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Chapter 02 — Z drives, Z idlers, Z rails, deck panel

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 four Z drive units, the four Z idlers, the four Z linear rails and the deck panel. When this chapter closes, the frame has a floor, feet, and every part of the Z motion system except the belts and the Z joints — the gantry has somewhere to hang from.

What you're building in this chapter: the machinery that raises and lowers the gantry, one corner at a time. A Z drive is the gearbox in a bottom corner: a printed housing holding three bearings and a shaft, with a big 80-tooth pulley the motor drives through a short closed belt and a 20-tooth pulley the long Z belt runs over — 80:16 of reduction, which is what makes Z fine enough to print with. The housing is two printed halves: a shallow retainer tray the shaft and its bearings drop into, and the deeper main body that closes over them on six long screws and carries the two M5×40 that bolt the drive to the frame. A blue baseplate bolts across the drive's foot face and holds the nut the rubber foot screws into, and a blue cam tensioner pushes the motor along its extrusion to pull the short belt tight. Directly above each drive, at the top corner, a Z idler carries a free-spinning pulley that turns the long belt back down again; its blue slider is the adjuster you tension that belt with in Ch 06 (final tension is set in Ch 14). Between them run the four Z linear rails on the vertical extrusions, the tracks the gantry's corners actually ride on. Last comes the deck panel, the acrylic floor that divides the electronics bay underneath from the print chamber above — it goes in now because once the gantry and the wiring are in, it cannot be lifted out again. Four corners, all identical in function, built from mirrored _a and _b printed parts — diagonal corners share a hand (the map is at Step 02.02).

Revali pointing
The mirrored pair will happily go on the wrong sides. Check the letter you wrote on each.

Time: 4.25–6.25 h hands-on, first build (survey §7.2, less the ~45 min of rail cleaning and greasing, which is done once for all seven rails in Ch 00 Steps 00.18–00.21).

Sessions: 11 × ~30 min — the Pause: lines below break the chapter into 11 segments of 20–55 min; every minute figure is a first-build estimate.

Prerequisites:

  • Chapter 01 complete: frame assembled, squared, bed extrusions positioned 65 mm each side of the printer centreline (130 mm clear gap between their inner faces, 150 mm centre-to-centre) per Ch 01 Step 01.19, and the squareness re-checked after the final torque pass.
  • Print batch B00 (Calibration & jigs) — MGN9_rail_guide_x2.
  • Print batch B01 (Z drive assemblies) — drive bodies, retainers, motor mounts, Z-tensioner brackets, deck supports.
  • Print batch B02 (Accent parts, blue) plates P1 and P3 — the five [a]_ parts below.
  • Steps 02.27–02.28 (16T pulleys, motors onto their mounts) need only B01-P2 and the Motor Kit — B01-P2 is on the shelf long before kit day, so do them the moment the Motor Kit box is open, and label the motor cables then.
  • Chapter 00 complete: all seven rails cleaned, flip-and-packed with grease, wiped and labelled (Steps 00.18–00.21). The four marked Z0–Z3 are used here.
  • Kit boxes open: Motion, Linear Rail Kit, Motor Kit; hardware trays A–C out.

Tools

  • Hex drivers 1.5 / 2 / 2.5 / 3 / 4 mm — good quality, not ball-end for set screws (p.32).
  • Temperature-controlled soldering iron + the LDO brass M3 heat-set tip.
  • Digital caliper (deck-panel thickness gate; 33 mm and 10.7 mm pulley dimensions).
  • Printed jig: MGN9_rail_guide_x2 ×2.
  • Masking tape (carriage retention, rail hole marking, the FRONT label) and a marker. The 3 mm hex key doubles as the rail-gap feeler (Step 02.06).

Consumables: Loctite 243 for any set screw that did not arrive with threadlocker pre-applied. (IPA, grease, soak tray, syringe and cloth were the Ch 00 rail-prep kit — nothing here needs them unless a rail was missed.)

Printed parts — all ASA. Black = main colour, Blue = accent ([a]_ prefix).

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 (Voron-2 STLs/, branch Voron2.4) Bin Qty Colour
Z_Drive/z_drive_main_a_x2.stl 02-Z0 · 02-Z2 2 Black
Z_Drive/z_drive_main_b_x2.stl 02-Z1 · 02-Z3 2 Black
Z_Drive/z_drive_retainer_a_x2.stl 02-Z0 · 02-Z2 2 Black
Z_Drive/z_drive_retainer_b_x2.stl 02-Z1 · 02-Z3 2 Black
Z_Drive/z_motor_mount_a_x2.stl 02-Z0 · 02-Z2 2 Black
Z_Drive/z_motor_mount_b_x2.stl 02-Z1 · 02-Z3 2 Black
Z_Drive/[a]_z_drive_baseplate_a_x2.stl 02-Z0 · 02-Z2 2 Blue
Z_Drive/[a]_z_drive_baseplate_b_x2.stl 02-Z1 · 02-Z3 2 Blue
Z_Drive/[a]_belt_tensioner_a_x2.stl 02-Z0 · 02-Z2 2 Blue
Z_Drive/[a]_belt_tensioner_b_x2.stl 02-Z1 · 02-Z3 2 Blue
Z_Idlers/z_tensioner_bracket_a_x2.stl 02-Z0 · 02-Z2 2 Black
Z_Idlers/z_tensioner_bracket_b_x2.stl 02-Z1 · 02-Z3 2 Black
Z_Idlers/[a]_z_tensioner_9mm_x4.stl 02-Z0 · 02-Z1 · 02-Z2 · 02-Z3 4 Blue
Panel_Mounting/deck_support_3mm_x8.stl 02-deck 8 Black — default (Rev D 350 BOM), see Step 02.12
no render — same clip, slotted for a 4 mm panel Panel_Mounting/deck_support_4mm_x8.stl — 8 Black — fallback if the panel measures 4 mm
Tools/MGN9_rail_guide_x2.stl (jig, not consumed) 00-jigs 2 Black
LDO STLs/z_rail_stop_x4.stl (optional) 02-Z0 · 02-Z1 · 02-Z2 · 02-Z3 4 Black — batch B05, fitted at Step 02.10

The _xN suffix is the quantity you need, not the number of copies in the file — each STL contains one part. _a and _b are mirrored: two drives use the a set, two use the b set.

Hardware — chapter totals.

Fastener / part Qty
M3×8 SHCS 60: 24 drives, 3 per baseplate and 3 per motor mount; 36 Z rails, 9 per rail
M3×16 SHCS 4
M3×40 SHCS 24
M3 hexnut 4
M3 roll-in T-nut, 2020 36 (one per Z-rail screw)
M3×5×4 brass heat-set insert 36 (Steps 02.03–02.04: the first one is Step 02.03's re-check)
M5×10 BHCS 8 (drives)
M5×16 BHCS 4
M5×30 BHCS 12 (idlers: 2 mounting + 1 axle each)
M5×40 SHCS 8
M5 hexnut 4
M5 roll-in T-nut, 2020 28 (16 drives + 8 idlers + 4 deck)
M5 precision spacer, 1 mm (kit substitute for "M5 Shim") 16
M4×4 set screw, pre-applied threadlocker 24 (2 each on 4× 20T, 4× 80T, 4× 16T)
625-2RS bearing 12
GT2 80T pulley, 5 mm ID 4
GT2 20T 9 mm pulley, 5 mm ID 4
GT2 16T pulley, 5 mm ID 6 mm W 4
GT2 20T 9 mm idler, 5 mm ID 4
5×60 mm shaft 4
Gates 2GT closed loop, 6 mm × 188 mm 4
NEMA17 Z motor, LDO-42STH48-2004AC(VRN) 4
MGN9H 400 mm rail, LDO-SLR9H-400Z0 4
Rubber foot, 38×19 mm 4
Deck panel, acrylic black 469×469 1

Quantities cross-checked against the LDO Rev D 350 BOM (350_BOM/Rev_D); the LDO kit ships 6× MGN9H-400 and 1× MGN12H-400 — four of the MGN9s are yours here, the other two are the gantry Y rails in Chapter 05.

Read first

  • The rails were cleaned and greased in Ch 00, not here. Flip-and-pack needs access to the back of the rail, which you lose the moment it is bolted to an extrusion — so if any of Z0–Z3 was missed, fix it before Step 02.06, not after (rail grease guide; survey §4.4 #5, §5.2 W9).
  • The Z motors are the only place in the whole printer that uses 16T pulleys. They look almost identical to the 20T. Get them off the bench when this chapter is done (p.38; survey §4.4 #7).
  • Every set screw gets threadlocker and must land on the flat/D-cut of the shaft. Loose set screws are the single most reported failure on this machine (p.32; §5.2 W12).
  • Two corners take _a parts, two take _b, and diagonal corners share a hand — _a at Z0 (front-left) and Z2 (rear-right), _b at Z1 (rear-left) and Z3 (front-right); map at Step 02.02, dry-fit at Step 02.29. A wrong-hand drive bolts on fine and is only found in Ch 06 when the Z belt goes on and the 20T is not under its idler.
  • Heat-set inserts go into the drive parts before the drive is assembled. A missed insert means taking a finished drive back apart (§4.4 #4, §5.2 W3).
  • The deck panel and its supports go in now, at p.28–30 — not later with the panels. Retro-fitting the deck means pulling the frame apart (LDO note p.29–30; §5.2 W4).
  • Nothing in this chapter touches a probe or an endstop. The Rev D+ nozzle probe and the Omron inductive probe belong to Chapters 08–09; leave both bagged.

Sources for this chapter:

Video coverage (Steve Builds, pre-release LDO kit — differs from Rev D+): Part 1 @3:08:34 (+4m), Part 1 @3:20:00 (+9m), Part 1 @3:28:20 (+7m), Part 1 @3:34:50 (+9m), Part 2 @0:55:00 (+7m), Part 2 @1:18:20 (+14m), Part 2 @1:36:40 (+8m)

Steps

Step 02.01 — Lay out and label the chapter's printed parts

What you're looking at: The printed parts from three batches: the deep z_drive_main body and shallow z_drive_retainer tray that clamp each drive's bearings, the motor mount L-brackets, the blue baseplates and belt tensioners, and the Z idler brackets. Every one exists as a mirrored _a and _b.

Parts:

  • staged: all Chapter 02 printed parts from batches B00, B01 and B02

Do:

  1. Sort the drive parts into *_a and *_b piles, two drives each, against the pair renders above.
  2. Write a or b on the inside face of every part.
  3. Reject any part with a lifted corner or a delaminated bolt boss.

check Check

12 black parts: 4 main, 4 retainer, 4 motor mount, two of each hand; 8 blue accents, 4 idler brackets, 4 sliders, 8 deck clips.

Helper: Sorts the printed parts into the a and b piles and counts them.

tip Tip

Cradles up: the z_drive_main cut corner and its two 9 mm bolt wells sit far from you on _a, near on _b. The retainer cut corner is near-left on _a.

tip Tip

reprint rather than force a warped z_drive_main — it holds the shaft alignment for the whole Z axis. src

Source: Voron manual p.22 · LDO printed parts guide (Rev D) · print plan · Video: Part 1 @3:08:47

Step 02.02 — Learn the four Z positions before you build anything

What you're looking at: Manual p.23 shows the whole Z system: four drives at the bottom corners, four idlers directly above them, four vertical rails and the deck panel. Z0–Z3 is the naming this manual, the kit wiring and its Klipper config all share. See the glossary.

Parts: none.

Do:

  1. Memorise the corners from the front of an upright printer: Z0 front-left, Z1 rear-left, Z2 rear-right, Z3 front-right.
  2. _a builds Z0 and Z2, _b builds Z1 and Z3; each idler takes the hand of the drive below.

check Check

You can point at each of the four corners and say its Z number and its hand without looking.

Helper: Writes Z0 to Z3 on four tape flags and sticks one per corner.

Caution

Rev D+ / LDO: this naming is what the kit's wiring and Klipper config assume — Z0→STEPPER-0, Z1→STEPPER-1, Z2→STEPPER-2, Z3→STEPPER-3 on the Leviathan. Label each motor's cable with a kit cable tag as you fit it in this chapter and you save an hour in Chapter 10. src

tip Tip

The hand map comes from the official CAD, not a manual page. Confirm it by dry-fitting the first drive at Z0 at Step 02.29 before any bolt goes in.

Source: Voron manual p.23 · Voron manual p.40 · LDO wiring guide § Connecting Steppers · Voron-2 CAD Voron_2.4r2_Assembly_STEP.zip @ de7e89d (corner map)

Step 02.03 — Re-check the iron with the LDO tip on the first insert

What you're looking at: Manual p.31: the blue pills are inserts going into Z-drive bosses. Gate B found the iron temperature with the stock conical tip and filled the Heatset_Practice coupon. The LDO tip is different brass, so the first real insert re-checks that number. See the glossary.

Parts:

  • M3×5×4 brass heat-set insert ×1
  • z_drive_retainer_a ×1
  • tool: soldering iron with the LDO brass tip

Do:

  1. Heat the iron to the temperature taped on it at Gate B.
  2. Drive one insert 90 % into the Gate B retainer, then press it flat with a steel block.
  3. Let it cool and inspect it.

Check

The insert went in square in under 5 seconds, sits flush to 0.2 mm proud, and its boss has not bulged.

Caution

Rev D+ / LDO: the kit supplies the brass tip and 153 inserts for the whole build; this one is the first of the 36 in the drive parts, and none go into a coupon. A bulge means 10 °C cooler and a slower push before the next insert, and a reprinted retainer. src

Caution

Iron back in its stand between inserts, bench ventilated. The tip and a freshly set insert both burn: hold parts by the far edge until they cool.

Tip

Do not leave the iron sitting in a part, or powered longer than needed: the brass tip oxidises.

Source: Voron manual p.31 · LDO heat-set insert tool guide · LDO 350 Rev D BOM

Step 02.04 — Seat the heat-set inserts in the Z drive parts

What you're looking at: In front of you are the four retainers and four drive mains. The thirty-six inserts are the threads that hold each drive closed: the six in each retainer's flat face take the M3×40s, the three in the drive's foot face take the baseplate's M3×8s.

Parts:

  • M3×5×4 brass heat-set insert ×35
  • z_drive_retainer_a ×1
  • z_drive_retainer_b ×2
  • z_drive_main_a ×2
  • z_drive_main_b ×2
  • reused: the Gate B retainer with its first insert

Do:

  1. Seat 7 inserts per z_drive_retainer and 2 per z_drive_main, flush; the Gate B retainer takes 6 more. Let each part cool.
  2. Insert pockets are Ø4.7 × 5 mm deep. Ø6 counterbores on the main's flat face take no insert.

Check

36 inserts in, every one flush or a hair below, none cocked, no melted bulge, nothing in a counterbore.

Caution

Iron back in its stand between inserts, bench ventilated. The tip and a freshly set insert both burn: hold parts by the far edge until they cool.

Tip

The retainer's 7 are 6 in the flat print face plus 1 in a side face; the main's 2 are both in one side face.

Tip

Count the Ø4.7 pockets on your own parts before you start; if a part shows a different number, trust the part. A plain M3 clearance hole is Ø3.4 mm.

Source: Voron manual p.31 · LDO heat-set insert tool guide

Good stopping point · ~40 min since the last one

printed parts sorted into a and b piles and inspected, the iron temperature confirmed on the coupon, and all 36 heat-set inserts seated in the four retainers and four drive mains. Unplug the iron. Nothing is assembled.

Step 02.05 — Confirm the four Z rails are already cleaned and greased

What you're looking at: Manual p.24 shows a linear rail and its carriage. These four MGN9H rails are the vertical tracks the gantry's corners ride on. They were degreased and packed with grease in Ch 00, because that job needs the back of the rail. See the glossary.

Parts:

  • staged: MGN9H 400 mm rail ×4, labelled Z0–Z3

Do:

  1. Unbag the four rails marked Z0–Z3; check labels and carriage tape.
  2. Run each carriage end to end: smooth and silent, not dry or notchy.
  3. Work over the bench, never the floor: a dropped carriage is scrap.

check Check

Four labelled rails on the bench, carriages taped or stoppered, each smooth and silent over full travel, no grease on any rail's outside.

Helper: Runs each carriage end to end over the bench and says smooth or notchy.

Caution

Rev D+ / LDO: the kit does not include grease, and the rails ship with a shipping oil rather than a lubricant. If you do have to prep a rail here, use NLGI 0 or NLGI 1 — Super Lube 21030, Mobilux EP1/EP2, or white lithium — never a thin oil or a PTFE dry lube. src

tip Tip

If a rail was missed, do Ch 00 Steps 00.18–00.20 on it now and let it dry completely before it goes near the frame.

Source: Voron manual p.24 · LDO rail grease guide · LDO Build Notes (Rev D)

Step 02.06 — Fit the first Z rail, centred, with the MGN9 guides

What you're looking at: Manual p.25 shows a rail going onto a vertical extrusion, with the printed rail guides drawn in green. The guides straddle rail and extrusion and hold the rail centred on the 20 mm face while you start the screws.

Parts:

  • MGN9H 400 mm rail ×1
  • M3×8 SHCS ×9
  • M3 roll-in T-nut ×9
  • MGN9_rail_guide_x2 jigs ×2
  • tool: 3 mm hex key as the gap feeler

Do:

  1. Slip a MGN9_rail_guide over each rail end.
  2. Pre-load nine M3 T-nuts in the front-left vertical's rear-looking face.
  3. Rest the rail on a 3 mm hex key and start nine screws finger-tight in holes 2, 4 … 18.

check Check

Rail centred on the front-left vertical's rear-looking face, sitting on the 3 mm key, all nine screws started, both end holes empty.

Caution

Rev D+ / LDO: p.25 draws a screw in every other hole from the end hole. LDO's "do not use the holes on the ends of the rails" is written for p.88; the survey applies it to every rail (§4.4 #6). So shift one hole in: holes 2, 4 … 18, leaving 1, 19 and 20 empty. src

tip Tip

Tape-mark the nine holes before you start. Test-fit each T-nut: if one jams, swap the nut, not the face. On the rear verticals the rail faces forward.

tip Tip

Peel the two end-stop bands from Step 00.17 only with the rail lying flat on the bench, never on edge or with the carriage near an end.

Source: Voron manual p.25 · LDO Build Notes (Rev D)

Step 02.07 — Tighten from the centre outward

What you're looking at: Manual p.25 again: the same rail, now being tightened. Working outward from the middle presses the rail flat against the extrusion. Starting at one end walks a bow along the rail, and a bow is the tight spot you feel later.

Parts:

  • reused: the first Z rail and its nine started screws

Do:

  1. Tighten from the middle of the rail outward, alternating up and down. Snug, not gorilla-tight: an M3 into a T-nut will strip.
  2. If a tight spot shows, back the screws off and re-tighten from the centre.

check Check

With the guides removed, the carriage feels identical at every point over the rail's full length. Any tight spot means the rail is not flush.

Source: Voron manual p.25 · Voron manual p.24

Step 02.08 — Secure the carriage before the printer is turned over

What you're looking at: Manual p.26: the carriage and the risk. The carriage rides on recirculating ball bearings retained only by the rail, so it must be tethered before the frame is inverted. A carriage that runs off the end spills its balls and is scrap.

Parts:

  • consumable: masking tape, or the rail's plastic shipping stoppers

Do: Tape the carriage to the rail, or refit the plastic shipping stopper, so gravity cannot walk it off the end. The printer goes upside down at Step 02.11 and an untethered carriage slides off the bottom end.

check Check

The carriage cannot move to the end of the rail under its own weight.

Source: Voron manual p.26

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

the first Z rail is centred, tightened centre-outward, verified smooth over full travel, and its carriage is taped. A rail is a self-contained unit; stop only with one finished, never with half its screws started.

Step 02.09 — Install the remaining three Z rails

What you're looking at: Manual p.27: all four Z rails on their verticals. Read the graphic for the mounting face, not the pairing. The two left rails face each other across the machine's depth, and the two right rails do the same.

Parts:

  • MGN9H 400 mm rails ×3
  • M3×8 SHCS ×27
  • M3 roll-in T-nut ×27

Do: Repeat Steps 02.06–02.08 on the other three verticals. Each rail faces the other rail on its own side: front-left faces rear-left, front-right faces rear-right. Keep the same 3 mm bottom gap and holes 2–18 on all four.

check Check

Four rails installed, the two rails on each side pointing at each other, all four bottom gaps equal, every carriage taped and running smoothly.

Helper: Tape-marks holes 2, 4 and on to 18 on each rail before its screws go in.

Caution

Manual p.27 says only "make sure the rails face each other as shown in the graphic" and leaves the pairing to the drawing. The official CAD at the pinned commit de7e89d says every Z rail's mounting face is normal to ±Y: the two rear rails face forward, the two front rails face rearward. Corrected 2026-09-05. src

tip Tip

The CAD is the 250 machine: MGN9 300 mm rails on 430 mm verticals. Yours are MGN9H 400 mm on 350 verticals; the mounting face is the same.

Source: Voron manual p.27 · CAD-render pilot §8 — Z rail orientation · Voron-2 CAD Voron_2.4r2_Assembly_STEP.zip @ de7e89d · CAD: Voron 2.4r2 STEP @ de7e89d

Step 02.10 — Optional: fit the LDO rail stops at the top of each Z rail

What you're looking at: The grey render is the LDO rail stop, a printed clip that caps a rail's top end so a carriage cannot run off during the gantry install in Ch 06. It clips to the free top length above the carriage.

Parts:

  • z_rail_stop_x4 ×4

Do: Fit a stop to the top of each Z rail now, while the rails are accessible. Skip them and the tape from Step 02.08 covers you until Ch 06.

check Check

A stop on each of the four rails, or a decision to skip them with the tape left in place.

tip Tip

LDO also uses a rubber rail stopper under the Z joints as a gantry rest at manual p.114–116. That is Chapter 06 — do not confuse the two. src

tip Tip

The CAD rail is MGN9 300 mm on a 430 mm vertical, leaving ~107 mm bare above it. The stop clips to the rail end, not to a dimension.

Source: LDO printed parts guide (Rev D) · LDO Build Notes (Rev D) · CAD render — assets/cad/PILOT.md · Video: Part 4 @1:27:15 · CAD: Voron 2.4r2 STEP @ de7e89d

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

all four Z rails are on, facing each other, sharing the same ~3 mm bottom gap and hole pattern, every carriage taped or stoppered. The frame is still the right way up. Do not turn it over until the carriages are secured.

Step 02.11 — Turn the printer upside down and pre-load the deck T-nuts

What you're looking at: Manual p.28: the frame inverted, with four M5 roll-in T-nuts dropped into the top slots of the two bed extrusions. The printer spends the next fifteen manual pages upside down because every Z drive bolts to the underside of the bottom frame rails.

Parts:

  • M5 roll-in T-nut ×4

Do: Confirm every carriage is taped, then turn the frame upside down onto the flat reference surface. Slide four M5 T-nuts into the upward-facing slots of the two bed extrusions, two per extrusion, where the deck panel's holes will land.

check Check

Frame sits flat and does not rock in this orientation; four T-nuts in, free to slide, none dropped inside an extrusion.

Helper: Takes the other side of the frame as it turns over, then counts the four T-nuts in.

tip Tip

Load the 16 drive-corner M5 T-nuts now too, four per bottom corner, two in each extrusion that meets there. Test-fit each slot: LDO's T-nut tolerance note applies. src

Source: Voron manual p.28

Step 02.12 — Caliper the deck panel and choose the support thickness

What you're looking at: Manual p.28: the deck panel, the acrylic floor separating the electronics bay below from the print chamber above. See the glossary. The render is one printed support clip; its slot must match the panel's thickness.

Parts:

  • staged: deck panel ×1
  • staged: deck_support_3mm_x8 ×8
  • staged: deck_support_4mm_x8 ×8, only if the panel measures 4 mm
  • tool: caliper

Do: Measure the actual thickness of your deck panel with the caliper, in three places. Do not resolve this from documents. Pick the clip set that matches what you measured; the clips go in at Step 02.14, after the panel.

check Check

Three readings agree within 0.1 mm, the number is in your build log, and eight clips of the matching thickness are on the bench.

Helper: Reads the caliper display aloud three times so you can pick the clip.

Caution

Rev D+ / LDO: LDO's build note for p.29–30 says the LDO deck panel is 4 mm nominal — use deck_support_4mm, but the Rev D 350 BOM lists it as 469×469×3 mm. The size-specific 350 BOM wins, so B01 prints the 3 mm set. Measure, fit whichever matches, reprint the other if you have to. src · BOM

Source: Voron manual p.28 · LDO Build Notes (Rev D) · LDO 350 Rev D BOM · Video: Part 2 @0:56:54

Step 02.13 — Drop the deck panel in, notch to the back

What you're looking at: Manual p.28: the deck panel dropping onto the bed extrusions. Cut 469 mm, 1 mm under the frame's opening, it sits inside the frame on them. The round hole passes the bed cables, the notch the Z-chain bundle.

Parts:

  • deck panel ×1

Do:

  1. Peel any protective film.
  2. Lower the panel into the bottom frame's opening, cut-out notch toward the back, flat on both bed extrusions.
  3. Line the four bolt holes up over the four T-nuts.

check Check

Notch at the back. Panel inside the frame opening, flat on both bed extrusions, sunk 16–17 mm below the rails' upward faces, no rock.

Helper: Holds the far edge of the deck panel level as it lowers into the frame.

Source: Voron manual p.28 · LDO 350 Rev D BOM

Step 02.14 — Fit the deck support clips

What you're looking at: One deck_support clip: a small T-tab, about 20 × 14.5 × 5.8 mm, with a ledge. The manual never draws them. Once the printer is upright, the panel hangs under the bed extrusions and these eight ledges carry it until Ch 09 bolts it.

Parts:

  • deck_support_3mm_x8 ×8

Do:

  1. Push a clip's tab end-on into the inward-facing slot of a bottom-frame extrusion above the panel edge, then twist it 90° so the ledge lies over the panel.
  2. Two per side, evenly spaced (verify on bench).

check Check

Eight ledges over the panel edge, all the same thickness variant; the panel cannot be lifted out of the frame.

Caution

Rev D+ / LDO: this step is not in the official manual at all. LDO adds it here: "This is a good time to install the deck supports." Doing it later means the deck comes out and the frame comes partly apart (§5.2 W4). src

Source: Voron manual p.29 · LDO Build Notes (Rev D) · Video: Part 2 @0:56:54

Step 02.15 — Line the four M5 T-nuts up under the deck holes and stop there

What you're looking at: Manual p.29: the four T-nuts sitting under the four holes in the deck, and nothing else. The bolts that go through those holes also clamp the two DIN rails that carry the electronics, so they belong to one step in Ch 09.

Parts:

  • reused: the four deck T-nuts

Do:

  1. Slide each T-nut directly under one of the four deck-panel holes, then leave them there.
  2. No bolts and no DIN rails yet: both go on in Ch 09 Step 09.5.

check Check

Four T-nuts visible through the four deck holes, free to nudge but not lost inside an extrusion. Panel sitting flat, unbolted, notch to the back.

tip Tip

If a DIN rail's own slots will not line up when you get there, Ch 09 shortens the DIN rail rather than moving the panel. src

Source: Voron manual p.29 · LDO wiring guide § Installing the DIN Rails and Wire Ducts

Step 02.16 — Fix the printer's orientation in your head

What you're looking at: Manual p.30: the orientation cube the manual prints on every graphic from here on. With the printer inverted, front and back stop being obvious, and every "which corner" callout for the rest of the chapter is read against that marker.

Parts: none.

Do: Put a strip of masking tape on the front bottom frame rail, the one the front ends of the two bed extrusions run into, and write "FRONT" on it.

check Check

Front face marked, and you can restate the Z0–Z3 map from Step 02.02 with the printer inverted.

Helper: Writes FRONT on the tape strip and sticks it on the front bottom rail.

Source: Voron manual p.30

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

the printer is inverted and stable, the deck panel is in with its notch to the back and captured by eight support clips of the measured thickness, the four M5 T-nuts sit under the deck holes, and the FRONT tape is on. Leave the deck unbolted: those four bolts belong to Ch 09 Step 09.5.

Step 02.17 — Fit the 20T pulley to the 5×60 shaft, 33 mm out

What you're looking at: Manual p.32: the Z drive's shaft assembly. The 5 × 60 mm shaft is the drive's axle; the 20T pulley is what the long Z belt runs over. A set screw is a headless screw that clamps a pulley to a shaft.

Parts:

  • 5×60 mm shaft ×1
  • GT2 20T 9 mm pulley ×1
  • M4×4 set screws ×2 (pre-threadlocked)

Do:

  1. Slide the 20T pulley on so 33 mm of shaft protrudes on the long side.
  2. Rotate until you see the D-cut flat down a set-screw hole.
  3. Fit both set screws with a hex driver, not a ball-end.

check Check

One set-screw hole showed the flat before the screws went in; 33 mm from the long shaft end to the pulley's near flange.

Helper: Reads the caliper aloud: 33 mm from the long shaft end to the pulley.

Caution

Rev D+ / LDO: the kit's M4×4 set screws arrive with threadlocker pre-applied — do not add more. If a screw has clearly been used before or has no visible compound, add Loctite 243 and keep it off the printed parts. src

Source: Voron manual p.32 · LDO 350 Rev D BOM

Step 02.18 — Verify the pulley at 33 mm, then repeat ×4

What you're looking at: Manual p.32's set-screw panel: both set screws in, one on the D-cut flat. The same 33 mm on all four shafts puts the four 20T pulleys in one plane, so the four corners lift evenly.

Parts:

  • 5×60 mm shaft ×3
  • GT2 20T 9 mm pulley ×3
  • M4×4 set screws ×6
  • tool: caliper

Do: Caliper the first pulley at 33 mm from the long shaft end to its near flange, then build the other three shaft/pulley pairs the same way.

check Check

Four shafts, four 20T pulleys, all at the same protrusion, all with a set screw on the flat, all eight set screws tight.

Helper: Reads the caliper aloud on each of the four shafts: 33 mm.

Source: Voron manual p.32 · Voron-2 STLs/Tools

Step 02.19 — Build the bearing/pulley stack on each shaft

What you're looking at: Manual p.33: the full stack on the shaft. Three 625-2RS bearings, plain 5 × 16 × 5 mm ball bearings, carry the shaft; the 80T pulley is what the short 188 mm belt drives, and the brass precision spacers set the spacing. See the glossary.

Parts:

  • 625-2RS bearings ×12
  • GT2 80T pulley ×4
  • M5 precision spacer 1 mm ×16
  • reused: the four shafts with their 20T pulleys

Do: On each shaft, outward from the 20T pulley: a 625 on its collar side; on the other side two M5 spacers, a 625, two spacers, 80T pulley, the last 625 at the end. Press by hand, inner race only.

check Check

Your stack matches the p.33 graphic: both outer bearings spin free, no spacer trapped crooked, the 80T running true with no rim wobble.

Caution

Rev D+ / LDO: the manual says "M5 Shim". The kit supplies brass M5 precision spacers instead — use those, everywhere in the manual from p.19 onward unless a note says otherwise. Four per drive, 16 for this chapter. src

Source: Voron manual p.33 · LDO Build Notes (Rev D) · Video: Part 2 @0:06:45

Step 02.20 — Threadlock the 80T pulley set screws and check your work

What you're looking at: Manual p.33: the 80T pulley's two set screws. This is the joint the entire weight of the gantry hangs on through the belt, and loose set screws are the most-reported failure on this machine, so both get threadlocker and one lands on the flat.

Parts:

  • M4×4 set screws ×8

Do: Two set screws per 80T pulley. Set the 80T pulley so a set screw meets the shaft's flat, fit both set screws with threadlocker, and tighten. Build all four stacks.

check Check

Four complete shaft assemblies, all matching the graphic, none able to slip when you twist the 80T pulley against the shaft by hand.

Source: Voron manual p.33 · Video: Part 1 @3:46:04

Step 02.21 — Fit the 188 mm closed belt loop over the 80T pulley

What you're looking at: Manual p.34: the closed 188 mm belt loop dropped over the 80T pulley. It is a continuous loop with no join, so it has to be threaded on before the drive is closed.

Parts:

  • Gates 2GT closed loop 6 mm × 188 mm ×4

Do: Drop one closed belt loop over each 80T pulley, teeth inward, before the shaft goes into the housing. The loop has no join, so this is the only moment it can go on.

check Check

Four loops, each seated in its 80T pulley's teeth, hanging free, not twisted.

Caution

Rev D+ / LDO: LDO publishes no deviation for the Z belt loop, the 16T/80T pulleys or the Z gear ratio — the Build Notes for p.22–51 cover only p.29–30 (deck supports) and p.39 (stepper wiring). The kit's Klipper config confirms the stock arrangement: [stepper_z] rotation_distance: 40, gear_ratio: 80:16. Use the 188 mm loops as supplied. src

Source: Voron manual p.34 · LDO Build Notes (Rev D) · LDO Klipper config leviathan-printer-rev-d-sbv2.cfg · Video: Part 1 @3:29:28

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

four complete shaft assemblies: 20T pulleys at 33 mm, bearing and precision-spacer stacks built, 80T pulleys threadlocked, and the 188 mm belt loops hung on. The bearings are only slid onto the shaft here, so nothing is mid-assembly. Do not start Step 02.22 until you can close a drive in one sitting.

Step 02.22 — Seat the shaft assembly into z_drive_retainer (the shallow half)

What you're looking at: Manual p.35: the shaft assembly lowering into z_drive_retainer, the shallow tray half of the housing, 16 mm deep, with six brass inserts in its flat outer face. Its three half-round cradles take the 625 bearings; the deeper z_drive_main clamps them from the other side.

Parts:

  • reused: one z_drive_retainer_a with its inserts
  • reused: one belted shaft assembly

Do:

  1. Start with an _a retainer: inserts down, cradles up.
  2. Lower the shaft assembly so each 625 drops into a cradle, the loop in the pocket.
  3. If one will not seat by hand, do not heat or hammer.

check Check

All three bearings down in their cradles, the shaft parallel to the retainer's flat face, and the belt loop lying in the pocket.

Source: Voron manual p.35

Step 02.23 — Check the shaft position against the section view

What you're looking at: Manual p.35's section view beside your part. The section is the only place the manual shows which side of the 20T pulley each spacer and bearing belongs on: after the main goes on, six long screws have to come back out to fix it.

Parts: none.

Do: Hold your part next to the isometric and section views. Confirm the 20T pulley is on the same side, the spacer stack sits between the same two bearings, and the shaft ends are flush the same way.

check Check

Your assembly and the drawing are indistinguishable. Fix it now: after the main goes on, six M3×40 have to come back out.

Helper: Holds the drive beside the page and names any difference from the section view.

Source: Voron manual p.35

Step 02.24 — Close the drive with z_drive_main and six M3×40

What you're looking at: Manual p.36: z_drive_main, the deeper half, closing over the shaft. Its flat face has six counterbored holes, no inserts, and a rectangular window that clears only the 80T rim. The six M3×40 run through both halves and bite the inserts in the retainer's outer face.

Parts:

  • M3×40 SHCS ×6
  • reused: one z_drive_main_a with its side inserts

Do:

  1. Lower the main over the shaft, counterbores up, halves meeting with no gap.
  2. Drive the six M3×40 SHCS through the counterbores into the retainer's inserts, criss-cross. Snug, then stop.
  3. Every head must sink into a counterbore.

check Check

Six heads down in their counterbores, no gap along the joint line, and the shaft still spins freely by hand with the belt on.

tip Tip

If the shaft binds, a bearing is trapped crooked: back the screws off and reseat.

Source: Voron manual p.36 · Video: Part 1 @3:29:31

Step 02.25 — Fit the blue baseplate and its captive M5 nut

What you're looking at: Manual p.37: the blue [a]_z_drive_baseplate, with an M5 hex nut dropped into a pocket on its plain face, the face that goes against the drive. That captive nut is the thread the rubber foot's M5×16 screws into.

Parts:

  • [a]_z_drive_baseplate_a ×1
  • M5 hexnut ×1
  • M3×8 SHCS ×3

Do:

  1. Turn the baseplate plain-face up, drop the M5 hexnut into the pocket.
  2. Flip it straight onto the drive's foot face, pocket down, C-notch over an M5 well.
  3. Secure with three M3×8 SHCS from the counterbored face.

check Check

Nut trapped behind the plate and unable to spin, plate flat on the drive with no rock, three M3×8 heads sunk in their counterbores.

tip Tip

Counterbored face up, C-notch opening to your left: the notch is far-left on _a, near-left on _b. Match the baseplate to the letter on its drive.

Source: Voron manual p.37

Step 02.26 — Confirm the belt loop is captured

What you're looking at: Manual p.37: the assembled drive with the belt loop visible inside it. The loop leaves the housing through the retainer's rectangular window, the face with the six insert heads, and must hang out far enough to hook over the motor's 16T.

Parts:

  • M3×40 SHCS ×18
  • M3×8 SHCS ×9
  • M5 hexnut ×3
  • [a]_z_drive_baseplate_a ×1
  • [a]_z_drive_baseplate_b ×2
  • reused: the other three retainers and mains
  • reused: the other three belted shaft assemblies

Do:

  1. Look through the retainer's window: the closed loop circles the 80T inside, with slack hanging out to reach the motor pulley.
  2. Repeat Steps 02.22–02.26 until all four drives are closed, two a and two b.

check Check

In every drive the belt is visible inside and free to move; four drives closed.

Source: Voron manual p.37

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

all four drives closed: shafts seated, retainers down on six M3×40 each, blue baseplates on with their captive M5 nuts, belt loops captive and free. Each drive is one ~9-minute unit, so if you stop earlier, stop with a drive fully closed and its baseplate on — never with a drive half-closed.

Step 02.27 — Fit the 16T pulley to a Z motor at 10.7 mm

What you're looking at: Manual p.38: a Z stepper motor with its 16T pulley. The Z motors are the only place in this printer that uses 16T. The 20T pulleys elsewhere look identical, and fitting a 20T here silently changes the gear ratio the firmware assumes. See the glossary.

Parts:

  • NEMA17 Z motor LDO-42STH48-2004AC ×4
  • GT2 16T pulley ×4
  • M4×4 set screws ×8

Do:

  1. Check the tooth count: the only 16T pulleys in the printer.
  2. Slide one on each motor so motor face to pulley underside is 10.7 mm.
  3. Rotate so a set screw meets the flat; tighten both with threadlocker.

check Check

On all four, 10.7 mm on the caliper, the tooth band level with the 80T it will drive, no slip under hand force.

Helper: Counts each pulley's teeth to 16 and reads the 10.7 mm caliper aloud.

tip Tip

when all four are done, physically remove every remaining 16T pulley from the bench so one cannot end up on an A/B motor in Chapter 04. src

tip Tip

The pulley may sit better flipped, depending on the motor. What matters is where the teeth end up, not which way the boss faces.

Source: Voron manual p.38 · LDO Build Notes (Rev D) · Video: Part 2 @1:15:06

Step 02.28 — Bolt the motor to z_motor_mount, watching the cable exit

What you're looking at: Manual p.39: the motor bolted to z_motor_mount, the L-bracket that stands the motor off the frame. The mounts are mirrored _a / _b, and the two hands put the motor's cable exit on opposite sides. Three screw holes only: the fourth corner is open by design.

Parts:

  • z_motor_mount_a ×2
  • z_motor_mount_b ×2
  • M3×8 SHCS ×12
  • reused: the four Z motors with their 16T pulleys

Do:

  1. Set the motor's round boss in the plate's half-round notch, cable exit oriented as in the graphic.
  2. Fit three M3×8 SHCS through the plate's counterbored holes into the motor.
  3. Build all four: two a mounts, two b.

check Check

All four cable exits point the same way relative to their mount, the 16T clears the mount, the foot's two M5 clearance holes unobstructed.

Caution

Rev D+ / LDO: the manual's own stepper wiring instructions do not apply to this kit. Wire the Z steppers per the LDO Rev D wiring guide (Z0 front-left→STEPPER-0, Z1 rear-left→STEPPER-1, Z2 rear-right→STEPPER-2, Z3 front-right→STEPPER-3). Label each motor cable now: in Chapter 10 the four are indistinguishable. src · wiring guide

tip Tip

Stood on its print face, thick foot arm on your right running toward you: the thin motor plate is the far edge on _a, the near edge on _b.

Source: Voron manual p.39 · LDO Build Notes (Rev D) · LDO wiring guide § Connecting Steppers · Video: Part 2 @1:19:26

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

four Z motors carry their 16T pulleys at 10.7 mm and are bolted to their a/b mounts with the cable exits matched. Get every remaining 16T pulley off the bench before you walk away, and leave the motor cables labelled.

Step 02.29 — Identify Z0 and start there

What you're looking at: Manual p.40: the highlighted corner is Z0, front-left. The mirror hand of the printed parts decides which corner an assembly fits, so the drive and motor mount are matched to the corner before a single bolt goes in.

Parts:

  • reused: one complete _a drive
  • reused: one _a motor and mount assembly

Do:

  1. Find the front-left corner from the FRONT tape; lay an _a drive and motor assembly beside it.
  2. Dry-fit first: retainer face toward the motor's extrusion, counterbore face outboard over the side rail, 16T in line with the 80T.

check Check

An _a drive and motor dry-fitted at front-left: retainer face toward the motor's extrusion, counterbore face outboard over the side rail, baseplate up.

tip Tip

If the dry-fit only works with the _b parts, the map is reversed. Swap every _a for _b for the rest of the chapter and write that in the build log.

Source: Voron manual p.40 · Voron manual p.41 · Voron-2 CAD Voron_2.4r2_Assembly_STEP.zip @ de7e89d (corner map)

Step 02.30 — Pre-load four M5 T-nuts at the Z0 corner

What you're looking at: Manual p.41: four M5 roll-in T-nuts loaded into the two bottom extrusions meeting at this corner. They are the threads for everything that bolts down here: two for the drive body's M5×40, two for the motor foot's M5×10. The drive-end one also pins the cam.

Parts:

  • M5 roll-in T-nut ×4

Do:

  1. Slide four M5 T-nuts into the two extrusions at this corner, two in each.
  2. Two M5×40 go into the side rail; two M5×10 lie along the front or rear rail, 25 mm apart. Z0/Z3 front, Z1/Z2 rear.

check Check

Four T-nuts in, two per extrusion, all free to slide, none jammed or dropped inside the extrusion.

tip Tip

Skip the loading if you pre-loaded this corner's T-nuts at Step 02.11.

Source: Voron manual p.41 · LDO Build Notes (Rev D) · Voron-2 CAD Voron_2.4r2_Assembly_STEP.zip @ de7e89d (which rail takes which bolts)

Step 02.31 — Bolt the drive body down with two M5×40

What you're looking at: Manual p.41: the finished drive landing in the corner on two long M5×40 that run down the body's two 35 mm wells into the T-nuts. The drive is the fixed half: its two bolts go fully tight now.

Parts:

  • M5×40 SHCS ×2
  • reused: the completed _a drive

Do:

  1. Set the drive baseplate up, retainer face toward the motor's extrusion, counterbore face outboard.
  2. Drop both M5×40 down the deep wells into the side-rail T-nuts, pull the body hard into the corner, tighten both fully now.

check Check

Body hard against both extrusions, both M5×40 tight; the 188 mm loop hanging out of the retainer's window over the motor's extrusion.

tip Tip

The p.42–43 DON'T TIGHTEN applies to the two M5×10 in the motor foot. Those are the only bolts at this corner that stay loose.

Source: Voron manual p.41

Step 02.32 — Slide the motor assembly in at an angle

What you're looking at: Manual p.42: the motor and its mount sliding in beside the drive at an angle, with the hanging belt loop hooked over the 16T on the way in. That angled entry is the only path that gets the loop onto both pulleys.

Parts:

  • M5×10 BHCS ×1
  • reused: the _a motor and mount assembly

Do:

  1. Hold the motor/mount at an angle, hook the loop over the 16T, slide the foot onto the extrusion beside the drive.
  2. Fit one M5×10 BHCS through the foot hole farthest from the drive and leave it loose.

check Check

Loop squarely in both the 16T and 80T tooth bands, motor foot flat on the extrusion, motor-end screw loose, drive-end foot hole empty.

Source: Voron manual p.42

Step 02.33 — Fit the blue belt tensioner, still loose

What you're looking at: Manual p.43: the blue [a]_belt_tensioner, a cam whose lobe lies in a pocket under the drive end of the motor foot. The lobe is eccentric: swinging the tab from upright to flat pushes the motor foot away and takes up the belt slack.

Parts:

  • [a]_belt_tensioner_a ×1
  • M5×10 BHCS ×1

Do:

  1. Slide the cam's lobe flat-face-down into the 4 mm pocket under the foot's drive end, hole over the foot's empty hole.
  2. Fit the second M5×10 BHCS through both and leave it loose: a pivot, not a fastener.

check Check

Tab free to swing about the screw; motor still free to slide along the extrusion; both M5×10 in the foot loose.

tip Tip

Flat face down, round lobe on your left: the upright tab is far-right on _a, near-right on _b. The wrong hand swings away from the motor.

Source: Voron manual p.43 · Video: Part 2 @1:18:50

Step 02.34 — Flip the tensioner latch closed

What you're looking at: Manual p.44: the cam being rotated closed. Closing it is what tensions the belt; the arrow on the page is the direction that pushes the motor foot away from the drive body. The tab ends flat in the notch in the foot's outer edge.

Parts: none.

Do: Swing the tab toward the motor, in the direction of the p.44 arrow, until it lies flat and seats in the notch. The lobe moves the motor foot ~2–3 mm away from the drive body, which must not move.

check Check

Tab flat in the notch and the loop taut: turning the motor shaft by hand spins the 80T with no slip or belt skip.

Source: Voron manual p.44 · Voron-2 CAD Voron_2.4r2_Assembly_STEP.zip @ de7e89d (cam throw)

Step 02.35 — Tighten the M5 bolts

What you're looking at: Manual p.45: the two M5×10 in the motor foot, the motor-end one and the drive-end one through the cam. They are tightened only now, with the cam closed, so the motor position the cam set is what gets locked in.

Parts: none.

Do: Only now, with the cam closed, tighten the two M5×10 in the motor foot; the drive-end one clamps the cam as well. Then confirm the two M5×40 in the drive body have not moved.

check Check

All four bolts tight. Nothing has moved. The belt is still correctly seated in both pulleys.

Source: Voron manual p.45 · Video: Part 2 @1:18:48

Step 02.36 — Fit the rubber foot

What you're looking at: Manual p.45: one of the printer's four rubber feet, bolted to the corner while the machine is still upside down and the underside is reachable. Its M5×16 threads into the nut captive in the blue baseplate.

Parts:

  • Rubber foot 38×19 mm ×1
  • M5×16 BHCS ×1

Do: With the printer still upside down, set a rubber foot on the baseplate at this corner and fix it with one M5×16 BHCS through the foot into the M5 nut you dropped into the baseplate at Step 02.25.

check Check

Foot square to the corner and firmly attached.

Helper: Holds the rubber foot square on the baseplate while you drive its screw.

Source: Voron manual p.45 · Video: Part 1 @3:34:45

Step 02.37 — Check the drive did not shift when the tensioner closed

What you're looking at: Manual p.46: a section through the finished corner. Closing the cam pushes the motor away from the drive body, and the reaction shoves the body. If it was not seated square when its M5×40 went tight it moves, and the section is how you tell.

Parts: none.

Do: Sight down the section view on the page and compare. The drive body must still sit hard against the corner and square to both extrusions.

check Check

No skew, no gap at the corner, belt still fully on both pulleys. If the drive moved, undo the bolts, realign, and redo Steps 02.34–02.35.

Source: Voron manual p.46

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

the Z0 corner is complete: drive body on its two M5×40, motor slid in, cam closed, both M5×10 tight, rubber foot on, and the p.46 section check passed. One corner is a self-contained unit and this is the natural stop.

Step 02.38 — Build and fit the other three Z drives

What you're looking at: Manual p.47: all four corners done. Two corners take the _a hand of every printed part, Z0 and Z2, and two take _b, Z1 and Z3. The cable labels go on now because in Ch 10 four identical black stepper cables arrive at the mainboard together.

Parts:

  • M5 roll-in T-nut ×12
  • M5×40 SHCS ×6
  • M5×10 BHCS ×6
  • M5×16 BHCS ×3
  • Rubber foot 38×19 mm ×3
  • [a]_belt_tensioner_a ×1
  • [a]_belt_tensioner_b ×2
  • reused: the other three closed drives
  • reused: the other three motor and mount assemblies

Do:

  1. Repeat Steps 02.29–02.37 at Z2 with the other _a set, then at Z1 and Z3 with the _b parts.
  2. Label each motor's cable Z0/Z1/Z2/Z3 by its physical corner.
  3. With a helper, turn the printer upright onto its feet.

check Check

Four drives, feet, tensioned belts, closed cams and labelled cables. Deck captured by its eight clips, the frame back upright on its feet without rocking.

Helper: Writes Z0 to Z3 on the motor cable labels by physical corner.

Source: Voron manual p.47 · LDO wiring guide § Connecting Steppers · Video: Part 2 @0:02:14

pause Good stopping point · ~55 min since the last one

since the last pause, in three ~18-min corners — Z1, Z2 and Z3 built and fitted the same way. Stop after any corner whose four M5 bolts are tight, tensioner closed and foot fitted; never with a cam open and the motor free to slide. All four cables labelled Z0–Z3 by physical corner, and the printer back upright on its feet.

Step 02.39 — Assemble a Z idler cage

What you're looking at: Manual p.48: the Z idler, the assembly at the top corner that turns the long Z belt back down. z_tensioner_bracket is the printed cage that bolts to the frame; the blue [a]_z_tensioner_9mm slides inside it on the screw you tension the Z belt with in Ch 06.

Parts:

  • z_tensioner_bracket_a ×2
  • z_tensioner_bracket_b ×2
  • [a]_z_tensioner_9mm ×4
  • M3×16 SHCS ×4
  • M3 hexnut ×4

Do: Build four cages, two _a and two _b. Drop an M3 hexnut into the bracket's pocket. Slide the blue tensioner in and run an M3×16 SHCS up through it into the nut. Leave it a couple of turns short of tight.

check Check

In all four, nut captive, screw engaged, tensioner sliding smoothly in the bracket with no side play.

tip Tip

In plan, print face down, the slider channel's open side toward you and the two oval slots left–right: tab on the left = _a, on the right = _b.

Source: Voron manual p.48 · Video: Part 2 @1:37:11

Step 02.40 — Fit the 20T idler on its M5×30 axle

What you're looking at: Manual p.48: a 20T idler dropped into the fork of the blue tensioner on an M5×30 screw used as its axle. An idler is a pulley that redirects a belt without driving it. See the glossary. It has to spin freely and stay in plane.

Parts:

  • GT2 20T 9 mm idler ×4
  • M5×30 BHCS ×4
  • reused: the four idler cages

Do: Drive an M5×30 BHCS through each slider's fork with a 20T 9 mm idler between the arms. It cuts its own thread in the Ø5 holes, so keep it square. Build all four, two a brackets and two b.

check Check

Idler spins freely on the axle with no axial slop, and its tooth band sits centred in the fork. Four idlers built.

Source: Voron manual p.48

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

four idler cages assembled with their captive M3 nuts and 20T idlers on M5×30 axles, tensioner screws left deliberately short of tight. Nothing is mounted to the frame yet.

Step 02.41 — Pre-load two M5 T-nuts at a top corner

What you're looking at: Manual p.49: two M5 T-nuts in the top side rail, the top extrusion running front to back, in its inner slot right beside the corner. They lie along the rail, where the idler bracket's two mounting holes land.

Parts:

  • M5 roll-in T-nut ×2

Do: Roll two M5 T-nuts into the inner slot of the top side rail above a Z drive, the top rail running front to back, right against the corner. Not into the vertical.

check Check

Two T-nuts in the top side rail's inner slot, right against the corner, free to slide.

Source: Voron manual p.49

Step 02.42 — Mount the idler, matching the drive below it

What you're looking at: Manual p.49: the idler bracket going onto the top corner. Its pulley and the 20T pulley in the drive below it have to lie in one vertical plane. A bracket not pressed hard into the corner leaves a twist in that plane.

Parts:

  • M5×30 BHCS ×2
  • reused: one idler of the drive's hand

Do: Offer the idler to the corner. Its pulley must face the same way as the pulley in the drive below it. Fit two M5×30 BHCS through it into the side-rail T-nuts, press the bracket firmly into the corner, then tighten.

check Check

Idler pulley and the drive's 20T below lie in one vertical plane. Bracket hard into the corner, its top flush with the top rails.

Helper: Sights down both pulleys and says if the belt line twists.

tip Tip

Sight down the two pulleys, or hang a length of 2GT belt between them and look for twist.

Source: Voron manual p.49

Step 02.43 — Fit the remaining three Z idlers

What you're looking at: Manual p.50: the other three idlers, two _a brackets and two _b. Each one is aligned to the drive underneath it, so all four Z belts run true.

Parts:

  • M5×30 BHCS ×6
  • M5 roll-in T-nut ×6
  • reused: the remaining three idlers

Do: Repeat Steps 02.41–02.42 at Z2 with the other _a bracket, then at Z1 and Z3 with the _b brackets. Each idler bolts into the top side rail's inner slot, above its drive.

check Check

Four idlers fitted, each one aligned with the drive beneath it, all pressed into their corners, all eight M5×30 tight.

Source: Voron manual p.50

Step 02.44 — Close the chapter

What you're looking at: Manual p.51 is a divider page with no assembly content: the marker that the Z chapter is finished. Look the work over now, because the gantry and the electronics bay are about to cover most of what you just built.

Parts: none.

Do: Use it as the marker that the Z chapter is done. The printer has been upright since Step 02.38. Work through Checkpoint 02 and make sure the measured deck thickness is in your build log.

check Check

Checkpoint 02 fully ticked.

Helper: Ticks the checkpoint list while you point at each item on the machine.

Source: Voron manual p.51

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

all four Z idlers mounted, each aligned with the drive below it, all eight M5×30 tight, printer back upright on its feet. Work through Checkpoint 02 before the gantry starts hiding this.

Checkpoint 02

  • All four Z rails run their full travel with no notch, tight spot or grinding; every carriage is taped or stoppered.
  • Rail surfaces are clean and dry and grease is inside the carriages only — carried over from Ch 00 Steps 00.18–00.21 and re-confirmed at Step 02.05.
  • All four rails are centred on their extrusions, each facing the rail on its own side of the machine (front-left ↔ rear-left, front-right ↔ rear-right), and share the same 3 mm bottom gap and the same nine-hole pattern (holes 2–18, no end holes).
  • Deck panel notch is at the back; panel sits inside the frame opening under the bed extrusions, held up by eight clip ledges, no rock; four M5 T-nuts aligned under the four deck holes and left unbolted for Ch 09 Step 09.5.
  • _a parts at Z0 and Z2, _b at Z1 and Z3 (or the reverse if the Step 02.29 dry-fit said so — written in the build log), and each idler the same hand as the drive below it.
  • Measured deck-panel thickness is written down and the fitted deck supports (8 off) match it.
  • Every 20T drive pulley sits 33 mm along its shaft; every 16T motor pulley sits 10.7 mm off the motor face.
  • All 24 M4×4 set screws are tight, threadlocked, and at least one per pulley lands on the shaft flat.
  • Four M5 precision spacers per drive (16 total) — spacers, not shims.
  • Each Z drive shaft turns freely by hand through the belt, with no belt skip and no bearing rumble.
  • All four tensioner cams are closed and no drive shifted when its cam closed (p.46 check).
  • Four rubber feet fitted; the printer stands on all four without rocking on the reference surface.
  • Each Z idler faces the same way as the pulley in the drive below it and is pressed hard into its corner.
  • Four motor cables labelled Z0 / Z1 / Z2 / Z3 by physical corner.
Revali passing a gate
You built four Z drives, four idlers, four rails and a clipped-in deck. 11 gummy worms.

Common mistakes

  • Bolting a rail on dry. Once a rail is on an extrusion you cannot use the flip-and-pack method, and a dry MGN9 wears out. Rails off again, or a compromised axis — check at Step 02.05 that Ch 00 really did all four (§5.2 W9).
  • Missing a heat-set insert before the drive is closed. Six M3×40 have to come out and the shaft assembly has to be lifted to reach it. Do the insert pass as a batch, count the pockets, and only then start assembling (§5.2 W3).
  • A 20T pulley on a Z motor. The 16T and 20T look nearly identical. The machine will home and move and be silently wrong on every Z dimension, because gear_ratio: 80:16 is baked into the config. Count teeth, then clear the 16T pulleys off the bench (p.38).
  • Skipping the deck supports "until the panels chapter". The deck cannot be lifted once the gantry and electronics are in — the frame has to come partly apart. LDO puts this at p.29–30 for a reason (§5.2 W4).
  • Tightening rail screws from one end. The rail bows and the carriage develops a tight spot that no amount of greasing fixes. Always centre-outward (p.24).
  • Set screws finger-tight or off the flat. They loosen under Z load, the belt slips, and the gantry drops out of level. Threadlocker on all of them, one on the flat, tightened with a proper hex driver (p.32, §5.2 W12).
  • Closing a drive with the halves upside down. Screws started from above into the retainer's visible brass inserts thread only into that insert, clamp nothing, and pull the insert out of its boss. The M3×40 heads sink into the main's counterbores; the retainer's inserts are at the bottom of the stack (Step 02.24).
  • The wrong hand at a corner. It bolts on fine and shows up in Ch 06 when the 20T is not under its idler. Diagonals share a hand (Step 02.02); dry-fit the first unit (Step 02.29).
  • M5×40 through the motor foot. The foot's holes are 9 mm deep M5×10 holes; a 40 mm screw bottoms in the slot and jacks the T-nut. The long screws go down the drive body's wells (Step 02.31); the motor foot takes the two M5×10, both left loose until the cam is closed (Steps 02.32–02.33).
  • Cam at the wrong end of the foot. The tensioner lives under the drive end of the motor foot, on the drive-end screw; at the motor end it has nothing to push against and the loop never comes taut (p.43, Step 02.33).
  • Bolting the deck down here. The four M5×10 go in with the DIN rails in Ch 09 Step 09.5. Fitting them now means undoing them again — and it double-counts the same four bolts in two chapters' hardware totals.

Next

Chapter 03 — Build plate: bed, magnet sheet, spacers and the M3×20 mounting screws (manual p.52–61, with LDO's p.55/56 skips).