Universal Single 120 mm Fan to 6″ Duct Shroud

Description

120 mm fan to 6-inch duct adapter, drawn as one piece

This 120 mm fan to 6-inch duct adapter takes one standard 120 mm exhaust fan and hands everything it moves to a 6-inch duct. D-Central drew it in-house around the fan flange and the collar, then built it as a single continuous body — no seams to leak air, no glued joints, no fasteners to work loose across a few thousand heat-and-cool cycles.

A bare fan blowing into open air throws heat in every direction at once, and radiates its noise the same way. Capture that column and hand it to a duct, and an uncontrolled heat source becomes a single steerable exhaust path — the difference between a machine you tolerate in the basement and one you place on purpose.

It is the workhorse of the line: single-fan hashboard benches, Antminer S9-class hardware, PSU exhaust fans, older machines, home-built enclosures.

What it fits: any standard 120 mm fan, out to 6-inch duct

The intake face is drawn to the standard 120 × 120 mm fan flange on its 105 mm screw square — the pitch shared by essentially every conventional 120 mm fan, from Antminer S9-family exhaust fans to PSU, enclosure and case fans. The stock fan stays fitted and nothing electrical is touched.

The outlet is a 6-inch collar for ordinary flexible or rigid duct, the same diameter AC Infinity Cloudline S6 and T6 class inline fans use.

Two 120 mm fans on one exhaust face, as on an S19 or S21? Use the Antminer S19 / S21 Dual 120 mm to 6″ Duct Shroud, which merges both fan columns before the transition. Running 140 mm fans, as the Whatsminer M-series does? Take the Whatsminer 140 mm Fan to 6″ Duct Shroud. Already on 8-inch duct downstream? The Universal Single 120 mm Fan to 8″ Duct Shroud saves you a reduction at the worst place in a run: the first fitting.

How it installs

1. Seat the shroud over the exhaust side of the fan, square to the flange.
2. Slide 6-inch flexible or rigid duct over the collar.
3. Band-clamp the duct down and snug it.
4. Route the run where the heat belongs: a window port, a wall penetration, a shop or garage, or an inline fan feeding a longer trunk.

One screwdriver for the band clamp is the whole tool list: no fan swap, no wiring.

Why a shaped body beats a plate with a hole in it

The cheap way to make this part is a flat plate with a round cut-out. Air leaving the blades then turns a hard corner immediately, where it is fastest and least organised, and the corners of the square fan face become dead pockets that spill pressure instead of passing it along. This body makes the change gradually, across its full 95 mm depth, into a 6-inch round slightly larger in area than the square face feeding it: a gentle expansion rather than a squeeze.

PETG keeps its shape under sustained exhaust-side warmth, where cheaper printing plastics soften and sag away from the collar.

• Captures the whole 120 mm fan face rather than a circle cut out of the middle of it
• Turns square into round across the depth of the body, not at one hard step
• Seats on the standard 105 mm screw square, so it goes onto the fan you already own
• Holds its geometry in sustained exhaust heat — PETG, not a low-temperature plastic
• Arrives finished in one piece: nothing to assemble, nothing to glue, nothing to lose

Specifications

Open source — print it yourself, or buy it finished

D-Central designs these parts and gives the designs away. This one is released under CC BY-SA 4.0 through our 3D models download center: free to download, modify, remix, print and sell, with no licence to buy and nothing held back behind a purchase.

D-Central Technologies drew this geometry and open-sourced it. It is ours — not a remix, not a re-hosted file. The model has its own card at the 120 mm to 6-inch shroud entry, and the file is one click away: single_120_to_6in.zip holds the STL, the CC BY-SA 4.0 licence and the installation and safety guide.

What this listing buys is the finished part: made to order in PETG, in black or orange, and shipped from Montreal, Quebec, ready to clamp a duct onto. The files stay free either way — buying the printed part, or backing D-Central’s fund page directly, is what pays for the next design in the line.

Works with

• Universal Single 120 mm Fan to 8″ Duct Shroud — longer runs
• Antminer S9 Single 120 mm to 6″ Duct Shroud — S9-specific body
• Single 120 mm to 6″ Expansion-Chamber Shroud Silencer — same fit, chamber in the path
• 120 mm Intake Filter Ring — dust control, cold end
• 6″ 45° Duct Elbow — turn without kinking flex

See the full D-Central shroud and ducting system for the compatibility matrix and sizing guide.

Frequently asked questions