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Batch B03 — A/B drive units + front idlers

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Read this chapter one step per page — big pictures, prev/next, and the same tick marks. This page is the whole chapter in one scroll.

Revali watching a first layer
The corners the belts turn on. Flange seats again, which means Gate B votes first.

Time: 8.5 h (1 plate) — PrusaSlicer 2.9.6 estimates.

Sessions: 1 plate start (~5 min hands-on, 8.5 h unattended) + ~15 min inspect and bin.

Prerequisites: Gate B passed (Step B00.7 — these are F695 flange seats; the caliper and insert rows run early, on what is already on the bench). B02 is not a print prerequisite: its accent [a]_cable_cover, [a]_z_chain_retainer_bracket and [a]_tensioner_left/right printed one batch earlier, at B02, and are already in 04-A / 04-B.

Printed parts

STL Repo path Qty Colour g ea Bin
a_drive_frame_lower.stl Voron-2 STLs/Gantry/AB_Drive_Units/ 1 Black 22.4 04-A
a_drive_frame_upper.stl Voron-2 STLs/Gantry/AB_Drive_Units/ 1 Black 21.8 04-A
b_drive_frame_lower.stl Voron-2 STLs/Gantry/AB_Drive_Units/ 1 Black 20.5 04-B
b_drive_frame_upper.stl Voron-2 STLs/Gantry/AB_Drive_Units/ 1 Black 21.3 04-B
front_idler_left_lower.stl Voron-2 STLs/Gantry/Front_Idlers/ 1 Black 7.7 04-B
front_idler_left_upper.stl Voron-2 STLs/Gantry/Front_Idlers/ 1 Black 14.1 04-B
front_idler_right_lower.stl Voron-2 STLs/Gantry/Front_Idlers/ 1 Black 13.8 04-A
front_idler_right_upper.stl Voron-2 STLs/Gantry/Front_Idlers/ 1 Black 7.9 04-A

Hardware: none.

Read first

  • Checkpoint after B03: the F695 flange seats caliper 15.00 mm now, and the two halves of each drive unit must close flat with no gap. On kit day the real F695-2RS (13 mm OD, flanged) bearing/spacer stacks must drop into those seats without reaming. (625-2RS is the Z-drive bearing, B01 — not this batch.)
  • Most commonly reprinted here: a/b_drive_frame_lower — the bearing seats are the tightest fit in the machine.
  • A and B share one plate (merged 2026-09-06, one swap instead of two), so a failed plate costs both drive units. Watch the first layer before you walk away from an 8.5 h print.

Step B03.1 — Filament prep

Do: Swap the accent spool for Galaxy Black: Unload, Load Filament → ASA, purge until no blue shows. The ledger has B03 on spool #1 with 447 g, leaving 328 g after. Sheet per 00-slicer-setup § Print sheet.

check Check

Purge clean black, no blue streak.

Source: print plan §4.3 — spool changes · 00-slicer-setup § Drying · Prusa KB — ASA

Step B03.2 — Load plate B03-P1 (both sides)

Sorting diagram, drawn from the committed project: every part numbered and filled in the colour of its bin, bin id on the part; the legend reads # · STL · bin (chapter · steps). Sort at Step B03.5.

Do: Open slicer/plates/B03-P1.3mf with File → Open Project. Arrangement, per-object brims and overrides ship in the project; confirm what loaded, don't rebuild it. No rotation, no brim in the project. Parts: 8 objects — 8.5 h, 119 g (PrusaSlicer 2.9.6 estimate); a_drive_frame_lower; a_drive_frame_upper; front_idler_right_lower; front_idler_right_upper; b_drive_frame_lower; b_drive_frame_upper; front_idler_left_lower; front_idler_left_upper.

check Check

Parts sit flat as shipped; no brim outline in the preview.

Helper: Reads the sorting diagram legend aloud and counts the parts on it while you load.

Source: print plan §3 — the batches · 00-slicer-setup § Committed projects · 00-slicer-setup § Orientation & brim

Step B03.3 — Print plate B03-P1

Do: Print with standing overrides.

check Check

Before start, Settings → Chamber Filtration reads Adv. Filtration. No warp at drive-frame corners.

tip Tip

Paused or stopped mid-plate? See When the printer stops.

pause Good stopping point · ~5 min since the last one

plate started; nothing to do until it finishes.

Source: 00-slicer-setup § Overrides · print plan §4.1 — how these numbers were produced

Step B03.4 — Inspect

Do:

  1. Now: caliper each drive frame half's F695 flange seat, a 15.00 mm pocket 4.00 mm deep.
  2. Now: dry-fit each drive unit's two halves, which must close flat.
  3. Kit day: drop a real F695-2RS in, no rocking.

check Check

Every seat reads 15.00 mm ±0.15 and both halves close with no visible gap.

pause Good stopping point · ~10 min since the last one

seats calipered, halves dry-fitted and separated again. Nothing pressed for keeps; the bearings themselves are a kit-day row.

Source: print plan §5.2 — checkpoint after each batch · 00-slicer-setup § Gate B · LDO Build Notes / FAQ

Step B03.5 — Sort into bins

Do:

  1. Sort the plate off its diagram: number to legend, colour to bin, bin id on the part.
  2. Mark plate id and date on a hidden face.
  3. A is the right-hand side, B the left.

B03-P1

bin parts off this plate
04-A — A drive unit + A (right) front idler a_drive_frame_lower, a_drive_frame_upper, front_idler_right_lower, front_idler_right_upper
04-B — B drive unit + B (left) front idler b_drive_frame_lower, b_drive_frame_upper, front_idler_left_lower, front_idler_left_upper

check Check

04-A and 04-B each hold one drive-frame pair, one idler pair and one blue tensioner.

Helper: Writes the bin id and the date on the inside face of each part.

tip Tip

the blue [a]_tensioner_right and [a]_tensioner_left from B02 are already in these two bins. Print bin labels from the bin-labels sheet.

pause Good stopping point · ~10 min since the last one

both bins sorted and labelled, A-side and B-side parts kept apart. Nothing is pressed or bolted; Ch 04 builds from the bins.

Source: print plan §9 — batch summary · print plan §2 — which parts gate which step · print/README § Bins

Checkpoint B03

  • Gate B passed before B03-P1 started
  • F695 flange seats in a/b_drive_frame_lower/upper caliper 15.00 mm ±0.15
  • (kit day) a real F695-2RS sits in each seat with no rocking
  • Drive unit halves (upper+lower) close flat with no visible gap, both A and B
  • No corner warp on any of the eight parts
  • A-side parts in 04-A, B-side parts in 04-B
Revali passing a gate
Batch B03 printed: plate 7 of 22, 57.2 of 157.0 h. 1 gummy worm.

Common mistakes

  • Mixing A-side and B-side parts in one bag — they are not interchangeable.
  • Force-closing a warped drive-frame half instead of reprinting it.
  • Skipping the dry-fit and only discovering the bearing-seat gap during final assembly.

Next

Assembly: A/B Drives and Idlers (p.62–81). Printing: B04 — XY joints + X carriage.