🗜️ Bracket

📌 What

A clamp that wraps a device from above or below and hangs it in a HomeRacker frame. A shell grips the device, mount wings on both flanks cap the vertical supports and take a lock pin each.

🤔 Why

Devices come in arbitrary sizes, HomeRacker supports sit on a 15mm grid. The wings absorb the difference: each one widens by half of what the device width misses on the grid, so the lock pin holes land on a support whatever the device measures. Nothing below/above the device, so airflow and cabling stay clear.

🔧 How

Open parts/bracket.scad in OpenSCAD and use the Customizer panel.

Measure the device itself, not a gap. The standard 0.2mm TOLERANCE is added internally.

The 50mm ceiling on both strengths is a Customizer slider bound, not a limit of the model. Through the library or a -D override they take any value from 2mm up and clamp as described under ⚠️ Limits, which is what the strength_sides=200 render command below does.

Library usage, include in your own model:

include <../bracket/lib/bracket.scad>

bracket(device_width=100, device_depth=99, device_height=25.5);

Implemented as a BOSL2 attachable. bracket_shell(), bracket_mount() and bracket_mount_pair() are exposed for composing the halves separately. An optional color parameter overrides the default yellow.

🧭 Mount axis and gap units

A HomeRacker frame has supports running both ways. By default the wings hook the ones running along the device face (mount_axis="x"), which is what most devices want. Set mount_axis="y" and the caps turn a quarter turn to hook the supports running front to back along the sides of the frame instead.

That matters when a device is wide enough that the wings plus the connector arms eat the rack’s usable width. A device wider than 164,8mm in a 10” rack is the usual case: on the X axis it does not fit, which forces a 19” rack, a tray or going off-standard (full HomeRacker). Hooking the frame sides instead moves the pins out of the contested span.

mount_gap_units widens the span between the wings by whole units, and it does two jobs:

• Reach. Extra units push the wings out to supports further away, which is how a mount_axis="y" bracket reaches the sides of the frame.
• Centring. An odd count lands on the left first (1 goes left, 2 one per side, 3 puts two left and one right), so the device sits off-centre between the supports. That is how you centre a device in a frame whose unit count does not divide evenly.

Both work on either axis.

Two things behave differently on the Y axis:

• Column spacing steps two units at a time and mount_offset_y rounds to a whole unit, because the pins go through the frame’s own hole grid. Where rounding up would push the outer cap past the back of the shell, the offset steps down to the last unit that fits. Spacing comes out slightly narrower than the same device gets on X.
• The span clears the device edge by 2.1mm, the amount a sideways cap reaches back. A width in the last 2.1mm before a grid line costs a whole unit: 100.6mm still fits a 105mm span, 100.7mm steps out to 120mm.

⚠️ Limits

Seven inputs are refused outright, with an assertion naming the value that would work.

Three inputs are silently clamped at the top end rather than refused, because the clamped result is still the part you asked for:

• strength_top caps at half the smaller device dimension, where the top plate closes over entirely.
• strength_sides caps at device_height - 2mm.
• mount_columns = 0 picks two columns from a device depth of 45 + mount_offset_y, one below that.

One thing to know before composing with the module: the attachable bounding box covers the shell only. The wings reach past it on all three axes, outward in X by a wing width each side, down in Z by roughly the device height plus a support unit, and in Y wherever mount_offset_y puts them. Anchor against the shell, then place anything near the wings by hand.

📸 Catalog

Part	Preview
Bracket

Variants

Each of these shows one behavior the module applies on its own.

Single column (shallow device)	Forced single column	Wide wings (width near a grid line)
device_depth of 30 is under the two-column threshold, so one column per side	200mm deep but pinned to one column, which saves material on a light device	A 90mm device sits just past a grid line, so each wing grows to 22.4mm to reach the support. The lock pin hole stays on the grid

Mount offset	Closed top plate	Deep side walls
mount_offset_y of 34 pushes both columns back, which is how a bracket clears a front panel	strength_top of 50 hits the cap on a 99mm device, closing the window and dropping its chamfer	strength_sides of 200 clamps to device_height - 2, wrapping a 120mm device almost to the bottom

Minimum strengths	Y axis	Odd gap units
Both strengths at their 2mm floor, the thinnest shell the module will build	mount_axis="y", caps turned a quarter turn to hook the frame sides	mount_gap_units=1 lands on the left, shifting the device within the frame

Y axis reaching out
mount_axis="y" with mount_gap_units=3, reaching past the near supports to the frame sides

To generate or refresh the renders (full F6 renders via scadm export-png):

scadm export-png models/bracket/parts/bracket.scad
scadm export-png models/bracket/parts/bracket.scad -D device_depth=30 --output models/bracket/parts/renders/bracket_single_column.png
scadm export-png models/bracket/parts/bracket.scad -D device_depth=200 -D mount_columns=1 --output models/bracket/parts/renders/bracket_forced_single.png
scadm export-png models/bracket/parts/bracket.scad -D device_width=90 --output models/bracket/parts/renders/bracket_wide_wings.png
scadm export-png models/bracket/parts/bracket.scad -D device_depth=200 -D mount_offset_y=34 --output models/bracket/parts/renders/bracket_mount_offset.png
scadm export-png models/bracket/parts/bracket.scad -D strength_top=50 --output models/bracket/parts/renders/bracket_closed_top.png
scadm export-png models/bracket/parts/bracket.scad -D strength_top=2 -D strength_sides=2 --output models/bracket/parts/renders/bracket_min_strength.png
scadm export-png models/bracket/parts/bracket.scad -D device_height=120 -D strength_sides=200 --output models/bracket/parts/renders/bracket_deep_sides.png
scadm export-png models/bracket/parts/bracket.scad -D 'mount_axis="y"' --output models/bracket/parts/renders/bracket_axis_y.png
scadm export-png models/bracket/parts/bracket.scad -D mount_gap_units=1 --output models/bracket/parts/renders/bracket_gap_odd.png
scadm export-png models/bracket/parts/bracket.scad -D 'mount_axis="y"' -D mount_gap_units=3 --output models/bracket/parts/renders/bracket_axis_y_gap.png

📚 References

• HomeRacker core: base constants, lock pins and supports
• Sleeve: the other reusable way to attach to a support
• Return the bracket to the open-source catalog: why the module lives here