<p>As pointed out by Jake Palmer on the Klipper forum, I needed to apply <a href="https://www.klipper3d.org/Axis_Twist_Compensation.html" rel="nofollow noreferrer">axis twist compensation</a>.</p>
<blockquote>
<p>Some printers may have a small twist in their X rail which can skew the results of a probe attached to the X carriage. This is common in printers with designs like the Prusa MK3, Sovol SV06 etc...</p>
</blockquote>
<p>I have Z braces installed but I believe these were poorly set and exacerbating the twist. After fiddling a little while I got dramatically better prints.</p>

CC BY-SA 4.0
2024-02-19T19:48:53.543Z
2024-02-19T19:48:53.543Z
rgov
<p>I am using Klipper on a modified Wanhao Duplicator i3 (Monoprice Maker Select V2) featuring a BLTouch probe. I am working through the painstaking process of bed leveling, but even though Klipper seems happy with the level, my first layer calibration print using SuperSlicer is not coming out well:</p>
<p><a href="https://i.sstatic.net/L2POH.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/L2POH.jpg" alt="output of calibration print" /></a></p>
<p>First, I adjusted the gantry to be level to the table (not the bed). I checked that the <code>PROBE_ACCURACY</code> looks good:</p>
<pre><code>probe accuracy results: maximum 1.995000, minimum 1.987500, range 0.007500, average 1.991250, median 1.991250, standard deviation 0.002016
</code></pre>
<p>Then I use the <code>SCREWS_TILT_CALCULATE</code> command to adjust the bed screws until they are very close:</p>
<pre><code>rear left screw : x=50.0, y=200.0, z=1.89750 : adjust CCW 00:02
rear right screw : x=200.0, y=200.0, z=1.89750 : adjust CCW 00:02
front right screw : x=200.0, y=50.0, z=1.89500 : adjust CCW 00:02
front left screw (base) : x=50.0, y=50.0, z=1.87750
</code></pre>
<p>The <code>BED_MESH_CALIBRATE</code> command determines that there is maybe a 0.185mm inconsistency across the bed.</p>
<p><a href="https://i.sstatic.net/eppMU.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/eppMU.png" alt="BED_MESH_CALIBRATE mesh" /></a></p>
<p>I added <code>BED_MESH_PROFILE LOAD=default</code> to my start GCODE, after homing completes.</p>
<p>Then I ran the bed/extrusion test print that SuperSlicer generated for me, shown at the top of the post. The center looks best but the left side is too far and the right side is much too close.</p>
<p>Isn't the mesh supposed to correct for this? What might I still have wrong?</p>

CC BY-SA 4.0
2024-02-18T21:32:29.080Z
Even if my probe's Z offset were wrong, wouldn't the calibration print be consistently bad?
rgov
<bed-leveling><bltouch><monoprice-maker-select><wanhao><superslicer>
Poor first layer even after careful calibration
rgov
# Poor first layer even after careful calibration

(Asked by: username_0 on 2024-02-18)

I am using Klipper on a modified Wanhao Duplicator i3 (Monoprice Maker Select V2) featuring a BLTouch probe. I am working through the painstaking process of bed leveling, but even though Klipper seems happy with the level, my first layer calibration print using SuperSlicer is not coming out well:

[![output of calibration print](https://i.sstatic.net/L2POH.jpg)](https://i.sstatic.net/L2POH.jpg)

First, I adjusted the gantry to be level to the table (not the bed). I checked that the `PROBE_ACCURACY` looks good:

```
probe accuracy results: maximum 1.995000, minimum 1.987500, range 0.007500, average 1.991250, median 1.991250, standard deviation 0.002016

```

Then I use the `SCREWS_TILT_CALCULATE` command to adjust the bed screws until they are very close:

```
rear left screw : x=50.0, y=200.0, z=1.89750 : adjust CCW 00:02
rear right screw : x=200.0, y=200.0, z=1.89750 : adjust CCW 00:02
front right screw : x=200.0, y=50.0, z=1.89500 : adjust CCW 00:02
front left screw (base) : x=50.0, y=50.0, z=1.87750

```

The `BED_MESH_CALIBRATE` command determines that there is maybe a 0.185mm inconsistency across the bed.

[![BED_MESH_CALIBRATE mesh](https://i.sstatic.net/eppMU.png)](https://i.sstatic.net/eppMU.png)

I added `BED_MESH_PROFILE LOAD=default` to my start GCODE, after homing completes.

Then I ran the bed/extrusion test print that SuperSlicer generated for me, shown at the top of the post. The center looks best but the left side is too far and the right side is much too close.

Isn't the mesh supposed to correct for this? What might I still have wrong?

**Tags:** bed-leveling, bltouch, monoprice-maker-select, wanhao, superslicer

> **Comments:**
> **username_0**: Even if my probe's Z offset were wrong, wouldn't the calibration print be consistently bad?  

---

## 1 answers

### Answer by username_0 on 2024-02-19. Score: 1

As pointed out by Jake Palmer on the Klipper forum, I needed to apply [axis twist compensation](https://www.klipper3d.org/Axis_Twist_Compensation.html).

> Some printers may have a small twist in their X rail which can skew the results of a probe attached to the X carriage. This is common in printers with designs like the Prusa MK3, Sovol SV06 etc...

I have Z braces installed but I believe these were poorly set and exacerbating the twist. After fiddling a little while I got dramatically better prints.


---

