Step 06b.3 — Set the Z belts to 140 Hz¶
Step 29 of 42 with a helper · Chapter 06 — Z axis (and Chapter 06b — Gantry squaring)
(no image — see text)
Parts: none.
Do:
- Jog until a top belt clip sits 150 mm below its Z idler centre.
- Pluck that span; adjust the tensioner until the lowest peak reads ≈140 Hz.
- Re-check all four after a move, then
QUAD_GANTRY_LEVEL.
Check
All four Z belts read 140 Hz ±5 Hz, and they still do after the gantry has moved and come back; QGL converges again afterwards.
Helper Holds the phone at the belt span and reads the lowest peak aloud after each pluck.
What you're looking at
Plucking a measured 150 mm span and reading the lowest peak in a spectrum app turns belt tension into a number; 140 Hz is Voron's figure for the 9 mm Z belt. Four Z belts at four tensions make QGL wander.
Added step, not in the official squaring procedure: do it only after the idle timeout is raised and the machine is homed, so the Z motors hold the gantry throughout. Measure the span from the idler axle down to the clip. The tensioner head sits under the blue slider and takes a 2.5 mm key from below; clockwise as you look up at the head is tighter (verify on bench — the note rises). Voron's "fixed side" is this end of the belt, the one fixed at the joint (verify on bench). Uneven Z belts are a named cause of a high-σ, non-repeatable QGL, and squaring with mismatched Z belts wastes the session (survey §4.3). This is the working setting QGL squares from; Ch 14 Step 14.5 sets it for the last time, cold, before the closed-chamber soak. src
Source: Voron docs § V2 Gantry Squaring, step 1 (prerequisite) · Voron docs § Secondary printer tuning — A/B and Z belts · Ellis' Print Tuning Guide § V2 gantry squaring