Bin frame — Bottom layer

Bottom layer

How-to guide

The layer the machine stands on. A regular layer with foot extensions in place of piece C, and the casters under them.

Author Spencer

Contributors BrickCycleAlice, Christoph, Daddy-O's Bricks - Bill and Dov2000

Parts needed

Printed parts

Aluminum extrusion (2020)

6× 231mm
2020 aluminum extrusion, cut to 231 mm (piece D).

Wheels

Screws

36× 16mm

A an interchangeable alternative works (hover for what).

Tools needed

Hex key, 3 mm for a button head or 4 mm for a socket head
Tape measure

The bottom layer is an ordinary bin layer that also carries the machine. Its vertical extrusion is one long piece per corner instead of a layer's worth: the caster screws into the bottom of it and the layer above lands on the top of it.

Build it after a regular layer, not before. Everything here is a regular layer with three differences at floor level, so that page is the one that describes the layer and this one only covers what changes: piece D in place of piece C, an External bracket — foot cover in place of the cover and the External bracket — bottom vertical at the bottom of the corner, and the feet.

Build a hex frame before you start, and leave the six External bracket — covers off this one. It is a required component of this page, not covered here.

A finished hex frame from above: six B spokes and their printed crossbeams forming the inner ring inside the aluminum outer hexagon, with a printed corner bracket at each of the six vertices — A finished hex frame. Photo: BrickCycleAlice.

Piece D is 2020 aluminum extrusion, cut to length. The framing cut list has the exact dimensions.

This layer uses 6 × piece D (Foot extension), 231 mm, and no piece C. Every layer above it takes its own piece C, so an N-layer machine needs 6 × D and 6 × (N−1) × C.

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

Step 1 Close off the corners at floor level

The bottom layer does not get an External bracket — cover, and it does not get an External bracket — bottom vertical below its frame the way every other layer does. It gets an External bracket — foot cover instead, one per corner, which is the single printed part that replaces both of them.

Fit it now, before any extrusion goes in. It takes 2 M5 × 16 mm socket / button head screws through its outer holes into the External bracket — side, and it is awkward to fit once piece D is through the corner.

Close-up of the foot cover bolted to the External bracket — side, with the two foot-cover screws and the extrusion mounting screws visible — The foot cover to External bracket connection, with the extrusion socket open at the top. Photo courtesy of BrickCycleAlice.

Step 2 Run the foot extensions through the corners

One corner of a built machine close up, with the C layer vertical support marked by an arrow between the two frames above and the longer D foot extension marked by an arrow running from the caster up past the bottom frame to the second — One corner of a standing machine, close up. D runs from the caster, past this layer's corner, up to the layer above; C is the ordinary vertical between the layers further up. Photo courtesy of Christoph in the basically Discord.

The corner itself is the same as on any layer. Only the vertical changes: piece D takes the place of piece C, and it stands proud at the bottom instead of being capped.

On each of the six corners:

Partially thread the 2 M5 × 16 mm socket / button head screws that clamp the collar onto the extrusion, at the holes near the bottom of the External bracket — side, so they are started but not yet tight.
Slide a piece D down through the corner, from above, until it stands out below the foot cover.
Before tightening anything, measure from the bottom of the External bracket — foot cover to the end of piece D. It should stand out about 54 mm.
Tighten the 2 collar screws, bracing against the extrusion.

Piece D held against the bracket with a tape measure alongside, measuring from the bottom before the collar screws are tightened — Measuring piece D from the bottom before the collar screws are tightened down. Photo courtesy of BrickCycleAlice.

Driving one of the collar screws home with a hex key once piece D is positioned — Tightening the collar screw once piece D is positioned. Photo courtesy of BrickCycleAlice.

Piece D stands about 54 mm clear of the bottom of the foot cover. The 2020 M6 foot connector bolts into that exposed end.

Vertical cross-section through one corner at the bottom of the machine, showing piece D running through the bottom layer's bracket and up into the layer above, the foot cover around it, and the exposed end below — One corner at floor level, cut through the centre of the profile. The bottom layer is blue, the collar of the layer above purple. The numbers match the list below. Click to enlarge. Drawn from the part geometry rather than from a build, by Balloon.

The numbers on the drawing:

External bracket — side, the same collar as on any layer, at this layer's frame.
External bracket — foot cover in place of the bottom vertical and cover.
Piece D, 231 mm cut. It runs from below this layer, through its collar, and up to 3 mm below the flange face of the collar above, so it spans the whole gap to the next layer as well as reaching the floor.
Two M5 × 16 mm socket / button head screws clamp this layer's collar onto piece D, and two more clamp the External bracket — bottom vertical onto it in step 4. Same screws, same holes as on a regular layer.
The exposed end of piece D, which takes the 2020 M6 foot connector and the caster. It stands about 54 mm below the foot cover.
The collar of the layer above, sitting on the External bracket — bottom vertical fitted in step 4. From here up, every joint is the ordinary layer joint described on Stacking the layers.

Step 3 Fit the feet

Fit all six casters before the machine gets any taller. A bin tower on five feet is not something you want to discover at four layers.

Bolt a 2020 M6 foot connector into the open bottom end of each piece D. The connector is an aluminum bracket made for the end of 2020 extrusion and comes with its own bolts and nuts.

Screw a swivel stem caster (M6 × 15 mm) into the connector's M6 thread. The casters have brakes; leave them on while you build.

Step 4 Cap each extrusion with the bottom vertical bracket

This is the step that turns the bottom layer into an ordinary layer as far as everything above it is concerned. Slide an External bracket — bottom vertical onto the length of piece D standing above the frame, ensuring its angles align at the bottom, and secure it with 2 M5 × 16 mm socket / button head screws through its outer holes. It is the same part, fitted the same way, as on a regular layer.

One corner of the bottom layer seen close up from above: the External bracket — bottom vertical standing on the collar with the end of piece D recessed in its square socket, the foot cover below the frame, and the caster under that — One finished corner, from the collar up to the socket the next layer lands on and down to the caster. The end of piece D sits a few millimetres below the top face of the bracket, which is what it should look like. Photo: BrickCycleAlice.

Matching parts from the same print run are embossed with a shared set code (e.g. "b2") on both the External bracket — side and the External bracket — bottom vertical. Keep marked pairs together so brackets don't get mixed across corners.

The finished result

One hexagon closed, six casters on, and every corner ending in a bottom vertical bracket ready for the next layer.

Image coming: the whole layer on its casters, with nothing yet fitted under the spokes

The Bin frame page contains the instructions for the entire stack, and is where you should return once you're done here.