# Odd Z axis problem

**URL:** <https://forum.onefinitycnc.com/t/odd-z-axis-problem/27010>\
**Category:** Elite Series (Masso & Redline) (Gen 1)\
**Created:** [May 14, 2024, 4:29am UTC](https://forum.onefinitycnc.com/t/odd-z-axis-problem/27010 "2024-05-14T04:29:48Z")\
**Posts on this page:** 1\
**Showing post:** 7

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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 14, 2024, 1:47pm UTC](https://forum.onefinitycnc.com/t/odd-z-axis-problem/27010/7 "2024-05-14T13:47:56Z")

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Hey Tom, hey @cvcolomb,

> [@TMToronto](#):
>
> You are running at 5000 RPM, which in my opinion is very low, even for spindles that claim to be able to machine at those speeds. I believe you will have very little torque.

This is true. On my spindle, a 2.2 kW 6000–24000 rpm spindle, the manufacturer tells in the manual to program a lower speed limit of 6000 rpm in the VFD. The constant torque range of a typical 24000 rpm spindle begins only at 6000 rpm:

> [@Incorrect or missing data on cheap chinese VFDs and spindles](https://forum.onefinitycnc.com/t/incorrect-or-missing-data-on-cheap-chinese-vfds-and-spindles/18909/27):
>
> ![Mechatron_Motor_characteristic_HFS-8022-24-ER20__with_added_comment_Constant_Torque_var4_50pct432x357](https://us1.discourse-cdn.com/flex022/uploads/onefinitycnc/original/3X/f/0/f02061adaa6f8005d23efd7820679edc7ebb5e03.png)  
> – Source: [Mechatron HFS-8022-24-ER20 Datasheet](https://www.mechatron-gmbh.de/fileadmin/user_upload/Datenblatt_HFS-8022-24-ER20.pdf) (with comments added by Aiph5u)

Also when milling wood, you mill at high speeds. This is because the problem with wood is heat. In this popular jazz bass video, everything is milled at 24,000 rpm: [DIY High-End Jazz-Bass-Guitar produced with the CNC machine – Youtube](https://www.youtube.com/watch?v=UMj9k3JTZHo&t=182s). Of course with a large bit diameter you would choose a lower speed, but you’d have to stay inside the constant torque range of your spindle.

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