Step 06b.14 — De-rack the gantry, then tighten the X/Y joints¶
Step 40 of 42 · Chapter 06 — Z axis (and Chapter 06b — Gantry squaring)
Parts: none.
Do: A/B motors disabled, belts still slack: push the X extrusion fully back against both drives until both joints bottom out. Hold it there and tighten the three joint-to-beam bolts at each joint, cross pattern, a bit at a time.
Check
Pushed fully back, both X/Y joints contact their drives at the same instant; the square shows square at both front corners, forward and back.
What you're looking at
Racking is the gantry sitting as a parallelogram instead of a rectangle: QGL passes happily on a racked gantry and the parts come out skewed. Pushing the X extrusion hard against both drive units squares it against the only reference the machine has.
If one side still leads
Loosen the X/Y joint bolts and repeat — the extrusion crept while they came up. If racking persists after two attempts, the community fallback is to loosen each A/B belt's anchor at the X carriage until the belt slides through under a firm pull, pull both belts to equal tension with pliers while feeling the tooth engagement, then re-anchor. Described in the Voron forum's de-racking thread. Re-measure the four points from 06b.11 afterwards and confirm the same-side pair still agrees within 0.5 mm.
Only those six bolts; the drives, idlers and Z belt clamps stay as 06b.12 left them. The Voron doc delegates the method to Nero3D's de-racking video rather than writing it out; this is that method in words.
Voron's own note on this step: "Make sure to come back here afterwards! The following steps are still important."
Source: Voron docs § V2 Gantry Squaring, step 12 · Nero3D — de-racking video · Voron forum — de-racking thread · CAD: Voron 2.4r2 STEP @ de7e89d