up “Z”
1.Touch off the empty spindle against the part using a shim (I suggest a .001 thick shim or feeler gage).
2.Press Offset (hardkey).
3.Press Work (softkey).
4.Scroll down with the cursor arrows until the “Z” field in G54 is highlighted. Be careful as there are two G54 tables. Be sure to use the correct one.
5.Type in “Z” and a the thickness of your shim. Such as this Z.001.
6.Press Measure (softkey) and a value should appear in the “Z” field.............The z at home was 14.1284 and changed to -18.8630.


Setting Up the Spindle Nose Reference
1.Stack 1-2-3 blocks to form a “height gage”. Skipped this.
2.Lower the spindle down to the top of the PART with a shim on top. When the shim has enough pressure to cause a slight drag, press Position (hardkey).
3. Press Relative (softkey).
4. Enter Z0.0 and press Preset (softkey)
Added this part..........Jog tool to XY zero.
On relative screen, press OPRT and then ORIGIN and ALLEXE. THis makes your read out read correctly to the (G54) origin you set up.


Setting the Tool Height
1.Load tool into spindle.
2.Touch off tool to top of PART using a shim or feeler gage.
3.Press Offset (hardkey).
4. Press Offset (softkey).
5.Use cursor arrow keys to highlight the proper tool. Note the offset number.
6.Enter Z and the shim thickness. Such as this Z.001 and press Inp.C.
7.Check to see if offset number has changed..........I used tool 5 and it changed from 9.426 to 5.8390.
Repeat for all remaining tools.

This has worked on a couple different set ups today.
Thanks for the suggestions and have a great day!!!