# Loss of Z-zero setting during multiple pass operations

**URL:** <https://forum.sienci.com/t/loss-of-z-zero-setting-during-multiple-pass-operations/4157>\
**Category:** ❓ Something's Up\
**Created:** [November 12, 2021, 10:35pm UTC](https://forum.sienci.com/t/loss-of-z-zero-setting-during-multiple-pass-operations/4157 "2021-11-12T22:35:40Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![MajorSciGuy](https://forum.sienci.com/letter_avatar_proxy/v4/letter/m/f6c823/32.png) [@MajorSciGuy](https://forum.sienci.com/u/MajorSciGuy)\
**Post date:** [November 12, 2021, 10:35pm UTC](https://forum.sienci.com/t/loss-of-z-zero-setting-during-multiple-pass-operations/4157/1 "2021-11-12T22:35:40Z")

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I am using Fusion 360 and gSender with my LongMill.

I am trying to cut through a 1/4 inch board using multiple passes but the machine is losing its Z-zero setting between passes. The first pass is good, but the second pass of the same operation comes up shallow and the cut does not go through the stock.

After the operation ends I send the machine back to Z-zero it now sits 1/8" above the stock top.

Any ideas or suggestions?

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**Author:** ![gwilki](https://forum.sienci.com/user_avatar/forum.sienci.com/gwilki/32/366_2.png) [@gwilki](https://forum.sienci.com/u/gwilki)\
**Post date:** [November 13, 2021, 3:00am UTC](https://forum.sienci.com/t/loss-of-z-zero-setting-during-multiple-pass-operations/4157/2 "2021-11-13T03:00:32Z")

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@MajorSciGuy Welcome to the group, Jeffrey. You could write books about what I don’t know about Fusion 360, so I don’t know how much I can help. However, if you post your gcode, I can take a look. With luck, others here using Fusion may have ideas,too.

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**Author:** ![Iguana](https://forum.sienci.com/letter_avatar_proxy/v4/letter/i/e0b2c6/32.png) [@Iguana](https://forum.sienci.com/u/Iguana)\
**Post date:** [November 13, 2021, 6:44am UTC](https://forum.sienci.com/t/loss-of-z-zero-setting-during-multiple-pass-operations/4157/3 "2021-11-13T06:44:10Z")

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Any chance the Z axis is bottoming out? If you’ve got the router mounted too high in the bracket, it is possible it may not physically be able to move down far enough to go through the stock.

DAMHIKT…

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**Author:** ![MajorSciGuy](https://forum.sienci.com/letter_avatar_proxy/v4/letter/m/f6c823/32.png) [@MajorSciGuy](https://forum.sienci.com/u/MajorSciGuy)\
**Post date:** [November 13, 2021, 1:07pm UTC](https://forum.sienci.com/t/loss-of-z-zero-setting-during-multiple-pass-operations/4157/4 "2021-11-13T13:07:24Z")

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Thanks for the help. The Z axis was bottoming out. Another thing to keep an eye on while I travel up the learning curve. Cheers.