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Chapter 05 — Gantry: X and Y axes, XY joints, X carriage, titanium backers

One page per step

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.

Builds the complete gantry on the bench — XY bridge, both Y axes with their MGN9 rails, both XY joints, the X extrusion with its MGN12 rail, and the titanium extrusion backers — and ends with the X axis riding on the Y carriages. Unlocks Ch 06 (gantry install, Z belts, squaring).

What you're building in this chapter. The gantry is the entire moving upper half of the printer — a rectangle of aluminium extrusion that later hangs on four belts and slides up and down, with the toolhead riding inside it. Its back edge is the XY bridge, the cross-beam that carries the A and B motors you built in Ch 04. Two side extrusions, the Y axes, run forward from that bridge; each has a linear rail along one face and a front idler block at its front end that turns its belt back. Spanning the two sides is the X beam, capped at each end by an XY joint — the printed blocks that ride on the Y carriages and turn each belt around from its Y run to its X run. Bolted to the face opposite every rail are the titanium backers, flat strips that stop a steel rail bowing its aluminium extrusion as the chamber heats. Nothing in this chapter gets belts or squaring: both belong to Ch 06/07, and both would undo work done here.

Revali turning a hex key
Build the gantry on the bench, not in the frame. Clear the whole table, including that pile.

Time: 5.0–7.0 h hands-on, first build, two people (survey §5.1 P05 / §7.2).

Sessions: 12 × ~30 min (first-build estimate; each Pause: line carries its own segment minutes).

Prerequisites:

  • Ch 04 — A drive, B drive and both front idler assemblies built and checked (manual p.62–81). This chapter consumes them whole.
  • Ch 00 — all seven rails cleaned and packed with grease before they go on an extrusion (LDO rail grease guide); jigs Tools/MGN9_rail_guide_x2.stl and Tools/MGN12_rail_guide_x2.stl printed (batch B00). The rails still wear their Ch 00 end bands (Step 00.17) — they come off at Steps 05.11 / 05.33.
  • Print batches: B04 (XY joints + X carriage, plate B04-P1, 8.6 h, black) and B02-P3 (the blue accent plate — cable bridge, endstop pod and the four upper Z-belt clips) (print plan §B04). B04 needs Gate B (Step B00.7).
  • Titanium backer set (Fabreeko/LDO, 350 size) unpacked and counted, plus 58 M3 roll-in T-nuts counted out from the kit bag: 29 for the rails and extrusion ends, 29 for the backers. The backer set ships none.
  • Ch 01's bagged C ×2, D ×1, E ×1 extrusions.

Tools

  • Hex drivers 2 / 2.5 / 3 / 4 mm; a ball-end 2.5 mm helps at the XY joints
  • T10 Torx driver — strongly preferred for the backer M3 FHCS; hex cams out of a countersink easily (backers README)
  • Printed rail-centring jigs MGN9_rail_guide_x2, MGN12_rail_guide_x2
  • Steel rule 300 mm and a caliper — to equalise the rail overhang at both ends
  • Masking tape (carriage retention) and the kit's rubber rail stoppers
  • 2.5 mm flat screwdriver (cable-chain latches, if you dry-fit the chain end)

Printed parts

Parts arrive in the bins named below (see the bin map in print/README.md#bins); check the bin label's list before you start.

Looks like STL Bin Qty Colour
xy_joint_left_lower_MGN12.stl 05-XY 1 Black
xy_joint_left_upper_MGN12.stl 05-XY 1 Black
xy_joint_right_lower_MGN12.stl 05-XY 1 Black
xy_joint_right_upper_MGN12.stl 05-XY 1 Black
[a]_xy_joint_cable_bridge_2hole.stl 05-XY 1 Blue
XY_cable_chain_bridge-Igus-3mm_backer.stl 05-XY 1 (alternate — fit whichever clears the backer) Blue
x_frame_V2TR_MGN12_left.stl 07-X 1 Black — staged here, fitted in Ch 07
x_frame_V2TR_MGN12_right.stl 07-X 1 Black — staged here, fitted in Ch 07
probe_retainer_bracket.stl 07-X 1 Black — staged here, fitted in Ch 07/08
[a]_endstop_pod_D2F_switch.stl 05-XY 1 Blue — staged here, fitted at endstop wiring
[a]_z_belt_clip_upper_x4.stl 05-XY 4 Blue — fitted here under the idler and drive M5×16 (p.91, p.93, p.95), loaded with belt in Ch 06

Do not print [a]_endstop_pod_hall_effect.stl, [a]_xy_joint_cable_bridge_3hole.stl, or any xy_joint_*_MGN9 — wrong variants for this kit (print plan §7).

Hardware (chapter totals)

Fastener / part Qty Where
E extrusion (XY bridge) 1 p.85
C extrusion (Y axis) 2 p.88
D extrusion (X axis) 1 p.101
MGN9H 400 mm rail 2 Y axes, p.88; carriage ships on the rail
MGN12H 400 mm rail 1 X axis, p.101; carriage ships on the rail
M5 roll-in T-nut 26 8 in E (p.85), 12 in the C pair (p.89, p.90), 6 in D (p.102)
M3 roll-in T-nut 29: 18 Y rails, 4 C-pair ends, 7 X rail 9 per 20-hole MGN9 (p.88), 4 in the C pair (p.90), 7 for the 16-hole MGN12 (p.101)
M3 roll-in T-nut, backers 29: 10 per Y backer, 9 on the X backer from the kit's M3 roll-in bag; the backer set ships no T-nuts
M5×10 BHCS 10 8 bridge-to-drive (p.86–87), 2 left XY joint (p.104)
M5×16 BHCS 10 4 front idlers, through the upper Z-belt clips (p.91, p.93), 4 rear drive joints, same (p.95), 2 right XY joint + cable bridge (p.104)
M5×30 BHCS 2 XY joints from below (p.104)
M5×40 SHCS 8 4 per XY joint (p.97–100)
M3×8 SHCS 25: 18 Y rails, 7 X rail one per marked rail hole (p.88, p.101): every other hole from the second, both end holes empty
M3×16 SHCS 6 XY joints to the Y carriages (p.106): 4 left joint, 2 right joint; all six fitted, none spare
M3×30 SHCS 2: bagged with the endstop pod at 05.46, fitted at 09.33 p.164 fits the pod through its body with 2× M3×30, not the M3×16 of p.106
M5 nut 6 3 per XY joint (p.96)
M5 precision spacer, brass 4 2 per XY joint stack — one below and one above the F695 pair (p.97, p.99) — replaces the manual's "M5 shim"
M5 washer, black 2 under the M5×30 heads (p.104) — replaces the manual's "M5 shim"
F695 bearing 4 2 per XY joint
GT2 20-tooth idler 2 1 per XY joint
Titanium backer, Y — from Ti backer set 2 one per C extrusion
Titanium backer, X — from Ti backer set 1 D extrusion, rear face
M3×8 FHCS, Y backers — from Ti backer set 20: 10 per Y backer tanaes Y_backer-350 DXF: 10 holes (verify on bench)
M3×6 FHCS, X backer — from Ti backer set 9 tanaes X_backer_chain-350 DXF: 9 holes, plus 4 chain pilots (verify on bench)

The West3D/Fabreeko titanium set ships 22× M3×8 FHCS and 10× M3×6 FHCS, two and one spare over the 20 + 9 holes, and no T-nuts (West3D).

Read first

  • The titanium backers go on during this chapter, not after it. Fitting them once the gantry is assembled or installed means a teardown (survey §5.2 W2). They mount on the face opposite the rail — top of the Y extrusions, rear of the X extrusion. "If you have a single MGN12 but decide to put a backer on top, you will be actively contributing to the problem of bimetallic expansion!" src
  • Do not tension the A/B belts and do not square the gantry here. Both are Ch 06/07, and the official squaring procedure begins by releasing A/B tension — tension it now and you undo it (survey §4.4 #2, §5.2 W1). Several joints in this chapter are deliberately left "slightly loose".
  • Every T-nut this chapter needs must go in before the drive and idler frames cap the extrusion ends. LDO: "Due to the tight tolerances of the extrusions and roll-in t-nuts it is advisable to either test fit before assembly … or to pre-load the t-nuts into the extrusions." src
  • Short a part? This chapter needs exact counts: 4 F695, 4 spacers, 2 20T idlers, the backer screws. Recount against your Ch 00 inventory sheet, then contact Fabreeko support; do not borrow from another chapter's bag.
  • Rails ship dry. If Ch 00's clean-and-pack pass has not been done, stop and do it — the flip-and-pack method needs access to the back of the rail (survey §4.4 #5).
  • Carriages slide off rails and are ruined by a drop (manual p.88, p.101). Tape or stopper every carriage the moment its rail is on an extrusion.
  • Orientation. Through p.105 the gantry is built the way it runs — motors hanging down below the bridge, Y rails underneath (p.85, p.116). p.106 turns it upside down (motors up, rails up) so the X axis can be lowered onto the Y carriages; it stays that way to the end of this chapter and is turned back in Ch 06 (Step 06.11). Every step that turns it over says so.

Sources for this chapter:

Video coverage (Steve Builds, pre-release LDO kit — differs from Rev D+): Part 3 @0:56:34 (+2m), Part 3 @1:19:23 (+16m), Part 3 @1:34:36 (+9m), Part 3 @1:43:29 (+5m), Part 4 @0:06:16 (+7m), Part 4 @0:34:10 (+9m), Part 5 @1:05:40 (+1m), Part 5 @1:20:27 (+13m)

Step 05.1 — Clear the bench and confirm the sub-assemblies

What you're looking at: The gantry is the moving frame above the bed that carries the toolhead: a rectangle of extrusions whose X beam slides along two side rails. The page shows it finished, so you can see where the four Ch 04 sub-assemblies land at the corners.

Parts:

  • reused: A drive assembly
  • reused: B drive assembly
  • reused: A idler assembly, front right
  • reused: B idler assembly, front left
  • staged: C extrusion ×2
  • staged: D extrusion ×1
  • staged: E extrusion ×1

Do: Clear a bench at least 700 × 700 mm. Lay the four Ch 04 sub-assemblies out, drives at the top, idlers at the bottom. Keep the A drive on the right and the B drive on the left.

check Check

Four Ch 04 assemblies, each matching its CHECK YOUR WORK page: p.68 and p.72 idlers, p.76 and p.80 drives. All four spin freely.

Source: Voron manual p.82 · Video: Part 4 @0:06:30

Step 05.2 — Name the gantry parts

What you're looking at: The same rectangle, now labelled. A and B are the two CoreXY motors; neither one "is" an axis. The XY bridge holds the drives apart, the XY joints cap the ends of the X beam, and the front idlers turn each belt back.

Parts: none.

Do: Learn the names: B Drive rear left, A Drive rear right, XY Bridge, both XY Joints, X Linear Rail, B Idler front left, A Idler front right. Check the Ch 04 A and B labels.

check Check

You can point at the A drive, the B idler and the right XY joint without hesitating.

Helper: Points to each gantry part as you name it and repeats the name back.

Source: Voron manual p.83

Step 05.3 — Pick the cable-chain bridge

What you're looking at: The cable bridge is the blue arch on top of the right XY joint, lifting the toolhead's drag chain clear of the belts. The two versions differ in the end-link hole pattern: three for generic chains, two for the IGUS chains this kit ships.

Parts:

  • [a]_xy_joint_cable_bridge_2hole.stl ×1 (blue)

Do: You printed the 2-hole bridge and its raised alternate on plate B02-P3, and no 3-hole part. Confirm the bridge has two holes on the raised pad. Set it beside the raised alternate.

Caution

Rev D+ / LDO: "Our cable chain ends use the 2 hole configuration. When printing parts that interface with cable chains, always use the 2hole version instead of 3hole (e.g. xy_joint_cable_bridge_2hole instead of xy_joint_cable_bridge_3hole)." src

tip Tip

keep XY_cable_chain_bridge-Igus-3mm_backer.stl beside it — same 2-hole pattern, raised ~3 mm for a backer. The backers' chain-end holes are pilot only: drill 2.5 mm, tap M3. src

check Check

One 2-hole bridge on the bench, one raised alternate beside it; no 3-hole part exists in this build.

Source: Voron manual p.84 · LDO printed-parts guide (Rev D) · Ti extrusion-backers README (tanaes) · Video: Part 3 @1:43:24

Step 05.4 — Test-fit T-nuts and stage the fasteners

What you're looking at: A roll-in T-nut drops into an extrusion slot and rotates a quarter turn to lock, and almost every bolt in this chapter pulls against one. The renders show the four extrusions, E, both C beams and D, with every T-nut already in its slot.

Parts:

  • staged: M5 roll-in T-nut ×26
  • staged: M3 roll-in T-nut ×58

Do:

  1. Roll one M5 and one M3 T-nut through each face of all four extrusions.
  2. Mark any face that binds with tape.
  3. Count the fasteners out into labelled trays per the hardware table above.

check Check

Every T-nut you will use rolls in without force; a forced nut galls the channel.

Helper: Counts the T-nuts and bolts into their piles and checks them against the list.

tip Tip

The CAD extrusions are the 250 lengths (E 240, C 350, D 330 mm); yours are the 350 set. Which faces carry nuts, and how many, is what transfers.

Source: LDO Build Notes § Voron 2.4 build FAQ · Voron manual p.85 · Video: Part 4 @0:36:43 · CAD: Voron 2.4r2 STEP @ de7e89d

pause Good stopping point · ~25 min since the last one

bench cleared, sub-assemblies laid out left/right, T-nuts test-rolled and counted into trays. Nothing is assembled; leave the trays covered so nothing gets swept off.

Step 05.5 — Load the E extrusion (XY bridge)

What you're looking at: The E extrusion is the XY bridge: the beam across the back of the gantry that holds the two drive blocks a fixed distance apart and so sets the gantry's width. The eight M5 T-nuts are what those blocks bolt down onto.

Parts:

  • E extrusion ×1
  • M5 T-nut ×8

Do: Slide eight M5 T-nuts into the E extrusion: per end, two in the top slot and two in the bottom slot. None in the side slots. Push them 10–15 mm from the ends, under the drive frame's bolt holes.

check Check

4 nuts at each end: 2 top, 2 bottom, threaded holes facing outward, none jammed.

Source: Voron manual p.85

Step 05.6 — Slide the A drive onto the E extrusion

What you're looking at: The A drive is the right-hand assembly from Ch 04: a stepper motor with its 20 T pulley, wrapped in a printed frame that carries the belt bearing posts. It slides over the end of the bridge extrusion like a sleeve.

Parts:

  • reused: A drive assembly
  • reused: E extrusion with its eight T-nuts

Do: Push the A drive unit onto one end of the E extrusion, motor pointing down. It stays this way up until the flip at Step 05.41. Seat it until the printed part is flush with the extrusion end.

check Check

Plastic flush to the aluminium end face, and the four M5 T-nuts visible through the drive frame's bolt holes.

Source: Voron manual p.85

Step 05.7 — Bolt the A drive to the bridge

What you're looking at: Four M5×10 BHCS pass through the drive frame's flange into the T-nuts underneath. This is what turns the drive block and the bridge into one rigid rear corner; a bolt that spins freely means its T-nut never rolled and the corner is holding on three.

Parts:

  • M5×10 BHCS ×4

Do: Drive four M5×10 BHCS, two into the upper slot and two into the lower, to snug, not torqued. If a bolt spins without pulling, its T-nut has not rolled: back it out and reseat the nut.

check Check

All four bolts bite. The drive frame does not rock on the extrusion.

Source: Voron manual p.86

Step 05.8 — Slide the B drive onto the other end

What you're looking at: The B drive is the left-hand counterpart, not an identical copy: its motor pulley sits at 6.5 mm where the A drive's sits at 16.5 mm, which puts the two belts in separate planes so they can cross without touching.

Parts:

  • reused: B drive assembly

Do: Push the B drive onto the free end of the E extrusion, motor down, flush to the end face. The motor cable exits must point towards each other. If they point apart, the drives are swapped end for end.

check Check

Both motor cable exits face inboard, both printed parts flush.

Source: Voron manual p.86

Step 05.9 — Bolt the B drive and check the bridge

What you're looking at: With both drives bolted on, bridge plus drives is a single rear beam: the fixed back edge of the gantry, and the reference everything else is built to. p.87's lower elevation is the alignment check.

Parts:

  • M5×10 BHCS ×4

Do: Fit the last four M5×10 BHCS, snug. Then compare with p.87's lower elevation: drive frames parallel, and the two pulleys one belt plane apart, one high and one low, as drawn.

check Check

Drives parallel, no twist along the bridge, pulleys one plane apart, all eight M5×10 in and snug. Nothing here is torqued yet.

tip Tip

A's pulley sits high, B's low; p.87's elevation views from behind, A on the left. Never move a pulley to match them: the 10 mm step keeps the belts apart.

Source: Voron manual p.87

pause Good stopping point · ~30 min since the last one

XY bridge bolted to both drive units, all eight M5×10 snug, none torqued. Lay the assembly flat, motors down. Do not start a Y rail: a rail must be centred and screwed down in one sitting.

Step 05.10 — Load M3 T-nuts for the first Y rail

What you're looking at: The two C extrusions are the Y axes, the side rails the X beam slides along. Each carries an MGN9 linear rail on one face. The M3 T-nuts anchor every rail screw; once the rail is down, no more can go in.

Parts:

  • C extrusion ×1
  • M3 T-nut ×9

Do: The 400 mm MGN9H LDO-SLR9H-400Z0 has 20 holes. Mark holes 2, 4 … 18: every other hole from the second, so both end holes stay open, as p.88 asks. Slide in 9 M3 T-nuts, ~25 mm clear of each end.

check Check

9 nuts, one per marked hole, all rolled flat in the channel; holes 1, 19 and 20 unmarked; ~25 mm clear at both ends.

Helper: Counts nine T-nuts into the slot and checks one sits under each marked hole.

Source: Voron manual p.88 · LDO Build Notes § Voron 2.4 build FAQ

Step 05.11 — Centre and start the first MGN9 rail

What you're looking at: An MGN9 rail is a hardened steel guide with a recirculating-ball carriage riding on it. The two printed guides are U-shaped clips that straddle rail and extrusion and hold the rail dead-centred while you start the screws.

Parts:

  • MGN9H 400 mm rail ×1
  • M3×8 SHCS ×9
  • tool: MGN9_rail_guide_x2 jig ×2

Do:

  1. Tape the carriage mid-rail; peel the Ch 00 end-stop bands off with the rail flat.
  2. Sit the rail on the extrusion, centred by an MGN9 guide at each end.
  3. Start holes 2 and 18, then the rest.

Caution

Rev D+ / LDO: "Do not use the holes on the ends of the rails, use the second ones from the ends." src — the manual only requires this on 300 mm builds; LDO requires it on every build, because the end holes sit over the M5/M3 nuts of Step 05.14, which share the rail's slot.

check Check

Rail centred by both jigs; 25 mm from extrusion end to rail end, measured equal at both ends.

Helper: Holds both rail jigs steady on the extrusion while you start holes 2 and 18.

Source: Voron manual p.88 · LDO Build Notes § Voron 2.4 build FAQ · LDO rail-grease guide · Video: Part 3 @1:34:58

Step 05.12 — Tighten the first Y rail

What you're looking at: The same rail, pulled flat onto the extrusion. Tightening from the centre outwards pushes any bow out to the free ends instead of trapping it in the middle. A rail screwed down bowed is a tight spot the carriage hits on every pass.

Parts:

  • reused: M3×8 SHCS ×9

Do: Run every screw finger-tight, re-check the jigs at both ends and the middle, then tighten from the centre outwards in two passes. No torque is specified: firm and even, not maximum. Re-fit a jig afterwards to confirm nothing walked.

check Check

No gap under the rail; the jig slides on at both ends and mid-span; the carriage runs the full length freely.

Source: Voron manual p.88 · LDO rail-grease guide

pause Good stopping point · ~30 min since the last one

first Y rail centred, all its M3×8 screwed down, carriage still on. Tape or stopper the carriage before you walk away.

Step 05.13 — Second Y axis, then load the end M5 T-nuts

What you're looking at: The second Y axis is identical to the first; it becomes the left or right side only when its idler goes on. The M5 T-nuts go into the face opposite the rail, the top face in the machine, for the idler and drive-frame flanges.

Parts:

  • C extrusion ×1
  • MGN9H 400 mm rail ×1
  • M3 T-nut ×9
  • M3×8 SHCS ×9
  • M5 T-nut ×8
  • tool: MGN9_rail_guide_x2 jig ×2

Do: Repeat Steps 05.10–05.12 on the second C extrusion, both rails facing the same way. Then slide two M5 T-nuts into each end of each C extrusion, eight in total, into the slot on the face opposite the rail.

check Check

Two rails equally centred; 2 M5 T-nuts in the top rail-opposite slot at each of the four extrusion ends, none in the rail slot.

Source: Voron manual p.89

Step 05.14 — Load the reserved M5 + M3 pair at each end

What you're looking at: Another M5 and M3 nut at each end, in the rail's own slot, the underside of the Y axis. Both anchor the Ch 06 Z joint bearing block and lower belt clip; the idler and drive frames close these slots permanently.

Parts:

  • M5 T-nut ×4
  • M3 T-nut ×4

Do: At each end of each C extrusion add one M5 T-nut and one M3 T-nut into the rail's own slot, in the bare 25 mm beyond each rail end: M5 outermost, M3 just inboard. Not the top slot.

check Check

Per end: 2× M5 in the top slot, 1× M5 and 1× M3 in the rail slot beyond the rail end.

Helper: Checks every extrusion end: two M5 on top, one M5 and one M3 in the rail slot.

Source: Voron manual p.90

Step 05.15 — Stop the carriages running off

What you're looking at: A linear-rail carriage keeps its ball bearings only while it is on the rail: run it off the end and they scatter. The renders show the Y rails on the undersides of the C extrusions, each with one carriage and a stopper near each end.

Parts:

  • tool: rubber rail stopper ×4
  • consumable: masking tape, if the stoppers run short

Do: Fit a rubber rail stopper, or a doubled tape flag, near each end of both Y rails so a carriage cannot run off. Keep the stoppers: LDO reuses them under the Z joints during the Ch 06 install. src

check Check

Each Y carriage is captive; the manual warns that "dropping the carriage likely irreparably damages it".

tip Tip

The CAD Y rails are MGN9 300 mm; yours are 400 mm (Step 05.10). The stoppers go near the ends wherever those ends are.

Source: Voron manual p.88 · LDO Build Notes § Voron 2.4 build FAQ · CAD: Voron 2.4r2 STEP @ de7e89d

pause Good stopping point · ~30 min since the last one

both Y rails down and tightened, end M5/M3 T-nuts loaded, both carriages captive. Do not fit a backer now: start one only when you can finish it.

Step 05.16 — Unpack and identify the titanium backers

What you're looking at: The titanium backers are three flat drilled strips that bolt to the extrusion face opposite a linear rail. A steel rail on an aluminium extrusion bows as the chamber heats; the titanium strip opposite pulls the other way and cancels most of the bow.

Parts:

  • staged: titanium Y backer ×2 — from Ti backer set
  • staged: titanium X backer ×1 — from Ti backer set
  • staged: M3×8 FHCS ×20 — from Ti backer set
  • staged: M3×6 FHCS ×9 — from Ti backer set

Do: Sort the three backers: the two matching long pieces are the Y backers, the odd shorter one is the X backer. Check they are drilled and countersunk, and count the holes: expect 10 per Y and 9 on X.

check Check

2 Y + 1 X backer, hole counts written down, and you have at least that many M3 T-nuts. The set does not include T-nuts.

Helper: Sorts the backers by length and lays each one beside the rail it matches.

tip Tip

Backer lengths in the picture follow the 250 CAD. Sort by matched pair versus odd one, not by drawn length. A slightly bowed backer straightens as you clamp it down.

Source: Ti extrusion-backers README (tanaes) · Fabreeko backer set · West3D backer set · CAD: Voron 2.4r2 STEP @ de7e89d

Step 05.17 — Fit the first Y backer

What you're looking at: You are working on the bare face of the first Y extrusion, which becomes the top of the Y axis. FHCS are countersunk screws whose heads sink flush into the backer's chamfered holes; a hex key cams out, so use the T10 Torx.

Parts:

  • titanium Y backer ×1 — from Ti backer set
  • M3×8 FHCS ×10 — from Ti backer set
  • M3 roll-in T-nut ×10
  • tool: T10 Torx driver

Do: Turn the first C extrusion rail-down and work on the opposite face. Roll ten M3 T-nuts in, lay the backer on, and start every screw before tightening any. Tighten M3×8 FHCS from the centre outwards, using Torx.

Never on the rail face

the whole point is to put steel on the face opposite the rail and cancel the bending couple. Doubling up on the rail side makes the bow worse. src

check Check

Backer flat along its whole length, every screw seated in its countersink, and both ends clear of where the idler and drive frames land.

Helper: Holds the backer flat on the extrusion while you start every screw.

Source: Ti extrusion-backers README (tanaes) (image x_axis.jpeg)

Step 05.18 — Fit the second Y backer

What you're looking at: The second Y extrusion, same treatment on its rail-opposite face. The first render shows one Y extrusion from underneath, rail face and backer face both in frame. The second shows both Y beams in place: rails underneath on both, backers on top on both.

Parts:

  • titanium Y backer ×1 — from Ti backer set
  • M3×8 FHCS ×10 — from Ti backer set
  • M3 roll-in T-nut ×10

Do: Repeat on the second C extrusion, again on the face opposite its rail. Lay the two finished Y assemblies side by side and confirm they match: rails facing the same way, backers facing the same way.

check Check

Both backers on the rail-opposite face, both flat. Their cable-chain pilot holes end up on the same side of the machine.

tip Tip

The CAD C extrusion is 350 mm with a 300 mm rail (250 machine); yours is the 350-kit C with a 400 mm rail.

Source: Ti extrusion-backers README (tanaes) · CAD: Voron 2.4r2 STEP @ de7e89d

pause Good stopping point · ~35 min since the last one

both titanium Y backers screwed down flat on the rail-opposite face. Check nothing is cammed out before you stop.

Step 05.19 — Fit the front idler to the first Y axis

What you're looking at: The front idler block is the Ch 04 assembly that turns its belt around at the front corner. The blue upper Z-belt clip sits on its serrated top under the two M5×16. In Ch 06 it clamps a Z belt's second end.

Parts:

  • reused: A idler assembly
  • [a]_z_belt_clip_upper_x4 ×1 (blue)
  • M5×16 BHCS ×2

Do:

  1. Take the A idler: FRONT RIGHT, 21.6 mm frame, two M5 holes on top.
  2. Slide it onto the front end of the first C extrusion.
  3. Upper clip over the holes, indent down; two M5×16 BHCS through both.

check Check

Clip flat on the idler top, both bolts biting into T-nuts, idler pulled up tight against the extrusion.

Source: Voron manual p.91 · Video: Part 4 @0:06:41

Step 05.20 — Check flush and notch orientation

What you're looking at: The two front idlers are handed, different parts not mirrored copies: their lower frames differ by 10 mm to match the belt planes. Plastic flush to the end face means the right hand. The clip's notch is the indent that grips the belt.

Parts: none.

Do: Sight the joint from the end: the plastic must sit flush with the end face. A wrong-hand idler will not, so take it off rather than pulling it down with bolts. The clip's notch points away from the idler assembly.

check Check

Plastic flush to the extrusion end, clip notch pointing away from the idler assembly.

Source: Voron manual p.92 · Video: Part 4 @0:08:32

Step 05.21 — Fit the second front idler

What you're looking at: The other front corner, with the opposite-hand idler and its own upper clip. After this the two Y assemblies are complete as sides of the machine: rail, backer, idler and clip on each.

Parts:

  • reused: B idler assembly
  • [a]_z_belt_clip_upper_x4 ×1 (blue)
  • M5×16 BHCS ×2

Do: Same on the second Y assembly with the B idler: FRONT LEFT, the short 11.6 mm lower frame. Push flush, lay an upper clip on top, indent down, then two M5×16 BHCS through both, snug.

check Check

Both Y assemblies have an idler and clip at the front, both flush, both clip notches pointing away from the idler assembly.

Source: Voron manual p.93

Step 05.22 — Offer both Y axes to the drive units

What you're looking at: Now the two sides meet the rear beam. The A drive takes the right-hand side and the B drive the left, so the Ch 04 belt planes reach the corners those belts run to. The result is a U, open at the front.

Parts:

  • reused: both Y assemblies
  • reused: the bridge and drives assembly

Do: Bring each C extrusion into its drive frame: the A idler axis into the A drive, the B-idler axis into the B drive. Push each until the printed frame is flush with the extrusion end, on a flat bench.

check Check

A U-shaped gantry: A idler with A drive on one beam, B with B, both rails and both backers facing the same way.

Source: Voron manual p.94 · Video: Part 4 @0:34:56

Step 05.23 — Bolt the Y axes to the drives

What you're looking at: Two M5×16 per side, down through an upper clip and each drive frame's flange into the rear-end T-nuts, closing the two rear corners. A block not pushed fully home leaves that corner short, and a short corner cannot be squared.

Parts:

  • [a]_z_belt_clip_upper_x4 ×2 (blue)
  • M5×16 BHCS ×4

Do: Per side, lay an upper clip on the drive frame's top flange, indent down. Drive two M5×16 BHCS through clip and flange into the rear M5 T-nuts, snug only. Clip notch points away from the drive assembly.

check Check

Four bolts through two clips, both rear joints flush, both clip notches pointing away from the drive assembly.

Source: Voron manual p.95

Step 05.24 — Sanity-check the gantry frame, then leave it alone

What you're looking at: Four corners, all snug, none torqued. Measuring inside face to inside face at both ends tells you the two Y axes are parallel. The frame can still rack, deforming into a parallelogram, and that freedom is deliberate: Ch 06 squares it in the frame.

Parts: none.

Do: Lay the U-frame flat and measure from the inside face of one Y extrusion to the other, at the bridge and again at the idlers. A difference means a corner block is not pushed home.

check Check

Front and rear spacing equal on the rule. Do not square or lock the gantry now; Ch 06 does it in the frame.

Helper: Reads the rule at the idler end while you read it at the bridge.

Source: Voron manual p.95

pause Good stopping point · ~40 min since the last one

front idlers and both Y axes bolted to the drives, gantry frame sanity-checked and deliberately left slightly loose. Do not tighten anything further; do not start an XY joint (each joint is a bearing stack you must finish in one go).

Step 05.25 — Seat the M5 nuts in both XY joints

What you're looking at: The XY joints are the two printed blocks that ride on the Y carriages. Each is a thick lower body, ~34 mm, plus a thin upper plate, ~16 mm. The right lower body has a moulded wire channel; the left is plain.

Parts:

  • xy_joint_left_lower_MGN12 ×1
  • xy_joint_right_lower_MGN12 ×1
  • M5 nut ×6

Do: Drop three M5 nuts into the hex pockets of each XY joint body, flats aligned to the pocket. Push each fully home with a spare M5 bolt; a proud nut stops the joint closing and cracks the pocket.

check Check

Three nuts per joint, all flush in their pockets, none rotated out of the hex.

Source: Voron manual p.96 · Video: Part 5 @1:18:07 (differs: substitutes Trident-repo parts still in beta at the time)

Step 05.26 — Start the right XY joint bearing stack

What you're looking at: The two upper plates, left and right, carry the same tell as the lower bodies: the right-hand plate has the endstop wire channel. The stack you build on the M5×40 is the belt corner: two F695 flanged bearings, flange-out, between two brass precision spacers.

Parts:

  • xy_joint_right_upper_MGN12 ×1
  • M5×40 SHCS ×1
  • F695 bearing ×2
  • M5 precision spacer ×2

Do:

  1. Keep the right-hand joint's moulded cable path clear and pointing as the page shows.
  2. Push an M5×40 SHCS up through the upper plate.
  3. Thread on bottom to top: spacer, F695 flange down, F695 flange up, spacer.

Caution

Rev D+ / LDO: the manual's "M5 Shim" is the brass M5 precision spacer in this kit, here and everywhere else unless a page is explicitly noted otherwise. src

check Check

Four items on the bolt, reading spacer, flange, plain, plain, flange, spacer from the side; bearings spin freely, cable channel clear.

Source: Voron manual p.97 · LDO Build Notes § Voron 2.4 build FAQ · Video: Part 3 @1:27:47 (differs: pre-release kit had no titanium rail backers)

Step 05.27 — Close the right XY joint

What you're looking at: The lower body comes down over the bearing stack and the M5×40's thread picks up one of its seated M5 nuts. The two halves must close plastic-to-plastic with no gap; a bearing pinched between them drags on the belt until Ch 07 finds it.

Parts:

  • reused: xy_joint_right_lower_MGN12 with its three M5 nuts

Do: Bring the joint body down over the bearing stack so the M5×40's thread enters the nut pocket you loaded at Step 05.25. The two halves must meet with no gap and no bearing pinched between them.

check Check

Halves closed flat, bolt engaged in its nut, bearing stack still turning by finger.

Source: Voron manual p.97 · Video: Part 3 @1:28:26 (differs: pre-release kit had no titanium rail backers)

Step 05.28 — Bolt the right XY joint together

What you're looking at: The other two M5×40 bolts. Three bolts into three captive nuts turn the two printed halves into a single rigid block, which it has to be: belt tension in Ch 07 pulls hard on this corner and tries to prise it open.

Parts:

  • M5×40 SHCS ×2

Do:

  1. Turn the joint over, thin plate up, as p.98 shows.
  2. Drive the two remaining M5×40 SHCS down through the plate into the other two M5 nuts.
  3. Tighten all three evenly and firm: they thread into steel nuts.

check Check

No light between the halves anywhere. The bearing stack still spins.

Source: Voron manual p.98 · Video: Part 3 @1:21:27 (differs: pre-release kit had no titanium rail backers)

Step 05.29 — Fit the right joint's 20-tooth idler

What you're looking at: The 20 T idler is a small toothed pulley running on its own bearing; the toothed side of the belt wraps it. Its M5×40 threads straight into plastic and only holds the idler in place, so it stops the instant the head seats.

Parts:

  • GT2 20-tooth idler ×1
  • M5×40 SHCS ×1

Do: Drop the 20T idler into its pocket and run an M5×40 SHCS down through it. This bolt threads directly into plastic and only positions the idler.

Caution

Do not over-tighten. Stop the moment the head seats and the idler still spins freely; a crushed pocket here shows up as belt noise and premature wear in Ch 07.

check Check

Idler spins under a fingernail flick with no drag and no wobble.

Source: Voron manual p.98 · Video: Part 3 @1:25:58 (differs: pre-release kit had no titanium rail backers)

pause Good stopping point · ~25 min since the last one

right XY joint fully built, bolted and its 20T idler fitted and spinning. Leave the left joint's parts bagged; do not part-build it.

Step 05.30 — Build the left XY joint

What you're looking at: The left joint, built exactly as the right was. The tell is the wire channel: only the right-hand pair has one. If the parts in your hand have a channel, put them down; they are the right joint's.

Parts:

  • xy_joint_left_upper_MGN12 ×1
  • reused: xy_joint_left_lower_MGN12 with its three M5 nuts
  • M5×40 SHCS ×1
  • F695 bearing ×2
  • M5 precision spacer ×2

Do: Mirror of Steps 05.26–05.27: M5×40 up through the upper plate, then spacer, F695 flange down, F695 flange up, spacer. Close the joint body over it into its M5 nut. The left parts have no cable channel.

check Check

Left and right joints sit as mirror images on the bench, not as two of the same hand.

Source: Voron manual p.99

Step 05.31 — Bolt the left joint and fit its idler

What you're looking at: Both joints finished and identical in content: 4× M5×40, 2× F695 between two precision spacers, and one 20 T idler each. Everything meant to spin must still spin freely; drag here becomes belt noise once the belts go on.

Parts:

  • M5×40 SHCS ×3
  • GT2 20-tooth idler ×1

Do: Turn the joint over, thin plate up. Two M5×40 SHCS down through the plate into the remaining M5 nuts, tightened evenly and firm into steel. Then the 20T idler and its own M5×40 into plastic: snug only, must spin.

check Check

Both joints complete: 4× M5×40 each, 2× F695 each, two spacers each, one 20T idler each, all bearing stacks and both idlers free.

Source: Voron manual p.100 · Video: Part 3 @1:31:05 (differs: pre-release kit had no titanium rail backers)

pause Good stopping point · ~20 min since the last one

both XY joints built, bolted and idler-fitted, sitting loose on the bench. Do not slide them onto the X extrusion yet.

Step 05.32 — Load M3 T-nuts for the X rail

What you're looking at: The D extrusion is the X beam, the one the toolhead runs along. It carries an MGN12 rail, wider than the Y rails because it holds the toolhead off one carriage. Same T-nut rule: load them before the XY joints cap the ends.

Parts:

  • D extrusion ×1
  • M3 T-nut ×7

Do: The 400 mm MGN12H LDO-SLR12H-400Z1 has 16 holes. Mark holes 2, 4 … 14: every other hole from the second, so both end holes stay open. Slide in 7 M3 T-nuts, ~15 mm clear of each end.

check Check

7 nuts, one per marked hole, flat; holes 1, 15 and 16 unmarked; clear slot at both ends.

Source: Voron manual p.101

Step 05.33 — Centre and fit the MGN12 rail

What you're looking at: Same centre-and-tighten procedure as the Y rails, with the larger MGN12 guides. This is the rail that decides print quality across X: it must sit centred along its whole length and pull down flat with no gap underneath.

Parts:

  • MGN12H 400 mm rail ×1
  • M3×8 SHCS ×7
  • tool: MGN12_rail_guide_x2 jig ×2

Do: Tape the carriage mid-rail; peel its Ch 00 bands off with the rail flat. Sit the rail on the D extrusion, centred by an MGN12 guide at each end. Start holes 2 and 14, then the rest; tighten centre-outwards.

Caution

Rev D+ / LDO: every other hole from the second here too; both end holes stay open. src

check Check

15 mm of bare extrusion beyond each rail end, equal; the carriage runs the rail with no tight spot and no gap underneath.

Source: Voron manual p.101 · LDO Build Notes § Voron 2.4 build FAQ · LDO rail-grease guide · Video: Part 3 @1:34:46

Step 05.34 — Fit the X backer to the rear face

What you're looking at: The X backer goes on the rear face, the one opposite the rail, same as on the Y axes: steel on one face, titanium on the other, the bows cancelling. The top face stays bare for the XY joints and cable bridge.

Parts:

  • titanium X backer ×1 — from Ti backer set
  • M3×6 FHCS ×9 — from Ti backer set
  • M3 roll-in T-nut ×9
  • tool: T10 Torx driver

Do: Turn the D extrusion so the MGN12 rail faces you. The backer goes on the rear face, opposite the rail, not on top. Roll nine M3 T-nuts in, start every screw, then tighten centre-outwards. Use M3×6 FHCS for X.

Caution

"For X axes, in most cases you'll want to install them on the rear of the X extrusion, opposite the MGN12 rail… If you have a single MGN12 but decide to put a backer on top, you will be actively contributing to the problem of bimetallic expansion!" src

check Check

Backer on the face opposite the MGN12, flat, all screws M3×6 and seated; the top face of the D extrusion still clear.

Source: Ti extrusion-backers README (tanaes) (image fusion_x_chainmount.png)

Step 05.35 — Check backer clearance for the cable chain

What you're looking at: A dry fit. The backers carry pilot holes for the cable chain's end link, and a 3 mm titanium strip may now hold the printed bridge's flat foot off the extrusion. The renders show the chain's fixed end and its run to the bridge.

Parts:

  • staged: cable-chain end link, for a dry fit

Do: Offer the chain's end link up to the X and Y backers and see whether the holes line up and the stock printed bridge sits flat. Do not fit the chain; you are only deciding which bridge to keep.

check Check

You know whether you will use [a]_xy_joint_cable_bridge_2hole or the raised XY_cable_chain_bridge-Igus-3mm_backer. "Igus" = the 2-hole pattern LDO ships. src

tip Tip

The CAD is the 250 machine's; a 350 chain run is longer. Only the face the end link lands on transfers. The raised bridge is a mod part.

Source: Ti extrusion-backers README (tanaes) · LDO cable-chain guide · CAD: Voron 2.4r2 STEP @ de7e89d

pause Good stopping point · ~35 min since the last one

MGN12 rail centred and screwed down on the X extrusion, titanium X backer on the rear face, cable-chain clearance checked. Carriage taped captive.

Step 05.36 — Load the D extrusion's M5 T-nuts

What you're looking at: Six M5 T-nuts in two slots of the X beam: four in the top face the XY joints bolt onto, two in the bottom face for the bolts that come up from underneath. They clamp each joint from both sides so it cannot rock.

Parts:

  • M5 T-nut ×6

Do: In the top slot, at 90° to the rail face, put two M5 T-nuts at each end, four in total. In the bottom slot put one at each end, two in total. Nothing in the rail or backer slots.

check Check

4 + 2 = six M5 T-nuts. The two singles line up with the through-holes the M5×30 bolts will use from underneath.

Helper: Counts the six M5 T-nuts aloud: four in the top slot, two underneath.

Source: Voron manual p.102

Step 05.37 — Slide both XY joints onto the X extrusion

What you're looking at: Each joint's pocket slides over an end of the X beam. This is the first time the X axis exists as one object: beam, rail, backer and both belt corners.

Parts:

  • reused: left XY joint
  • reused: right XY joint

Do: Push a joint onto each end of the D extrusion: left joint to the left end, right joint, the one with the endstop cable channel, to the right. Seat each until the extrusion bottoms out in the joint's pocket.

check Check

Both joints fully home; the two 20T idlers and the two bearing stacks all face the same way along the extrusion.

Source: Voron manual p.103

Step 05.38 — Bolt the joints from above, with the cable bridge

What you're looking at: Bolts through the top of each joint into the beam's top-slot T-nuts. On the right, the cable bridge's foot is sandwiched under the heads, so that side needs the longer M5×16. They stay slightly loose: Ch 06 squares the gantry by nudging these joints.

Parts:

  • M5×10 BHCS ×2
  • [a]_xy_joint_cable_bridge_2hole ×1
  • M5×16 BHCS ×2

Do:

  1. Left joint: two M5×10 BHCS down into the top-slot T-nuts.
  2. Right joint: lay the cable bridge's foot over the same two holes and bolt through both with the longer M5×16 BHCS.
  3. "LEAVE SLIGHTLY LOOSE": lightly tighten.

check Check

Bridge foot flat with its arm standing up on the right-hand side; four bolts started and lightly tightened, none torqued.

Source: Voron manual p.104

Step 05.39 — Bolt the joints from below

What you're looking at: Two more bolts, this time up into the joints from underneath the beam, each with a black washer to spread the load across the plastic. Pulled from both faces the joint cannot rock, but stays lightly tightened until squaring.

Parts:

  • M5×30 BHCS ×2
  • black M5 washer ×2

Do: Turn the X assembly over and run an M5×30 BHCS with a washer under its head up into each of the single M5 T-nuts from Step 05.36. Light tightening again: the joint stays slightly loose until Ch 06.

Caution

Rev D+ / LDO (p.104): "Use the black M5 Washer instead of the M5 Shim cause it looks nicer." This page is the documented exception to the precision-spacer substitution. src

check Check

Two M5×30 in with black washers under the heads, both lightly tightened.

Source: Voron manual p.104 · LDO Build Notes § Voron 2.4 build FAQ

Step 05.40 — Check the X axis assembly

What you're looking at: The finished X axis, checked against the drawing. You are sighting for each belt's two corners at the same height: a corner a millimetre out of plane feeds the belt into the drive pulley at an angle and chews its edge.

Parts: none.

Do:

  1. Left joint: F695 stack upper, 20T idler lower. Right joint: 20T upper, F695 lower.
  2. Sight along the extrusion: left 20T level with right F695, left F695 level with right 20T. Spin all four.

check Check

Left 20T level with right F695, left F695 level with right 20T; nothing binds; the MGN12 carriage still slides freely and is still taped.

Helper: Spins each bearing stack and idler and calls out any that drags.

Source: Voron manual p.105

pause Good stopping point · ~35 min since the last one

both XY joints bolted to the X extrusion top and bottom, cable bridge on, assembly checked against p.105. Still motors-down, the way it runs. The flip is the next step — do not attempt it alone.

Step 05.41 — Turn the gantry upside down

What you're looking at: So far the gantry has been built the way it runs: motors hanging below the bridge, Y rails underneath. Now it goes upside down, motors up and both Y rails facing up, so the X axis can be lowered onto the carriages.

Parts: none.

Do: Turn the gantry over so the A/B motors point up and both Y rails face you. The gantry is now upside down and stays that way through Step 05.48. Get help: it is large and the drives are heavy.

check Check

Motors up, both Y rails and carriages up, nothing dropped on a bearing stack. Left and right are now swapped from where you stand.

Helper: Holds the idler end level while you turn the gantry over.

Source: Voron manual p.106

Step 05.42 — Insert the X axis at an angle

What you're looking at: The X axis drops onto the two Y carriages, the sliding blocks on the Y rails. Tilting it lets you land one joint at a time; lowering it flat means fighting both carriages at once, and a carriage shoved off its rail is ruined.

Parts:

  • reused: the X axis assembly

Do: Tilt the X axis in, one joint onto its Y carriage then the other. The right joint, with the cable bridge, goes on the A drive axis, on your left with the gantry inverted.

check Check

Both joints square on their carriages, bolt holes lined up, nothing fouling the Y extrusion; the MGN12 rail faces the idler end.

Helper: Holds one XY joint on its carriage while you land the other.

Source: Voron manual p.106

Step 05.43 — Bolt the XY joints to the Y carriages

What you're looking at: M3×16 down through each XY joint into the threaded holes in the Y carriage below it. The right joint gets only two: the XY endstop pod fitted at wiring shares its other two holes. The pod's own bolts are M3×30.

Parts:

  • M3×16 SHCS ×6

Do: The left joint takes all four M3×16 SHCS. The right joint takes two only: "2X BOLT ONLY: the remaining bolts will be installed during the end-stop installation." Take all six to snug.

check Check

4 on one joint, 2 on the other, no M3×16 left over. The two empty holes take the pod's M3×30 in Ch 09.

Source: Voron manual p.106

Step 05.44 — Run the X axis end to end

What you're looking at: The first real function test of the gantry as a mechanism. Even, light resistance the whole way means both rails are centred and both carriages sit square. Resistance growing towards one end is racking, a Ch 06 problem, not a rail problem.

Parts: none.

Do: Push the X axis slowly end to end several times, a hand on each XY joint. A tight spot means a rail is not centred; rising stiffness means racking. Do not loosen rails to fix it.

check Check

Full travel both directions, no notch, no rising resistance, both Y carriages moving together. Racking is normal and is corrected in Ch 06.

Helper: Slides the X carriage slowly end to end and reports any rough spot.

Source: Voron manual p.106

pause Good stopping point · ~30 min since the last one

gantry upside down (motors up), X axis in and bolted to both Y carriages, running end to end without binding. It stays upside down into Ch 06. Belts still bagged, XY joint bolts still only lightly tightened — leave both alone.

Step 05.45 — Stage the X-carriage frame halves

What you're looking at: The X carriage is the two-part frame that clamps onto the MGN12 carriage and becomes the mounting plate for the whole toolhead. These are the Clockwork-2 halves, handed so they nest only one way; older X-carriage parts look the same and will not fit.

Parts:

  • staged: x_frame_V2TR_MGN12_left ×1
  • staged: x_frame_V2TR_MGN12_right ×1
  • staged: probe_retainer_bracket ×1

Do: Offer the two carriage halves to the MGN12 carriage and confirm the bolt pattern matches before you commit any heat-set inserts. Then bag them, labelled, with the probe retainer.

Caution

Rev D+ / LDO (p.129–130): "If you are building Clockwork 2 double-check that you have the correct X-Carriage and follow the instructions in the Stealthburner manual." src The carriage goes on with the belts in Ch 07; the toolhead itself is Ch 08.

check Check

Bolt pattern matches the MGN12 carriage; both halves and the probe retainer bagged and labelled for Ch 07.

Source: Voron manual p.129 · LDO Build Notes § Voron 2.4 build FAQ · Video: Part 5 @1:05:47 (differs: substitutes Trident-repo parts still in beta at the time · MGN12 X was a mod then; it is stock on this kit) · CAD: Voron 2.4r2 STEP @ de7e89d

Step 05.46 — Bag what belongs to later chapters

What you're looking at: The XY endstop pod is the blue box carrying the X and Y limit switches on the right XY joint. The renders show both either/or choices pulled apart: the D2F pod and 2-hole bridge are kept, the hall-effect pod and 3-hole bridge are not.

Parts:

  • staged: M3×30 SHCS ×2
  • staged: [a]_endstop_pod_D2F_switch ×1
  • staged: [a]_cable_cover ×1

Do:

  1. Bag the endstop pod with its 2× M3×30 SHCS, labelled.
  2. Bag the [a]_cable_cover and the unused bridge variant separately.

Caution

Rev D+ / LDO: "Our kit includes the XY microswitch PCB, print [a]_endstop_pod_D2F_switch instead of [a]_endstop_pod_hall_effect." src

check Check

Two labelled bags; nothing loose on the bench that Ch 06 or Ch 07 will need.

Helper: Labels the two bags and writes what is inside each one.

Source: LDO printed-parts guide (Rev D) · CAD: Voron 2.4r2 STEP @ de7e89d

Step 05.47 — Stop here: no belts, no squaring

What you're looking at: The gantry is complete as a mechanism and deliberately unfinished as a machine. Belts and squaring are held back because the official squaring procedure begins by releasing A/B belt tension; tension it now and Ch 06 simply undoes it.

Parts: none.

Do: Do not cut, route or tension the A/B belts, do not tighten the XY joints "properly", and do not square the gantry. Ch 06 squares it in the frame, with A/B tension released and the lower Z joints dropped.

check Check

A/B belts still in their bag. XY joint bolts still only lightly tightened.

Source: Voron manual p.107 · Voron docs § V2 Gantry Squaring

Step 05.48 — Log the measurements

(no image — see text)

What you're looking at: The paperwork you will want in Ch 06. The rail overhangs are the evidence that each rail is centred; the two Y-to-Y spacings are the baseline you measure against once the gantry has been squared in the frame.

Parts:

  • tool: pen

Do: Record the rail overhangs you measured, Y and X at both ends, the two Y-to-Y spacings, which face each backer is on, and anything you left deliberately loose.

Measurement Target Yours Notes
Y rail overhang, extrusion 1 — end A / end B 25 / 25 mm
Y rail overhang, extrusion 2 — end A / end B 25 / 25 mm
X rail overhang — end A / end B 15 / 15 mm
Inside Y-to-Y spacing at the bridge —
Inside Y-to-Y spacing at the idlers = at bridge
Backer face — Y1 / Y2 / X top / top / rear
M3×30 SHCS bagged for the endstop pod (p.164) 2

check Check

Numbers written down, not "looked fine". You will want the Y-to-Y spacings when the gantry is squared in Ch 06.

Helper: Writes each gantry measurement into the log as you call it out.

Source: Voron manual p.107 · survey §7.5

pause Good stopping point · ~25 min since the last one

gantry complete and still upside down (motors up), measurements written down, Ch 06/07 parts bagged and labelled. Do not tension belts and do not square the gantry: both are Ch 06/07 and both would be undone.

Checkpoint 05

  • E extrusion joined to both drive units with 8× M5×10 BHCS; drives parallel, no twist
  • Both MGN9 rails centred and tightened on holes 2, 4 … 18, both end holes open, overhang equal at both ends
  • MGN12 rail centred and tightened on holes 2, 4 … 14, both end holes open, overhang equal at both ends
  • Every carriage retained by a stopper or tape; none dropped
  • At each of the four C-extrusion ends: 2× M5 in the top (backer) slot, 1× M5 + 1× M3 in the rail slot beyond the rail end
  • Titanium backers on the face opposite the rail — top of both Y extrusions, rear of the X extrusion — flat, all screws seated, none cammed out
  • Both front idlers and both rear drive joints flush with the extrusion ends, each with a blue upper Z-belt clip under its two M5×16, clip notch pointing away from the idler or drive assembly
  • Both XY joints: 3 M5 nuts, 4 M5×40 SHCS, 2 F695 flange-out between 2 precision spacers, 1 free-spinning 20T idler; the three joint bolts firm, the idler bolt snug
  • Cable bridge fitted to the right XY joint with M5×16 BHCS; left joint on M5×10
  • M5×30 BHCS with black M5 washers underneath, both lightly tightened
  • XY joints bolted to the Y carriages: 4 bolts one side, 2 the other; all six M3×16 fitted; 2× M3×30 SHCS bagged with the endstop pod (p.164) for the right joint's two empty holes
  • X axis runs the full Y travel with no tight spot
  • A/B belts still unopened; nothing squared, nothing torqued down
  • Gantry is upside down (motors up, rails up) with the right joint (bridge, endstop channel) on the A-drive side; it is turned back at Ch 06 Step 06.11
Revali passing a gate
You built a complete gantry with the X axis riding on both Y rails. 12 gummy worms.

Common mistakes

  • Fitting the backers after the gantry is built. Their T-nut slots are capped by the idler and drive frames, and the backer face is buried once the gantry is in the frame. It is a ~3 h teardown to fix (survey §5.2 W2).
  • Putting the X backer on top of the X extrusion. With a single MGN12 on the front face, a top backer adds to the bimetallic bow instead of cancelling it, and it blocks the top slot the XY joints and cable bridge bolt into.
  • Using the rails' end holes. The manual only forbids it on 300 mm builds; LDO forbids it on all of them, because the end holes sit exactly where the M5/M3 T-nuts of p.89–90 and p.102 have to live. Caught late, the rail comes off and goes back on.
  • Forgetting the reserved T-nuts at p.90. Nothing in this chapter uses them, so they are easy to skip — and Ch 06's Z joints and Ch 10's chain hardware then have nowhere to bolt to. Count per slot — 2× M5 in the top slot, 1× M5 + 1× M3 in the rail slot — before the idlers go on.
  • One spacer in an XY joint stack, or a flange facing inward. The pair drops 1 mm and its inner races are never clamped, or there is no belt channel at all; found in Ch 07 as belt rub, and both joints come apart again (3× M5×40 + idler each). Fix: spacer, flange down, flange up, spacer — read it from the side before closing the joint (p.97, p.99).
  • Torquing the XY joints and "squaring" on the bench. The joints are meant to stay slightly loose and the gantry is squared in the frame with the belts slack. Tightening now, or tensioning belts now, costs a full de-tension in Ch 07 (survey §5.2 W1).
  • Leaving the blue upper Z-belt clips off the idlers and drives. Nothing in this chapter loads them, but Ch 06 clamps every Z belt's second end under them (p.117, p.120). Fitting them later means backing out M5×16s on a gantry that is already in the frame.
  • Over-tightening the 20T idler bolts. They thread straight into plastic and only locate the idler. Crushed pockets show up later as belt noise you will blame on tension.

Next

Ch 06 — Z axis: gantry install, Z belts and gantry squaring (manual p.108–123, plus the official 16-step squaring procedure); gated on batch B05 (Z joints + Z chain, 1 plate, 6.4 h) — start it now if it is not already printed. Keep the rubber rail stoppers: LDO uses them under the Z joints to rest the gantry during install.

Source: survey §7.5 · Voron manual p.107