# Z-20 (Heavy Duty Z-Slider)

**URL:** <https://forum.onefinitycnc.com/t/z-20-heavy-duty-z-slider/20499>\
**Category:** Uncategorized\
**Created:** [May 8, 2023, 4:06am UTC](https://forum.onefinitycnc.com/t/z-20-heavy-duty-z-slider/20499 "2023-05-08T04:06:26Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![349iq2345](https://avatars.discourse-cdn.com/v4/letter/3/bb73d2/32.png) [@349iq2345](https://forum.onefinitycnc.com/u/349iq2345)\
**Post date:** [May 8, 2023, 10:30am UTC](https://forum.onefinitycnc.com/t/z-20-heavy-duty-z-slider/20499/2 "2023-05-08T10:30:34Z")

</div>

Hey Dan,

> [@Danny72](#):
>
> everything is working great except for the Z axis, When I hit start it plunges down all the way it’s like the motor is losing power. Do I need to change something in the motor settings to correct this problem ?

yes, you need to load the correct configuration:

- [Installing the Z-20 Heavy Duty Z Slider (configuring the software)](https://forum.onefinitycnc.com/t/installing-the-z-20-heavy-duty-z-slider-configuring-the-software/18666).

This applies to firmware [1.2.1](https://github.com/OneFinityCNC/onefinity-firmware/releases/tag/v.1.2.1) and later.

> [@Installing the Z-20 Heavy Duty Z Slider (configuring the software)](https://forum.onefinitycnc.com/t/installing-the-z-20-heavy-duty-z-slider-configuring-the-software/18666/1):
>
> ![55](https://us1.discourse-cdn.com/flex022/uploads/onefinitycnc/original/3X/0/7/074d4ce6b8a0dc77828017e14dcd2e1c93b8b47b.jpeg)

Should you be on firmware [1.0.9](https://github.com/OneFinityCNC/onefinity-firmware/releases/tag/v1.0.9) or earlier, after installing [Z-20 assembly](https://www.onefinitycnc.com/product-page/z-20-heavy-duty-z-slider), you need to set these values of **Motor 3** on its MOTOR page **manually** instead:

- “ **travel-per-rev** ” to “ **10** ”
- “ **min-soft-limit** ” to “ **-160** ”, and
- “ **max-velocity** ” to “ **7** ”

This is what the “Pick your Z Slider Type” choice sets (as shown in the image) above when choosing “Z-20 Heavy Duty”. The Z-20 assembly **will** work correctly if you set it manually this way.

Note that additionally when using a heavier milling motor, you can adjust (increase) the ‘ **drive-current** ’ and ‘ **idle-current** ’ settings the “[Motor → Power](https://buildbotics.com/manual-v1-0/#power)" section of motor 3 on the MOTORs page.

Should also [stall homing](https://forum.onefinitycnc.com/t/how-common-are-missed-steps/18352/8) on Z axis not work correctly, you may also adjust stall homing settings ([see here for details](https://forum.onefinitycnc.com/t/stepper-motor-setting-help/20462/2)).

Welcome to the forum!

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