Chute — Door module

Door module

How-to guide

The per-layer door mechanism that releases parts into a bin.

Author Spencer

Contributors barthel, BrickCycleAlice and Extremetaz

Parts needed

Printed parts

Motors

Bearings

Heat inserts

16×

Screws

5× 12mm
21× 8mm

Tools needed

Hex key, 2 mm
Soldering iron or heat-set insert press

The door module is the moving half of the chute. Build it on the bench as one unit, then bolt it to the chute core. One per chute, so one per layer.

The door pivots on two bearings held in the bearing assembly. The MG995 servo, coupled through the two-piece servo adapter, swings it between its open and closed positions, and the layer's layer adapter board controls when it opens, releasing the part only once the chute stack has rotated the funnel into position over the right bin.

The fasteners and quantities are in the parts list above and are called out inline at each step.

Fastener icons match the parts list: the silhouette is the head shape, the colour is the thread size. M3 M4 M5 M6

Four things make it up:

Chute door. The flap itself, one printed part.
Bearing assembly. What the door swings on: the bearing race, a bearing holder (left) and a bearing holder (right), a bearing cover (covered side) and a bearing cover (servo side), and two 6704-2RS bearings.
Servo adapter. Two printed parts, a servo side and a flap side, that couple the servo's output to the door. The MG995 Servo Horn that comes with the servo is clasped between the two halves, then the halves are screwed together around it: 4 M3 × 8 mm countersunk screws, driven through the flap side (it's the half with the visible screw holes) into the servo side.
MG995 servo in its four-part bracket: a housing, a lower arm, a side arm and a cover. Built on the bench, in the steps below. The servo itself is not screwed to anything. It slides into the housing and the cover goes on over it, and the cover's two screws clamp the servo's mounting tabs in place.

Step 1 Preparation

Four of the module's parts take heat inserts, 16 between them. Press them all in while the parts are still bare, before anything is screwed together. See installing heat inserts for the technique.

The two bearing covers, the chute door and the two servo adapter halves take none.

Servo bracket (housing): 6 × M3, two on each of three faces. 2 take the lower arm, 2 take the side arm and 2 take the cover. The servo does not screw to the housing at all, so none of these is for it.

A printed servo bracket housing standing on end, brass heat inserts pressed into all six pockets: two on the top face, two on the front face beside the open pocket, two on the bottom edge — All six, seen from the corner. That is the only angle that catches all three faces at once. Photo: BrickCycleAlice.

Bearing race: 4 × M3, two at each end. These are the ones the holders screw down onto.

A printed bearing race lying flat, brass heat inserts in the two pockets at each end and a raised chevron in the middle of the same face — Two at each end of the race. They are on the same face as the raised chevron in the middle. Photo: BrickCycleAlice.

Bearing holder (left) and bearing holder (right): 3 × M3 each, 6 between them, on the outboard face around the bearing bore.

A printed bearing holder held at an angle, three brass heat inserts spaced around its empty bearing bore, one on the small ear and two on the body — Three around the bore on the outboard face. One holder is shown; the other takes the same three. Photo: BrickCycleAlice.

The photos are of printed parts with the inserts already pressed in, one part at a time, so the brass is what you count.

No bench vice? Stand a bearing holder in the servo bracket housing while you press its inserts. The housing's pocket holds the holder upright and square, and leaves both your hands for the iron. Tip: BrickCycleAlice.

A bearing holder with its three brass inserts standing against the open servo bracket housing, which props it upright on the bench — A holder propped in the housing, which is steady enough to press against. Photo: BrickCycleAlice.

One more sub-assembly goes together here, before the step that uses it, and it takes no inserts.

The two 6704-2RS bearings: one into the bearing holder (left), one into the bearing holder (right). There is no wrong way round. Push each one square into the bore until it stops. Home is not the bottom of the pocket: the bearing comes up against a small lip inside the bore and sits proud of the floor, so stop when it stops rather than pushing for flush.

Both printed bearing holders with a 6704-2RS bearing pushed into each bore, a ring of printed plastic still visible around the bearing's outer race, and three brass heat inserts around each face — Both holders with their bearings pushed home. The ring of plastic still showing around each bearing is the lip it has stopped against. Photo: BrickCycleAlice.

Step 2 Slide the servo into the housing and close it with the cover

The servo is not screwed down. Slide the MG995 into the housing's pocket, then lay the cover over the open face and drive its 2 M3 × 12 mm countersunk screws into the housing's inserts. Tightening those two is what holds the servo: the cover traps the servo's mounting tabs between itself and the housing.

Use the 12 mm here, not the 8 mm. Snug both down evenly rather than pulling one home first, so the cover seats flat on the tabs.

Render of the servo bracket housing with the cover pulled off it, showing the open pocket the servo slides into and the two screw lugs that line up between the cover and the housing — The cover pulled off the housing. The servo goes into the open pocket, and the two lugs the cover screws through are the only fasteners holding it. Rendered from the part geometry, not from a build. Render: Balloon.

An MG995 servo lying in the open pocket of the printed housing with the cover off, its mounting tabs resting across the two brass-lined lugs and its lead running out of the bottom of the pocket — Servo in, cover still off. Its tabs lie across the two lugs and nothing screws into the servo itself. Photo: BrickCycleAlice.

The same housing from the corner with the cover screwed down over the servo, two countersunk screw heads in the cover and the servo's splined output standing through the window in it — Cover on, both screws snugged down evenly. That pair is what holds the servo in. Photo: BrickCycleAlice.

Step 3 Add the bracket arms

The two arms land on two other faces of the housing. They do not take the same screw, so tell them apart before you pick one up.

The side arm is the flat slab that covers the whole side of the housing. Its screws finish flush with the face.
The lower arm is the narrower one that goes under the housing and tapers into a raised end. Its screws finish at the bottom of a deep round well.

Side arm: 2 M3 × 12 mm countersunk into the housing's inserts. Use the 12 mm on this arm.

The servo bracket housing with the side arm bolted to it, seen from the cover side, the slab standing proud of the housing with a single empty hole in its foot — The side arm on. The empty hole in its foot is the one that bolts to the chute core later, not now. Photo: BrickCycleAlice.

The same assembly from the servo output end, with the side arm's two screw heads sitting flush in their countersinks and the servo's splined output above them — From the output end, with the side arm's two screws driven home. They finish flush with the face. Photo: BrickCycleAlice.

Lower arm: 2 M3 × 8 mm countersunk into the housing's inserts. Use the 8 mm on this arm.

Both arms now on the housing: the side arm slab across the top and the lower arm projecting from the right-hand face with an empty hole in its raised end — Lower arm added, so both arms are now on. Its raised end carries the second empty hole. Photo: BrickCycleAlice.

The finished bracket from below with both arms fitted, the lower arm's two screw heads sunk at the bottom of their round counterbores and the servo's output shaft visible between the arms — The finished bracket from below, both arms fitted. The lower arm's two screws sit down in their wells, not flush. Photo: BrickCycleAlice.

Each arm has one further hole, in the ear at its far end. Those two are not driven here; they are what bolts the finished bracket to the chute core in step 8, so leave them empty.

Step 4 Hang the door on its bearings and the race

The shaft is captured at both ends once this is together, so there is only one order it goes in: the holders have to go onto the shaft before anything is bolted down.

Check which way round the door goes first. The shaft runs the length of the door's top edge, and one end finishes in a hexagonal spigot. That hex end is the servo side: it is what the servo adapter's flap-side half slides onto in step 8. The other end is plain round.

Check the race is the right way round before any of this is bolted up. The shaft sits high on the door's axis and the race's step tucks down and under it, so laid together correctly the race and the door read as one flat plane. If they look like a flight of stairs, the race is round the wrong way. Getting it wrong is a lot of screws to undo. Tip: BrickCycleAlice.

The two parts before they go together, and the orientation to get right: the race's step goes down and under the shaft. Photo: BrickCycleAlice.

The door and race sighted along their length from the hexagonal end of the shaft, the top of the race and the top of the door lying in one continuous flat plane — Right way round, sighted along the joint: one flat plane across both, no step to walk up. Photo: BrickCycleAlice.

Slide a holder onto each end of the shaft, bearings already seated. Neither should need forcing.
Lay the race along the back of the shaft, on the opposite side from the flap, and bolt each holder down onto its end of it: 2 M3 × 8 mm countersunk per holder, 4 in total, into the race's four inserts. The holder seats flat against the race's end. The race arches over the shaft and never touches it; if it does touch, something is not seated.

Close view of one end of the assembled flap: the bearing holder bolted to the end of the bearing race with two countersunk screws in its face, the bearing seated in its bore with the door's shaft through it, and the door plate above — One end, done. The holder is bolted to the end of the race and the shaft runs through its bearing. Photo: BrickCycleAlice.

Two renders, one above the other: on top the chute door with its shaft, the bearing race over the shaft, and the two bearing holders drawn out along the shaft with a blue bearing in each; below, the same parts pushed together so the holders sit on the ends of the race — The holders, with their bearings in blue, going onto the ends of the shaft and down onto the race. The covers are not shown. Rendered from the parts' own geometry in assembly position, not from a build. Render: Balloon.

Hung this way the door swings between the two positions below, and it stops against the race at both ends.

Render of the assembled door module seen from the servo end at an angle, with the chute door drawn twice: once in grey lying almost flat, and once in orange hanging almost vertically, both pivoting on the same shaft below the bearing race — The two ends of the door's swing. Grey is the flattest it goes, orange the steepest. The covers are not shown. Rendered from the parts' own geometry, not from a build. Render: Balloon.

Step 5 Fit the bearing covers

The two covers are not the same part. The Bearing cover (servo) has an open centre and goes on the hex end of the shaft. The Bearing cover (covered) is closed and goes on the plain end.

Put one on each holder with 3 M3 × 8 mm countersunk each, 6 in total, into the three inserts pressed in step 1. The cover's raised rim drops into the pocket on top of the bearing and clamps it against the step: if a bearing has not gone fully home against its lip, its cover will not pull flat. The covers are thin at the rim, so snug the three screws down evenly rather than tightening one fully first.

Each cover has two further holes that stay empty here — they take the screws that hold the flap assembly to the chute core in step 6.

The flap assembly with a round bearing cover fitted on the near end, its screws driven around the rim, the door plate running away to the right — One end covered. The two holes left empty in the rim are for step 6. Photo: BrickCycleAlice.

The whole flap assembly with both covers on, the near cover showing the open centre the shaft comes through and the far cover closed — Both on, and the difference visible: the near one is open for the shaft, the far one is closed. Photo: BrickCycleAlice.

Step 6 Bolt the flap assembly to the chute core

Six of the core's 18 inserts belong to this module. Four are used here, two in step 8:

2 bearing covers, 4 M3 × 8 mm countersunk in total, 2 per cover. These are the two holes left empty in each cover in step 5.
Servo bracket lower arm, 1 M3 × 12 mm countersunk , and side arm, 1 M3 × 8 mm countersunk — step 8.

Render of the servo side of the chute core with four heat inserts circled in red — The long side the servo sits on: two inserts for that side's bearing cover, two for the servo bracket arms. Render: Balloon.

Render of the other long side of the chute core with two heat inserts circled in red — The other long side: two inserts, both for the second bearing cover. Render: Balloon.

The covers are what hold the flap on. Nothing else in the bearing assembly touches the core: the race and the holders are carried by the two covers, which are already screwed to the holders from step 5. Offer the whole assembly up so a cover lands on each long side of the core, and drive 2 screws per cover into the inserts above.

Snug all four down before tightening any of them, then cycle the door by hand through its full swing. It should turn freely on the bearings and not touch the core anywhere; if it binds, slacken off and let the assembly settle square before tightening again.

The flap assembly being offered up to the chute core, one bearing cover standing proud of the core's long side before its screws go in — How it goes in: a cover lands on each long side of the core, and the two screws per cover go in from there. Photo: BrickCycleAlice.

The flap bolted to the core, seen down onto the top face, with the door closed so no blade shows below the core — Bolted down, door fully closed: nothing showing below the core. Photo: BrickCycleAlice.

The same assembly with the door fully open, the thin door plate hanging down clear of the core — Door fully open, the plate hanging clear. Photo: BrickCycleAlice.

The other side of the same assembly, the bearing cover with the hexagonal socket in the middle, door closed — The other side, door closed. This is the cover with the hex socket, so this end faces the servo. Photo: BrickCycleAlice.

The same side with the door fully open, the door plate hanging below the core — The other side, door open. Photo: BrickCycleAlice.

The assembly end on from the back with the door closed, four brass inserts in the flat top plate and the bearing race with its chevron sitting between the two holders — From the back with the door closed: the race and its chevron sit between the two holders. Photo: BrickCycleAlice.

Step 7 Build the servo adapter

The servo-side and flap-side plates clamp the MG995 Servo Horn between them. The horn ships with the servo, it isn't printed. Drop the horn into the servo-side half splined sleeve first: the sleeve sits in the hole in the middle of that half and the two arms lie in the slot around it. It does not fit any other way. Bring the flap-side half down over it and drive 4 M3 × 8 mm countersunk screws through the flap side (it's the half with the visible screw holes) into the servo side. The screws cut their own thread in the printed plastic.

The four screw holes are not spaced evenly around the centre, so the flap side only drops on in two of the four quarter turns. Line all four holes up by eye before you press the halves together, rather than finding out on the third screw. Tip: BrickCycleAlice.

The MG995 Servo Horn, a two-arm splined servo arm that ships with the servo, with its splined sleeve facing to the right — The MG995 Servo Horn. The splined sleeve, facing right here, is what goes into the servo-side (tan) half in the next picture; on the machine it is also what slides onto the servo's output shaft. Reference photo of the stock part, not from a build. Photographer not recorded.

Exploded render of the two servo adapter halves facing each other: the flap-side half in blue on the left showing its hexagonal socket and four countersunk holes, the servo-side half in tan on the right showing the long slot the two-arm horn seats in and its four pilot holes — Exploded, in build order. The horn goes into the servo-side half (tan), sleeve into the middle hole and arms in the slot, then the flap-side half (blue) goes over it and takes the 4 screws. The hex socket in the flap side is what the door's shaft ends up in. Rendered from the part geometry in assembly position, not from a build. Render: Balloon.

The finished servo adapter seen from the servo side: the black two-arm horn lying flush in its slot in the grey printed disc, the splined sleeve's opening in the middle of it and four empty countersunk holes around the face — Finished, servo side. The horn sits flush in its slot with the splined sleeve in the middle, and that opening is what goes onto the servo's output shaft. Photo: BrickCycleAlice.

The same adapter from the flap side: a raised hub with a hexagonal socket in the middle and the four countersunk screws driven from this face around it — The other side, and the one to check: four screws home, and the hexagonal socket in the raised hub that takes the hex end of the door's shaft. Photo: BrickCycleAlice.

Step 8 Bolt the servo bracket on and couple it to the door

Watch the video below before you finish this step. It is possible to break a door here. See how the coupling is set in the video before you commit to a position. Tip: BrickCycleAlice.

The bracket goes on the same long side as the servo-side bearing cover, into the other two inserts in the first render above. The two arms do not take the same screw here either:

Lower arm, 1 M3 × 12 mm countersunk .
Side arm, 1 M3 × 8 mm countersunk .

Then couple the servo to the door through the two-piece adapter you built in the step above. Its servo side goes onto the servo's splined output, through the horn clasped inside it, and its flap side has a hexagonal socket that takes the hex end of the door's shaft, the end step 4 told you to point at the servo. It is a slip fit, so it pushes on without force.

Clock it before you commit: centre the servo (or let it settle at its power-on default), fit the adapter at roughly the middle of the door's swing, then fine-tune once you can check both open and closed by eye. The video below shows how it is set.

Photograph of a real door module part-way through assembly: a hand holds the assembled servo adapter, a white disc with a hexagonal boss in the middle and four countersunk screws around it, in front of the MG995 in its printed bracket — The same job on a real machine. The disc in frame is the servo adapter from step 7, screwed together with its four countersunk screws, with the hexagonal socket that takes the door's shaft facing the camera; the MG995 sits in its bracket behind it. Frame from the video below. Video: Spencer.

The servo bracket bolted to the chute core with the servo adapter fitted on the servo's output, seen face on, the adapter's four screws and hex socket visible — Bracket bolted on and the adapter fitted to the servo, seen face on. Photo: BrickCycleAlice.

The same assembly from above, the servo in its bracket standing off the chute core with the door hanging below — From above, with the servo standing off the core and the door below. Photo: BrickCycleAlice.

The MG995 only rotates 180°. Install the servo so the door can reach both its fully open and fully closed positions inside that range: clock the horn and set the mounting angle so neither extreme falls outside the servo's travel. Before you tighten anything down, cycle the door by hand through both positions to confirm it swings freely and doesn't bind on the bearings or the core.

Video: Spencer.

The finished result

The module is finished when the bracket is on the core and the adapter couples the servo to the door, and the door swings freely through its whole travel. One of these per layer.

A finished door module bolted to a chute core: the MG995 in its printed bracket with its lead looped out to a bare connector, the bracket's arms screwed to the core's side, and the light grey door plate hanging below the core — A finished module on its core: the servo in its bracket, the adapter coupled to the door's shaft, and the door hanging below. Photo: BrickCycleAlice.

The Chute core page carries the other three sub-assemblies that go on the same core, and is where you should return once you're done here.