Ch 06Checkpoint

Checkpoint 06b

Checkpoint · Chapter 06 — Z axis (and Chapter 06b — Gantry squaring)

• SET_IDLE_TIMEOUT TIMEOUT=99999 set first (Step 06b.1), machine homed and QGL'd (06b.2) before any belt was plucked or any bolt touched
• Four Z belts measured at 140 Hz over a 150 mm span (Step 06b.3), all four within ±5 Hz — set finally at Ch 14 Step 14.5 (cold, same session as 14.4)
• Only stepper_x and stepper_y were disabled; Z motors held the gantry throughout
• A/B belts were fully slack before any adjustment was made
• At every XY joint only the three joint-to-beam bolts (Steps 05.38–05.39) were loosened; at the A/B drives and front idlers both Z belt-clamp pairs were eased only enough to slide, no Z belt end slipped, and all were retightened at 06b.12
• Both A/B joints checked for rotation against the good/bad reference images
• At all four Z joints, the M5×40 starts by hand with the joint raised — no coaxing
• Four-point gantry-to-frame gap recorded: same-side front/rear within 0.5 mm, left/right within 1 mm
• Machinist square shows no light at both front corners, gantry forward and gantry back
• A/B belts re-tensioned to a provisional 110 Hz over a 150 mm span, matched to each other — final value is Ch 14 Step 14.4
• Four Z joint M5×40 bolts still light — they are tightened hot in Ch 14, not here
• RESTART run at Step 06b.16; idle timeout back to default; next page is Ch 13 Step 13.35

Next: Ch 13 Step 13.35 — re-heat and re-QGL after squaring; then Ch 11 Part B.

You built a square, de-racked gantry on four light Z joints. 1 gummy worm.

Common mistakes

• Doing p.114 before p.115–116. Wrestling a 350 gantry on long zip ties while trying to line up four joints. Fit the lower joints and rest the gantry on rubber rail stoppers instead — LDO note p.114–116.
• Fitting the hall-effect block or a 6×3 magnet because the manual shows it. This kit has none (LDO p.145). If you printed z_joint_upper_hall_effect.stl, you printed the wrong file.
• The block's cutout facing inward. It is the one orientation error on p.112 that the manual calls out, and it is invisible once the belt is on. Fix: check all four before belting.
• Putting the twin-hole upper clip on the Z bearing block. The Z-joint stack takes only the lower clip (p.111). The upper clip sits on top of the front idler or drive, under its M5×16 pair (Ch 05, p.91, p.95).
• Removing the top belt clamp screws at p.117, or loosening the wrong pair. The two M5×16 on top also hold the front idler or drive to the Y extrusion: loosen them until a belt slides under the clip. The M3×30 / M5×30 underneath hold the first belt end; leave them alone.
• Cutting Z belts to 1200 mm and finding it is exactly not enough after the wrap. Cut ~1400 mm — long enough to wrap, and it still leaves ~400 mm of the kit's 6 m spare. Cutting four at 1500 mm consumes the whole reel.
• Torquing the M5×40 Z joint bolts now. They stay light through Part B and get their final tighten hot, in Ch 14 (Voron squaring step 16). Tight joints here will fight every squaring adjustment you make.
• Leaving a Z carriage unrestrained near the top of its rail. It slides off, the balls go on the floor, and the carriage is scrap.

Common mistakes (06b)

• Doing this before Ch 13. Four of the seventeen steps are g-code. Attempting it dry means guessing at "level" with no QGL to check against.
• Plucking the Z belts before the idle timeout is raised and the machine is homed. Klipper's default 600 s timeout releases the Z motors mid-step and the gantry sags onto whatever is under it. Steps 06b.1–06b.2 first, every time.
• Tensioning the A/B belts in Ch 07 — or here — and treating that as final. Step 06b.6 undoes Ch 07's, and Ch 14 Step 14.4 sets the real one with the panels on, cold, immediately before the closed-chamber soak. Both earlier values are working values.
• Overdoing the belt clamps at step 06b.10. The gantry is hanging on the Z belts, and at each A/B drive and front idler both bolt pairs clamp one: the top M5×16 its second end, the bottom M3×30 / M5×30 its first. Ease them just enough to slide; a released end drops that corner. At 06b.9 only the three joint-to-beam bolts move.
• Tightening the Z joints cold, here. The point of the hot lock-in (Ch 14 Step 14.6) is freezing the gantry at full thermal expansion; cold-tightening throws that away and shows up as first-layer inconsistency. They stay light from 06b.13 until Ch 14, and light through the rest of Ch 13.
• Skipping the de-racking step because QGL passed. QGL levels the gantry in Z; it says nothing about whether the X extrusion is square to the Y axes. A racked gantry passes QGL happily and prints skewed parts.
• Believing voronldo.com's tension numbers. 80–100 Hz (A/B) and 110–130 Hz (Z) conflict with the official figures and name no span. Use 110 Hz and 140 Hz over 150 mm (survey §4.3).

Next

After Part A: Ch 07 — A/B belts and tensioning (manual p.124–145) once Checkpoint 06 is clear; tension provisionally, because Part B will release it. After Part B: back to Ch 13 Step 13.35 (re-heat, re-QGL, Z=0, mesh, first cube); then Ch 11 Part B (panels and door); then Ch 14 Steps 14.4–14.6 for final belt tension (cold), then the hot soak and the hot Z-joint tighten.

Source: Voron docs § V2 Gantry Squaring, steps 14–17

Good stopping point · ~60 min since the last one

gantry squared and de-racked cold, A/B belts at a provisional 110 Hz, four Z-joint M5×40 still light, RESTART run. Part B is one session by design: it starts by releasing all A/B tension, so stopping part-way leaves the machine unusable. Do not tighten the Z joints and do not chase the belt numbers — both are Ch 14's (belts cold at 14.4–14.5, joints hot at 14.6).

← PreviousStep 06b.16 — Hand off: RESTART, then back to Ch 13 Step 13.35 — panels (Ch 11 Part B) and Ch 14's final tension and hot lock-in come after

Next →Step 13.35 — Re-heat and re-QGL after squaring