# Z Height Showing Negative Number for Spoilboard After Calibration **URL:** \ **Category:** General Chat\ **Created:** [March 16, 2025, 8:45pm UTC](https://forum.avidcnc.com/t/z-height-showing-negative-number-for-spoilboard-after-calibration/4517 "2025-03-16T20:45:58Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![DavidMckee](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@DavidMckee](https://forum.avidcnc.com/u/DavidMckee)\ **Post date:** [March 16, 2025, 8:45pm UTC](https://forum.avidcnc.com/t/z-height-showing-negative-number-for-spoilboard-after-calibration/4517/1 "2025-03-16T20:45:58Z")
When I run the Tool Height Calibration and then the Spoil Board Calibration the Z Height for the Spoil Board shows a value of -.04108 when I lower my tool to the same spot as I calibrated the Spoil Board. Also, If I measure my tool and go back to the site it is showing the same -.0410. Why is this not showing Zero instead of being almost 1/2 inch wrong. Zero is .04108 above the Spoil board?? Thanks, David McKee ---
**Author:** ![Eric](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.avidcnc.com/eric/32/3220_2.png) [@Eric](https://forum.avidcnc.com/u/Eric)\ **Post date:** [March 16, 2025, 10:44pm UTC](https://forum.avidcnc.com/t/z-height-showing-negative-number-for-spoilboard-after-calibration/4517/2 "2025-03-16T22:44:29Z")
Go to Set Part Zeros\>WCS Table and look to see what your Z offset is. If it’s not 0 then set it to zero. Then when you put a tool that’s been touched off on the tool height setter on the spoilboard it should read zero in the DRO ---
**Author:** ![DavidMckee](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@DavidMckee](https://forum.avidcnc.com/u/DavidMckee)\ **Post date:** [March 17, 2025, 3:24am UTC](https://forum.avidcnc.com/t/z-height-showing-negative-number-for-spoilboard-after-calibration/4517/3 "2025-03-17T03:24:00Z")
Thanks so much! I will check this later this evening! David