8″ 45° Duct Elbow

Description

8 inch 45 degree duct elbow for trunk lines

An 8 inch 45 degree duct elbow protects the decision you already made. Nobody runs 8-inch duct by accident: you sized up because you wanted the machine to breathe with as little restriction as the building allows. Dropping a sharp corner into that trunk quietly undoes a good part of it. A gentle 45 changes the run’s direction without asking the air to do anything violent about it.

Full 8-inch bore is carried through the turn, so the cross-section never pinches mid-bend. Standard 8-inch collars on both ends, matching every 8-inch shroud, silencer, coupler, wye and port in the D-Central line.

Drawn in-house and printed as one continuous body. On a fitting this size that also means there is no glued seam sitting in the highest-velocity part of the run.

What it fits

Standard 8-inch duct on both ends, rigid or flexible. It mates directly to the trunk collar of the 8″ to Dual 6″ Y-Splitter, the inside collar of the 8″ Window Exhaust Port, and the outlet of any 8-inch shroud such as the Antminer S19 / S21 Dual 120 mm to 8″ Duct Shroud. For 6-inch runs the same fitting is the 6″ 45° Duct Elbow. Where a full right angle has to happen inside a tight envelope, use the 8″ 90° Duct Elbow (Compact); where you have room for a sweep in a single fitting, the 8-Inch Long-Radius 90° Airflow Duct Elbow.

How it is used

Change direction with one. Make a right angle with two and a short straight between them. Chain three or four to walk the trunk around a beam, along a rafter line, or up a wall in shallow steps rather than square corners. Because a 45 can be clocked to any orientation around the duct axis before you tighten the clamps, the same fitting handles a turn sideways, a rise, or any combination of the two — which is what real routing usually needs.

Why gentle turns matter more on a big trunk

Bend loss scales with how tightly the flow is asked to turn. On a trunk carrying the full output of a hard-working machine, the same fitting geometry acts on more air, so the same mistake costs more. There is also a noise argument: a sharp corner sheds turbulence that the rest of the duct then broadcasts as low-frequency rumble. A gentle turn is quieter for the same reason it is cheaper in pressure, and neither effect requires anything exotic to explain.

• Holds full 8-inch bore through the bend so the trunk never pinches
• Substitutes for a sharp corner wherever the layout gives you the length
• Chains into shallow doglegs that clear beams and rafters without square corners
• Clocks freely around the duct axis before the clamps go on
• Sheds less turbulence into the run, which is where duct rumble comes from

Specifications

Open source — drawn here, published free

Every fitting in this line is D-Central Technologies’ own drawing — designed here, measured here, open-sourced here — and each one is released under CC BY-SA 4.0 at the 3D models download center. Free to download, modify, remix, print and sell. This one lives at the 8″ 45° elbow model card. It is a big part and a long build, so plenty of people would rather buy it than tie up a machine for it — both routes are legitimate and both stay open.

Direct file: elbow_45_8.zip, containing the STL, the CC BY-SA 4.0 licence, and the installation and safety guide. This page sells the finished elbow instead: made to order in PETG, in black or in orange, shipped from Montreal, Quebec, collars cut to the same standard as the rest of the run. The download costs nothing and always will; the part and D-Central’s fund page are what fund the next drawing.

Works with

• 6″ 45° Duct Elbow
• 8-Inch Long-Radius 90° Airflow Duct Elbow
• 8″ Duct Coupler
• 8″ to 6″ Duct Reducer
• Antminer S19 / S21 Dual 120 mm to 8″ Expansion-Chamber Shroud Silencer

Every fitting in the chain from one shop, cut to one standard: see the D-Central shroud and ducting system.

Frequently asked questions