Manual Bed Tramming¶
Before running an Automatic Bed Mesh—especially when using high-speed eddy current sensors like the BTT Eddy, Cartographer, or Beacon—it is critical to ensure the bed is physically "trammed" (leveled).
If the bed is severely tilted, the sensor or nozzle may collide with the build plate during the scanning process, potentially damaging your hardware.
The Manual Tilt Test¶
This test confirms that your bed is level enough to safely allow the printer to take over.
1. Prepare the Machine¶
- Home the printer: Run a
G28command. - Position the Nozzle: Move the toolhead to the Front-Left corner.
- Set Reference Height: Lower the Z-axis until the nozzle is roughly 1mm (or about the thickness of a credit card) above the bed.
2. The "Slide & Glide" Check¶
- Unlock Motors: Send the command
M84to disable the motors. - Manual Move: Gently and slowly slide the toolhead by hand to each of the four corners of the bed.
3. Evaluate the Results¶
| Observation | Meaning | Required Action |
|---|---|---|
| Uniform Gap | The nozzle stays ~1mm away from the bed in all corners. | Safe. You are ready to run your Bed Mesh. ✅ |
| Widening Gap | The nozzle gets much higher as you move. | Adjustment Needed. The bed is too low in those areas. |
| Contact/Collision | The nozzle touches or scrapes the bed before reaching a corner. | CRITICAL. Do NOT run a bed mesh. You must manually level the bed first. ❌ |
Why This Matters¶
Eddy current sensors are fixed-mount. Unlike a BL-Touch, they do not retract. If your bed is tilted by several millimetres:
- The "low" side of the bed might calibrate correctly.
- As the printer moves to the "high" side, the slope of the bed may rise faster than the printer expects.
- The sensor housing or the nozzle may crash into the bed at high speed.
If you cannot move the nozzle to all four corners manually without hitting the bed, refer to How can I make sure my bed is level / trammed?