# Issue with delta\_calibrate and z\_offset

**URL:** <https://klipper.discourse.group/t/issue-with-delta-calibrate-and-z-offset/22825>\
**Category:** General Discussion\
**Created:** [April 3, 2025, 8:01pm UTC](https://klipper.discourse.group/t/issue-with-delta-calibrate-and-z-offset/22825 "2025-04-03T20:01:19Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![TpForMyBungholio](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@TpForMyBungholio](https://klipper.discourse.group/u/TpForMyBungholio)\
**Post date:** [April 3, 2025, 8:01pm UTC](https://klipper.discourse.group/t/issue-with-delta-calibrate-and-z-offset/22825/1 "2025-04-03T20:01:19Z")

</div>

### Basic Information:

Printer Model: Custom Delta Printer  
 MCU / Printerboard: BTT Pico  
 Host / SBC: BTT Pi  
 klippy.log

I am setting up a probe and noticed the automatic “delta\_calibrate” command appears to be calculating delta geometry incorrectly, and I think it has something to do with probe, “z\_offset”. delta\_calibrate is calculating arm lengths/ delta radius to be ~3/ 1.5x their actual dimensions.

If it matters, I’ve confirmed my probe is working correctly/ it works just fine when doing things like probe\_calibrate and bed\_mesh\_calibrate.

**Correct known dimensions for my printer**

- End stops at ~407mm (previously calculated using DELTA\_CALIBRATE METHOD=manual)
- Arm length of ~440mm (previously calculated using DELTA\_CALIBRATE METHOD=manual)
- Delta radius of ~232mm (previously calculated using DELTA\_CALIBRATE METHOD=manual)
- Probe z\_offset of ~ 22.5mm (calculated using probe\_calibrate, which gives correct results)

**For quick reference, incorrect results of current delta\_calibrate command**

- stepper\_a: position\_endstop: 402.833554 angle: 212.749820 **arm\_length: 1361.267107**
- stepper\_b: position\_endstop: 411.978615 angle: 333.176185 **arm\_length: 1257.387203**
- stepper\_c: position\_endstop: 405.020518 angle: 90.000000 **arm\_length: 1341.840522**
- **delta\_radius: 411.129110**

[klippy.zip](https://klipper.discourse.group/uploads/short-url/yPTEMFCpnXyXTKWLBwqFok15qbW.zip) (1.2 MB)

---

<div class="post-metadata">

**Author:** ![Mulcmu](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/mulcmu/32/18255_2.png) [@Mulcmu](https://klipper.discourse.group/u/Mulcmu)\
**Post date:** [April 18, 2025, 8:10pm UTC](https://klipper.discourse.group/t/issue-with-delta-calibrate-and-z-offset/22825/2 "2025-04-18T20:10:56Z")

</div>

Your printer.cfg has distances in the [delta\_calibrate] section. It looks to me like detla\_analyze was run at some point so it is using that data and calculating arm lengths. The delta calibrate [docs](https://www.klipper3d.org/Delta_Calibrate.html#additional-notes) have a note that unexpected values may be returned. You could do a bed mesh with that configuration and see how flat that looks but be ready for emergency stop.

I’d delete out all saved configuration by delta calibrate and restart with your known correct values.

---

<div class="post-metadata">

**Author:** ![TpForMyBungholio](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@TpForMyBungholio](https://klipper.discourse.group/u/TpForMyBungholio)\
**Post date:** [April 24, 2025, 5:52am UTC](https://klipper.discourse.group/t/issue-with-delta-calibrate-and-z-offset/22825/3 "2025-04-24T05:52:04Z")

</div>

> [@Mulcmu](#):
>
> I’d delete out all saved configuration by delta calibrate and restart with your known correct values.

Thanks for the suggestion; that did the trick.

---

<div class="post-metadata">

**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/klipper/original/1X/64419bf2aac6639e6ef5cef200dcd456b0a01ac3.png) [@system](https://klipper.discourse.group/u/system)\
**Post date:** [May 24, 2025, 3:52pm UTC](https://klipper.discourse.group/t/issue-with-delta-calibrate-and-z-offset/22825/4 "2025-05-24T15:52:05Z")

</div>

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.