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

Time: 4.25–6.25 h hands-on, first build · Sessions: 11 × ~30 min · Steps: 44

Start the chapter · Resume · Read the whole chapter on one page

Before — end of Ch 01: the squared frame

After — end of Ch 02: Z drives, idlers, rails and deck

What this chapter builds — orange is new, grey is what you already built. The four Z drive units under the frame, the four idler cages above them, the Z rails and carriages on the verticals, and the deck panel. CAD rails are MGN9 300 mm; your 350 kit uses 400 mm rails, and the deck panel is the 350 one.

StartBefore you start

Step 02.01Lay out and label the chapter's printed partswith a helper

Step 02.02Learn the four Z positions before you build anythingwith a helper

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

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

Step 02.05Confirm the four Z rails are already cleaned and greasedwith a helper

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

Step 02.07Tighten from the centre outward

Step 02.08Secure the carriage before the printer is turned over

Step 02.09Install the remaining three Z railswith a helper

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

Step 02.11Turn the printer upside down and pre-load the deck T-nutswith a helper

Step 02.12Caliper the deck panel and choose the support thicknesswith a helper

Step 02.13Drop the deck panel in, notch to the backwith a helper

Step 02.14Fit the deck support clips

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

Step 02.16Fix the printer's orientation in your headwith a helper

Step 02.17Fit the 20T pulley to the 5×60 shaft, 33 mm outwith a helper

Step 02.18Verify the pulley at 33 mm, then repeat ×4with a helper

Step 02.19Build the bearing/pulley stack on each shaft

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

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

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

Step 02.23Check the shaft position against the section viewwith a helper

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

Step 02.25Fit the blue baseplate and its captive M5 nut

Step 02.26Confirm the belt loop is captured

Step 02.27Fit the 16T pulley to a Z motor at 10.7 mmwith a helper

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

Step 02.29Identify Z0 and start there

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

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

Step 02.32Slide the motor assembly in at an angle

Step 02.33Fit the blue belt tensioner, still loose

Step 02.34Flip the tensioner latch closed

Step 02.35Tighten the M5 bolts

Step 02.36Fit the rubber footwith a helper

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

Step 02.38Build and fit the other three Z driveswith a helper

Step 02.39Assemble a Z idler cage

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

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

Step 02.42Mount the idler, matching the drive below itwith a helper

Step 02.43Fit the remaining three Z idlers

Step 02.44Close the chapterwith a helper

Checkpoint 02Tick before moving on

Gather per session — what to lay out before each bench segment.

• Steps 02.01–02.04 · ~40 min — Fasteners, Tools & Misc box: M3×5×4 brass heat-set insert ×36 · Printed parts: z_drive_retainer_a ×2 (bin 02-Z0, 02-Z2); z_drive_main_a ×2 (bin 02-Z0, 02-Z2); z_drive_retainer_b ×2 (bin 02-Z1, 02-Z3); z_drive_main_b ×2 (bin 02-Z1, 02-Z3) · Tools and consumables: soldering iron with the LDO brass tip · Set out for later steps: all Chapter 02 printed parts from batches B00, B01 and B02 · Already on the bench: the Gate B retainer with its first insert
• Steps 02.05–02.08 · ~25 min — Fasteners, Tools & Misc box: M3×8 SHCS ×9; M3 roll-in T-nut ×9 · Linear Rail Kit box: MGN9H 400 mm rail ×1 · Printed parts: MGN9_rail_guide_x2 jigs ×2 (bin 00-jigs) · Tools and consumables: 3 mm hex key as the gap feeler; masking tape, or the rail's plastic shipping stoppers · Set out for later steps: MGN9H 400 mm rail ×3, labelled Z0–Z3 · Already on the bench: the first Z rail and its nine started screws
• Steps 02.09–02.10 · ~35 min — Fasteners, Tools & Misc box: M3×8 SHCS ×27; M3 roll-in T-nut ×27 · Linear Rail Kit box: MGN9H 400 mm rails ×3 · Printed parts: z_rail_stop_x4 ×4 (bin 02-Z0, 02-Z1, 02-Z2, 02-Z3)
• Steps 02.11–02.16 · ~30 min — Fasteners, Tools & Misc box: M5 roll-in T-nut ×4 · Panel Kit box (carton 2): deck panel ×1 · Printed parts: deck_support_3mm_x8 ×8 (bin 02-deck) · Tools and consumables: caliper · Set out for later steps: deck_support_4mm_x8 ×8, only if the panel measures 4 mm · Already on the bench: the four deck T-nuts
• Steps 02.17–02.21 · ~35 min — Motion box: 5×60 mm shaft ×4; GT2 20T 9 mm pulley ×4; 625-2RS bearings ×12; GT2 80T pulley ×4 · Fasteners, Tools & Misc box: M4×4 set screws (pre-threadlocked) ×16; M5 precision spacer 1 mm ×16 · Belts, Chains & Fans box: Gates 2GT closed loop 6 mm × 188 mm ×4 · Tools and consumables: caliper · Already on the bench: the four shafts with their 20T pulleys
• Steps 02.22–02.26 · ~35 min — Fasteners, Tools & Misc box: M3×40 SHCS ×24; M5 hexnut ×4; M3×8 SHCS ×12 · Printed parts: [a]_z_drive_baseplate_a ×2 (bin 02-Z0, 02-Z2); [a]_z_drive_baseplate_b ×2 (bin 02-Z1, 02-Z3) · Already on the bench: one z_drive_retainer_a with its inserts (bin 02-Z0, 02-Z2); one belted shaft assembly; one z_drive_main_a with its side inserts (bin 02-Z0, 02-Z2); the other three retainers and mains; the other three belted shaft assemblies
• Steps 02.27–02.28 · ~25 min — Motion box: GT2 16T pulley ×4 · Fasteners, Tools & Misc box: M4×4 set screws ×8; M3×8 SHCS ×12 · Motor Kit box: NEMA17 Z motor LDO-42STH48-2004AC ×4 · Printed parts: z_motor_mount_a ×2 (bin 02-Z0, 02-Z2); z_motor_mount_b ×2 (bin 02-Z1, 02-Z3) · Already on the bench: the four Z motors with their 16T pulleys
• Steps 02.29–02.37 · ~30 min — Fasteners, Tools & Misc box: M5 roll-in T-nut ×4; M5×40 SHCS ×2; M5×10 BHCS ×2; M5×16 BHCS ×1 · Belts, Chains & Fans box: Rubber foot 38×19 mm ×1 · Printed parts: [a]_belt_tensioner_a ×1 (bin 02-Z0, 02-Z2) · Already on the bench: one complete _a drive; one _a motor and mount assembly; the completed _a drive; the _a motor and mount assembly
• Step 02.38 · ~55 min — Fasteners, Tools & Misc box: M5 roll-in T-nut ×12; M5×40 SHCS ×6; M5×10 BHCS ×6; M5×16 BHCS ×3 · Belts, Chains & Fans box: Rubber foot 38×19 mm ×3 · Printed parts: [a]_belt_tensioner_a ×1 (bin 02-Z0, 02-Z2); [a]_belt_tensioner_b ×2 (bin 02-Z1, 02-Z3) · Already on the bench: the other three closed drives; the other three motor and mount assemblies
• Steps 02.39–02.40 · ~20 min — Motion box: GT2 20T 9 mm idler ×4 · Fasteners, Tools & Misc box: M3×16 SHCS ×4; M3 hexnut ×4; M5×30 BHCS ×4 · Printed parts: z_tensioner_bracket_a ×2 (bin 02-Z0, 02-Z2); [a]_z_tensioner_9mm ×4 (bin 02-Z0, 02-Z1, 02-Z2, 02-Z3); z_tensioner_bracket_b ×2 (bin 02-Z1, 02-Z3) · Already on the bench: the four idler cages
• Steps 02.41–02.44 · ~25 min — Fasteners, Tools & Misc box: M5 roll-in T-nut ×8; M5×30 BHCS ×8 · Already on the bench: one idler of the drive's hand; the remaining three idlers

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