sandTable/print/README.md

Print files

Latest: v3. The v3/ folder now holds every printed part, including the ones that didn't change. The "Full parts list (v3)" table below has quantities and print notes.

Folder	What
v3/	The complete v3 set: every printed part. New shell, deck, center plate, hub and slip-ring parts, seam plates and plugs, and a counterweight for the arm, plus copies of the unchanged parts (14–25). The rail bolts straight to the hub again (no 29c). Print 00b-fit-test-6804 first. See "What changed in v3".
v2-current/	The full v2 set, numbered in print order. Parts not replaced in a later folder still come from here.
v2.7-removable-arm/	Replaced by v3. In v3 the rail bolts straight to the hub, so neither 29b nor 29c is used. 30 and 13 are copied into v3/ unchanged.
v2.6-idler-sleeve/	16-idler-sleeve-wide.stl: replaces v2-current/16. The belt groove is 7 mm instead of 6, so the belt no longer rubs both rims.
v2.5-switch-pegs/	14-switch-mount-pegs.stl: the v2.1 switch mount with 2 pegs instead of M2 screw holes. The switch slides onto the pegs and is glued. Use it instead of the v2.1 mount if you have no M2 screws.
v2.4-hub-adapter/	Replaced by v2.7; don't print 29. Still print 18-magnet-cup-short.stl.
v2.3-uno-plate/	Only for a v1-original deck Q1. Not needed with the v3 deck.
v2.2-slip-ring-fix/	Replaced by v3 (new 26 coupler and 27 holder for the bigger hub).
v2.1-switch-update/	Also print these 2. A new switch mount (it replaces v2-current/14) and a striker you glue onto the carriage.
v1-original/	The first export, kept for reference. Don't print its 05-deck-Q1-arduino.stl.

Full parts list (v3)

Part	Folder	Notes
00 fit test 608	v3	Print first. Pins and pockets for the 608 bearings (carriage rollers, idler). The parts use the 8.1 mm pin and 22.2 mm pocket.
00b fit test 6804	v3	Print first. Checks the hub bearing fits (below).
01–04 shell Q1–Q4	v3	Upright, as before. The deck bosses have a 45° underside, so no supports.
05–08 deck Q1–Q4	v3	Upside down, as before. Deck Q1 has the correct Uno standoffs, so 28 isn't needed.
09 center plate	v3	Upside down, as before.
10 hub 80T pulley	v3	10-hub-80T-pulley-bolted.stl. PETG, arm plate on the bed, as before. The rail bolts to it with 2× M5×12 from underneath.
11 hub clamp collar	v3	Flat as modeled (the thin ring on top). Replaces the glued slip-ring adapter.
13 arm motor bracket (tall window)	v3	Copy of v2.7/13. Tree supports.
14 switch mount	v3	Print one: 14-switch-mount-pegs (switch glued on 2 pegs) or 14-switch-mount-M2 (2× M2 screws). Unchanged from v2.5 / v2.1.
15 idler bracket	v3	Unchanged from v2-current.
16 idler sleeve (wide)	v3	Unchanged from v2.6.
17 carriage	v3	Unchanged from v2-current.
18 magnet cup (short)	v3	Unchanged from v2.4.
19 roller washers, 19b idler washer, 20 magnet spacers	v3	Unchanged from v2-current. The washer file has all 4 washers; the spacer file has all 3 spacers.
21–24 sand ring	v3	16 mm tall, unchanged from v2-current. Floor raised on 3.5 mm rubber stoppers? Print the -12.5mm files instead, so the glass still sits inside the rim.
25 carriage striker	v3	Unchanged from v2.1.
26 slip-ring coupler	v3	Bigger, to peg into the collar.
27 slip-ring holder	v3	Screws to the post now.
30 motor bracket shim	v3	Copy of v2.7/30.
31 seam plate low ×4, 32 seam plate high ×4	v3	Flat as modeled, nut slots on top.
33 seam plug ×16	v3	Flat.
34 counterweight	v3	Flat, pockets up, no supports. Use 100% infill (or as high as you like): its own weight counts.
35 counterweight lid	v3	Flat.
36 Uno turnaround plate	v3	Print this. Turns the Uno around so its USB faces the centre; on the v3 deck it faced the wall with no room for the plug. Flat face on the bed, standoffs up, no supports. See below.
12 stator collar, 28 Uno adapter plate, 29, 29b, 29c	—	Not used in v3.

What changed in v3 (rebuild fixes)

Picture: docs/v3-changes.png.

0. Uno turned around (part 36, added 2026-11-01)

• Problem: the v3 deck's standoffs hold the Uno with its USB jack pointing at the wall. The jack ends 2.4 mm from the wall, so a USB plug can't go in.
• Fix: 36-uno-turnaround-plate.stl, a 3.4 mm plate the size of the Uno (plus 2.5 mm all round), built like part 28:
  • It screws to the deck's 4 Uno standoffs with 4× M3×6 button heads, sitting flush in counterbores (the 4 that held part 28 are the right ones; socket heads would stick out 1 mm).
  • Its own 4 standoffs (3.1 mm) hold the Uno turned half a turn, so the USB jack faces the centre. The Uno's own 4× M3×6 screw into them.
  • Both hole patterns are lopsided, so the plate fits the deck only one way, and the Uno fits the plate only one way.
  • The Uno sits 6.5 mm lower than before, the same as it did on part 28.
• Room for the plug: the jack now ends 70 mm from the centre, and a USB-B plug reaches to about 37 mm. That leaves 10 mm to the slip-ring holder and 16 mm to the collar's screw lug. Run the cable down and round the side of the board to the notch in the wall.
• 12 V: the shield's power terminal turns to face the centre too, so the supply wires need about 7 cm more length inside the table.
• Checked in the model: no clashes with the deck, center plate, hub, collar, slip ring and holder, spin motor or seam plates. The plate's corners stay 3.5 mm inside the wall and clear of the deck bosses.
• Printing: flat face on the bed (the STL is already turned that way), standoffs up, no supports. PLA or PETG.

1. Deck screws you can reach

• Problem: the 8 deck-to-shell screws were 150 mm from the center, under the floor ledge, which reaches in to 143 mm. A screwdriver couldn't get a straight line to them.
• Fix: each shell quarter has 2 new bosses under the deck. Each has a 45° underside, so it prints upright without supports.
  • The screws now sit 137 mm from the center, 6 mm inside the ledge's tip, so a screwdriver goes straight down.
  • The deck holes moved to match.
  • Use M3×12 button heads; the pilot holes are 8 mm deep.

2. Seam joints from the outside

• Problem: the old joint blocks were bolted sideways, only 4 mm from the wall, so a driver couldn't reach them.
• Fix: the screws go straight through the wall from outside into a plate on the inside.
  • Each seam gets a low plate (31, below the deck) and a high plate (32, above the deck), with 4 screws per seam.
  • Drop an M3 nut into each plate's slot from the top, hold the plate against the inside of the wall, and drive M3×8 button heads from outside.
  • Each screw head sits in a 6.2 mm counterbore. A plug (33) presses in flush on top to hide it.
• Clearance: the high plates stay clear of the arm (in the model). The idler bracket and sleeve pass underneath (below 79 mm high), the carriage plate passes 2 mm above, and the rail tip and rollers stay at least 4 mm inside the plates' inner face.
• Modeling note: the shell quarters are now built as four separate 90° pieces instead of one ring split in four. The exported meshes were checked and repaired, so the walls are true to within 0.02 mm.

3. Arm bolted straight to the hub, at both ends

Picture: docs/arm-bolted-counterweight.png.

• Problem: with 29b/29c, the mount was glued to the hub and the rail was held by 2 side bolts at the motor end only. The far half of the rail just sat on the hub, and the glued wall carried the motor's weight, so the arm could flex. (29b's wall also hit the spin motor's shaft tip; 29c was the fix for that.)
• Fix: no hub mount at all. The rail bolts straight down onto the hub with 2× M5×12 socket heads, 17 mm each side of the center, into T-nuts in the rail's bottom slot. That's how the very first build was done.
  • The bolts go in from under the hub, in counterbores in the pulley. The heads end up under the hub, so the arm and hub are bolted together on the bench and go into the table as one piece.
  • That's fine now because the v3 hub lifts out: undo the collar (one screw) and the arm and hub come out together. See the assembly order below.
  • The hub's arm plate is 1 mm thicker (top at 74 mm, where 29c's strip was), so every height stays the same. Keep the 1 mm shim (30) under the motor bracket and the short magnet cup.
  • The wire groove across the top of the hub is bigger (6 mm wide, 4.5 mm deep) and goes on the wire side, opposite the belt.
  • No glue anywhere in the arm or hub.
• Clearances checked in the model: the hub plate and bolt heads clear the spin belt, the spin motor's pulley and shaft tip at every angle, and the carriage at every position.

4. Connectors through the hub

• Problem: the hub shaft was 8 mm (sized for the 608 bearings) with a 4.5 mm hole, so only bare wires fit.
• Fix: the hub turns on 2× 6804 bearings (20 × 32 × 7 mm) instead of the 608s. They're the same thickness, so every height stays the same.
  • Shaft: now 20 mm, with a 15 mm hole. A 4-pin JST-XH, a 6-pin JST-PH or a Dupont 1×4 housing fits through, one connector at a time.
  • Where the plugs meet (changed with the bolted arm): the arm's own wires go down through the hub on the bench, and the slip ring's wires plug into them under the hub. The joined plugs then push up inside the hub's 15 mm hole, out of the way. Nothing is soldered or crimped in the table.
  • Plugs: Dupont 2.54 mm is easiest (female on one side, male on the other): a 4-pin pair for the arm motor and a 2-pin pair for the switch. If the motor cable already ends in a 4-pin female plug, crimp male pins in a 1×4 housing onto the slip ring's 4 motor wires. Two joined Dupont pairs fit side by side in the hole.
  • Clamp collar (11): replaces the glued slip-ring adapter. It holds the hub down with one M3 pinch screw, so the hub can be taken out again.
  • Coupler (26): bigger, so its 3 pegs reach into the collar. It still glues to the slip ring's spinning center, and its side slot lets the wires slip in sideways.
  • Holder (27): screws to its post with an M3×16 instead of being glued. The post moved out 8 mm, clear of the collar.
• Fit test first: print 00b-fit-test-6804.
  • Pockets (32.0 / 32.2 / 32.4, left to right): the bearing should press in with a snug push. The center plate uses 32.2.
  • Stubs (19.9 / 20.0 / 20.1 / 20.2): the bearing should go on with a firm push and not fall off. The hub uses 20.1.
  • If another size fits better, tell me which. The center plate and hub re-export from brg2_d and shaft2_d.
• Clearances checked in the model:
  • The pinch-screw lug reaches 21.1 mm from the center as it turns; the holder post starts at 23.5 mm.
  • The spin motor body sits 4.9 mm from the bigger bearing housing, or 1.9 mm with its slots pushed all the way in.

5. Counterweight

• Problem: the arm motor hangs off the back end, so the arm is heavy on that side. With the carriage halfway out, it's about 7 kg·mm out of balance (roughly 70 g sitting 100 mm out on the far side would fix it).
• Fix: a printed counterweight box (34) bolts under the far half of the rail with 2× M5×10 into T-nuts in the bottom slot, 66 and 102 mm from the hub center.
  • Its 2 round pockets sit beside the rail on the wire side (opposite the belt). Each takes a stack of up to 8 US quarters (24.3 mm); steel nuts, washers or fishing weights also work.
  • A lid (35) closes the pockets with 3× M3×8 button heads on the outer edge.
  • How many quarters: start with 7 in the outer pocket (the one nearer the tip; it counts more). Then balance the arm on a pencil (assembly step 4 below) and add or remove quarters until it sits level. The motor's real weight is the main unknown, so trust the pencil over the count.
  • It's balanced with the carriage halfway out. At either end of its travel the arm is now about 5 kg·mm off balance, compared with 12 before.
• Clearances checked in the model: it stays under the carriage's rollers and roller-washer screws (1.3 mm below the screw heads), clear of the carriage's belt clamp and the arm belt (it doesn't go past the rail's belt-side face), and clear of the idler bracket. As the arm turns, it passes over the center-plate screw heads with 1.8 mm to spare and stays outside the spin motor's pulley.

Assembly order (center)

Build the shell and deck first (next section), then:

1. Bearings: press one 6804 into each pocket of the center plate, from the top and from the bottom, until each sits on the lip between them.
2. Spin motor: hang it under the center plate with its 20T pulley, screws loose and the motor slid toward the center so the belt will go on easily.
3. Arm, on the bench:
   • Motor bracket with the 1 mm shim under it (2× M5), arm motor and pulley, switch mount and switch.
   • Carriage, slid on from the tip end, then the idler bracket, bearing, sleeve and washer, then the arm belt.
   • Drop T-nuts into the rail's bottom slot: 2 for the hub at 63 and 97 mm from the rail's back end (17 mm each side of the hub center, which is 80 mm from the back end), and 2 for the counterweight at 146 and 182 mm.
   • Counterweight (34) under the far half with 2× M5×10, pockets on the wire side.
4. Balance: push the carriage to the middle of its travel (magnet about 66 mm past the hub center). Lay the rail across a round pencil at the hub center (80 mm from the back end) and add quarters to the outer pocket until it sits level. Then screw on the lid (3× M3×8).
5. Wires down through the hub: run the arm motor cable and the switch wires (with their plugs on) along the rail's wire-side slot to the middle. Lay them in the hub's top groove and feed the plugs down through the hub's hole, so they hang out of the bottom of the shaft.
6. Hub onto the rail: set the hub on the rail's bottom face, groove on the wire side, holes over the 2 T-nuts. Bolt it with 2× M5×12 socket heads from under the hub.
7. Spin belt: slip the 200 mm belt over the bottom of the hub shaft and onto the hub pulley.
8. Arm into the table: lower the hub shaft through both bearings, hooking the belt around the spin motor's pulley on the way down. The shoulder rests on the top bearing's inner ring, and the plugs hang out under the center plate.
9. Collar: from below, slide it over the hanging plugs and onto the shaft bottom, thin ring up against the lower bearing, peg holes facing down. Tighten the pinch screw (M3×12 or ×16) until it grips.
10. Belt tension: slide the spin motor out until the belt is snug and tighten its 4 screws from above (swing the arm aside).
11. Plug in: plug the slip ring's top-wire plugs into the arm's plugs, then push the joined plugs up into the hub's hole.
12. Coupler: slide its side slot over the top wires. Glue its socket onto the slip ring's spinning center (gel CA on the socket wall only).
13. Holder:
    • Set the slip ring's body in the holder: flange on the disc, peg in a flange hole.
    • Slide the holder's sleeve up onto the post. Turn the arm so the coupler's 3 pegs go into the collar's 3 holes.
    • Fix it with an M3×16 through the sleeve into the post.

Taking the arm out later:

1. Holder screw out, then lower the slip ring and coupler off the collar's pegs.
2. Pull the joined plugs down out of the hub and unplug them.
3. Turn the arm until the collar's pinch screw faces you and loosen it.
4. Loosen the spin motor's 4 screws and slide it in to slacken the belt.
5. Lift the arm and hub straight up. The belt comes with the hub.
6. On the bench, the 2 hub bolts and 2 counterweight bolts undo from below.

Assembly order (shell and deck)

1. Stand the 4 shell quarters in a ring.
2. At each seam, fit a high plate (above the deck line) and a low plate (below it) against the inside, with nuts in their slots. Drive 4× M3×8 button heads from outside, then press in the plugs.
   • The low plates can also go in later from underneath, since the bottom is open.
3. Set the deck quarters on the ledge and bosses, and fix them with 8× M3×12 button heads straight down through the deck.
4. Screw the center plate to the deck (8× M3×8), as before.

Hardware changes

• Buy: 2× 6804-2RS bearings (20 × 32 × 7 mm, also sold as 61804). The two hub 608s become spares.
• Deck to shell: 8× M3×12 button heads instead of M3×8.
• Seams: 16× M3×8 button heads and 16× M3 hex nuts. The 8× M3×16 + nuts from the old joints are no longer used.
• Collar: 1× M3×12 or M3×16. Holder: 1× M3×16. Two of the old seam-joint M3×16s work for both.
• Arm to hub: 2× M5×12 socket heads (M5×13 also works) and 2 T-nuts. The 2× M5×10 from 29b move to the counterweight.
• Counterweight: 2× M5×10 and 2 T-nuts, 3× M3×8 button heads for the lid, and about 7 US quarters (or steel nuts or washers).
• Plugs: a 4-pin and a 2-pin Dupont 2.54 mm pair (male and female housings and pins).

What changed in v2.7 (removable arm)

Replaced in v3: the rail now bolts straight to the hub, so 29b (and 29c) aren't used. The shim 30 and the tall-window bracket 13 still are.

• Why:
  • With v2.4/29, the strip is glued to the hub. The bolts holding the rail to it go in from below, where they can't be reached once the hub is in.
  • That made the arm permanent. The 1 mm strip was also the only link between rail and hub outside the hub plate, so it could flex.
• Why not bolts at all 4 corners:
  • The carriage runs over almost the whole rail, and its rollers hang down to 2.5 mm above the side slot.
  • The belt and belt clamp run 1 mm from the belt side of the rail.
  • The only place a side bolt can go is the motor end, behind where the carriage stops at home.
• 29b-hub-rail-mount.stl:
  • Strip and pegs: the same 1 mm strip over the hub plate, with the same 2 pegs into the hub's M5 holes.
  • Wall: 4 mm thick, along the rail's wire side (away from the belt), from the hub to 2 mm short of the rail's back end.
    • It stays 1 mm under the carriage's rollers along their path.
    • At the motor end, where the carriage never reaches, it is taller and has 2 bolt holes.
  • Glue (to the hub only):
    • the pegs
    • the strip on the hub plate
    • the wall's bottom edge on the hub pulley's top rim
    • the wall's inner face against the hub plate's side
  • Bolts: 2× M5×10 (button or socket head) go sideways through the wall into drop-in T-nuts in the rail's wire-side slot.
  • Wires: a notch lines up with the hub's wire groove. A 3 × 2 mm groove along the wall's outer face carries the slip-ring wires to the motor end.
  • Printing: the STL is already turned so the wall's outer face is on the bed. Tree supports go only under the 2 pegs. PETG.
• 30-motor-bracket-shim.stl:
  • A 1 mm plate between the motor bracket and the rail, with 2 holes for the bracket's M5s.
  • It replaces the end of the old strip, so all heights stay the same: short magnet cup, motor pulley 1 mm higher.
  • With it, M5×10 works on the motor bracket without washers.
• 13-arm-motor-bracket-SUPPORTS-tall-window.stl:
  • The belt window in the bracket is 2 mm taller, now 10 mm. Since v2.4 raised the arm (and the belt) by 1 mm, the belt rubbed the top of the old window by 0.5 mm. That rub is likely part of the stiffness you felt in the belt.
  • Otherwise the same as v2-current/13. Print it the same way: motor plate on the bed, tree supports.
  • Not reprinting it? File the window's top edge up 1–2 mm instead.
• Checked in the model:
  • The carriage, rollers and roller washers clear the new wall at home, over the hub, and every step in between.
  • Nothing new clashes with the hub, rail, motor bracket, switch mount, spin pulley or belts.
• Assembly order:
  1. At the hub, before gluing:
     • Slide the spin belt over the hub's arm plate and down onto the hub pulley.
     • Feed the slip ring's top wires up the shaft and lay them in the groove on top of the hub.
  2. Glue the mount onto the hub:
     • Pegs into the 2 holes, with the wall on the side where the groove opens.
     • The wires go out through the wall's notch, then into the groove on its outer face.
     • Let it cure.
  3. On the bench:
     • Motor bracket with the shim between it and the rail (2× M5), then the arm motor and pulley.
     • The carriage, slid on from the tip end.
     • The idler bracket, bearing, sleeve and washer, then the belt.
     • Drop 2 T-nuts into the wire-side slot at the motor end, about 8 and 18 mm from the rail's end.
  4. Set the arm on the mount:
     • The rail sits on the strip with its wire-side face against the wall, and the rail's back end 2 mm past the wall's end.
     • Line up the T-nuts with the wall's holes and fit 2× M5×10.
  5. After:
     • Wires along the groove to the motor end, then up to the switch and the motor.
     • Spin motor (screws on top of the center plate; swing the arm aside).
     • Switch mount and switch, short magnet cup with the 3 mm spacer, striker.
• To take the arm off later: undo the 2 side bolts, unplug the motor and switch, and lift the arm straight up. The motor, carriage and idler come with it. The mount stays on the hub.
• Not removable: the spin belt. It's trapped under the mount, as it was with v2.4.
• Picture: docs/removable-arm-mount.png.

What changed in v2.6 (wider idler groove)

• Why: the old sleeve's groove between its two rims was exactly 6.0 mm, the same as the 6 mm belt, so the belt dragged on both rims.
• 16-idler-sleeve-wide.stl:
  • The groove is now 7 mm, with 0.5 mm spare above and below the belt, still lined up with the motor pulley.
  • A 0.5 mm ledge inside the bottom sets the bearing height. It touches only the bearing's outer ring.
  • The rims are the same size (Ø29), and the bearing pocket is still brg_d (22.2).
• Fitting: push the 608 out of the old sleeve. Press it into the new one from the top, the side with the thicker rim, until it sits on the ledge. The thin rim goes down, toward the bracket, 0.5 mm above it.
• Printing: flat as modeled, thin rim on the bed.

What changed in v2.5 (switch mount with pegs)

• Why: no M2 screws on hand.
• 14-switch-mount-pegs.stl: the same as the v2.1 mount, but the 2 M2 holes are now 2 pegs, Ø2 mm and 5.5 mm tall, with pointed tips. They sit at the same spots, 9.5 mm apart.
  • KW12 mounting holes are about Ø2.2–2.3 mm, so the switch slides on with a little play.
  • The pegs are 1 mm shorter than the switch is thick, so they don't stick out the top.
• Fitting: slide the switch onto the pegs, lever facing the carriage, pressed flat on the plate. Put a drop of CA on each peg where it comes through, plus a thin line along the switch's bottom edge. Keep glue away from the lever hinge.
• Printing: flat, pegs up. Print the pegs slowly, or with "slow down for small layers" on, so they come out round.
• Diagram: docs/switch-mount-pegs.png.

What changed in v2.4 (hub-to-rail adapter)

Replaced by v2.7. Use 29b and its assembly order instead. The short magnet cup below still applies.

• Why: the hub's 2 rail bolts go in from underneath, so they can't be reached once the hub is in the center plate. The same goes for the idler and motor bracket bolts and the arm motor's screws.
• 29-hub-rail-adapter.stl: a 1 mm strip under the rail, 146 mm long.
  • Hub end: 2 pegs glue into the hub's M5 holes, plus glue on the arm-plate face.
  • Idler end: an M5×8 bolt goes into a T-nut, beyond the spin pulley's reach.
  • Motor end: the arm motor bracket's own 2 bolts pass through it.
  • Printing: flat, top face down, pegs up.
• 18-magnet-cup-short.stl: 1 mm shorter than v2-current/18, because the arm now sits 1 mm higher. Use only the 3 mm magnet spacer.
• Assembly order (checked against the model):
  1. Before gluing, at the hub:
     • Slide the 200 mm spin belt over the top of the hub's arm plate and down onto the hub pulley.
     • Feed the slip ring's top wires up the shaft and lay them in the groove on top of the hub, out its side.
  2. On the bench:
     • Bolt the strip (its motor end flush with the rail's back end) and the motor bracket to the rail; the bracket's 2 M5s go through the strip.
     • Fit the arm motor (4× M3×6) with its pulley 1 mm higher than usual.
     • Slide the carriage on from the tip end before the idler bracket; its belt-clamp tab can't pass the bracket base or the sleeve.
     • Fit the idler bracket (2× M5×12), then the bearing, sleeve and washer.
     • Put in the strip's idler-side M5×8.
     • Loop the belt around both pulleys and clamp it in the carriage.
  3. Glue the arm onto the hub. The pegs go in the hub's M5 holes. Turn it so the hub groove's opening faces the rail's wire side, away from the belt.
  4. Afterwards:
     • Route the wires up into the side slot.
     • The spin motor goes on from below; its screws are on top of the center plate, so swing the arm aside.
     • Fit the switch mount and switch (from the top), the short magnet cup with the 3 mm spacer, and the striker.
• Diagram: docs/hub-rail-adapter.png.

What changed in v2.3 (Uno adapter plate)

• Why: the v1-original deck Q1 has the Uno hole pattern flipped across the board. In the Uno's normal orientation, two of the holes land 1.3 mm from old standoffs.
• The fix: 28-uno-adapter-plate.stl turns the Uno 90° and shifts it so every Uno hole is at least 8.5 mm from every old standoff. No glue is needed.
• The plate: 3.4 mm thick.
  • Old standoffs: it screws to all 4 with M3×6 button heads, which sit flush in Ø6.4 × 1.9 mm counterbores.
  • Uno: 4 standoffs, 3 mm tall, take the Uno with M3×6.
• Fit: the Uno sits 6.4 mm lower than first designed, and its USB end now faces sideways. It still clears the shell bottom and the wall.
• Printing: flat, standoffs up. docs/uno-adapter-plate.png shows the layout.

What changed in v2.2 (slip ring)

• The fault: on the Comidox ring, the flange and body are one fixed housing; only the center boss around the top wires turns. Screwing the flange to the adapter locked the hub.
• The coupler: 26-slip-ring-coupler.stl is a Ø22 × 2.5 mm disc.
  • Top: 3 pegs push into the adapter's 3 old screw holes, with a drop of CA.
  • Bottom: a Ø5.3 × 1 mm socket takes the boss, with a small dab of gel CA on the socket wall only.
  • Gap: the boss bottoms in the socket, which leaves the flange 0.5 mm clear.
  • Slot: a side slot lets it slide onto the wires without unthreading them.
• The holder: 27-slip-ring-holder.stl replaces the stator collar, which only stopped rotation and let the body flop.
  • Fit: its cup goes around the slip-ring body and its block slides over the end of the fork tower. The block butting the tower's end sets the height.
  • Stopping rotation: the flange rests on the cup's top face, and a Ø2.6 peg sits in one Ø3.2 flange hole.
  • Glue: only the block to the tower. Leave the slip ring loose in the cup; the small play keeps its internal bearings from binding.
  • Printing: print it as modeled, block end down.
• Flange: not screwed down.
• Printing: print it flat with the pegs up, in PLA or PETG.
• Before printing: check the boss is about Ø5 mm and sticks out about 1.5 mm.

What changed in v2.1 (home switch)

• Switch mount: in v2-current, the switch sat with its lever running along the arm, so the carriage pushed the lever end-on and could bend or jam it. 14-switch-mount.stl turns the KW12 switch 90°, so its lever faces the carriage. The two M2 holes are 9.5 mm apart, side by side across the arm, 8.1 mm from the switch end of the mount.
• Lever edge: the switch's lever edge sits 0.5 mm behind the end of the mount, so the carriage stops against the plastic mount, not the switch.
• Striker: 25-carriage-striker.stl is a 5 × 18 × 4.5 mm block. Glue it (CA) on top of the carriage, against its back edge (the edge that faces the arm motor), centered side to side, with its back face flush with the carriage edge. It presses the lever along its full height.
• Switch to use: KW12 with a straight hinged lever (KW12-B, ideally the 1.1" lever), not the roller.
• Not printed yet? If you'd rather not reprint the mount, drill two 1.7 mm holes in the old one at those positions.

What changed in v2

Only 05-deck-Q1-arduino.stl has a different shape. In v1, the 4 Uno standoffs on the deck are mirrored, so a real Uno (or the custom board in pcb/) won't line up with them. v2 moves them to the right spots.

The other 25 files have the same shape in both folders. Parts already printed from v1 are fine to keep.