V2.4 Exhaust Housing for 120mm Fan and 4in Duct (#475)

* First commit so I can see the README

* Finished instructions and added STL files

* Update README.md

* Update README.md

* Update README.md

Images were stretch funny on mobile, remove the height=<> argument to try to fix that

* Fix overhang greater than 45 degrees

* Found a few more overhangs that needed fixing

printer_mods/README.md

@@ -132,6 +132,7 @@ like so:
 | | [Voron2.4 Y Endstop Relocation](./hartk1213/Voron2.4_Y_Endstop_Relocation) | This mod relocates the Y endstop to the top A drive piece, to work with Arkeets MGN12 mod  | :x:| :x: | :heavy_check_mark: |:x:|
 | henrikssn | [Plug Panel Mod for Generic Unfiltered Modules](./henrikssn/plug_panel_generic) | v2.4 plug panel for generic unfiltered modules with 66mm x 27mm cutout such as the Delta 06A2 and Qualtek 761-18 | :x: | :x: | :heavy_check_mark: | :x:|
 | | [Parametric Spool Holder](./henrikssn/parametric_spool_holder) | Spool holder where the length is a parameter. | :x: | :heavy_check_mark: | :heavy_check_mark: |:x:  | :heavy_check_mark:|
+| hergtoler | [Exhaust Housing for 120mm Fan and 4in Duct](./hergtoler/exhaust_120mm_duct) | v2.4 Exhaust Housing for 120mm Fan and 4in Duct | :x: | :x: | :heavy_check_mark: | :x: | :x: |
 | hernsl | [Bottom Panel Mag Clip](./hernsl/bottom_panel_mag_clip) | v2.4 magnetic clips to retain bottom panel | :x: | :x: | :heavy_check_mark: |:x:|
 |hijax_pl_ |[Corner panel clip](./hijax_pl/corner_panel_clip) |V2 panel corner frames using 3-way L brackets in the corners |:x: |:x: |:heavy_check_mark: |:x:|
 | |[Din Rail mount](./hijax_pl/din_rail_mount) |Adapter to attach DIN Rail to 2020 extrusion. |:x: |:x: |:heavy_check_mark: |:x:|

printer_mods/hergtoler/exhaust_120mm_duct/README.md

@@ -0,0 +1,59 @@
+# Voron v2.4 Exhaust 120mm with 4in Duct Adapter
+
+This mod allows use of a 120mm fan and includes an adapter to connect a 4in duct.  It does not include space for filters.  The bowden adapter has been moved to side entry.
+
+<div align="center">
+    <img src="images/exhaust_120mm_assembly.png" height=400>
+    <img src="images/exhaust_120mm_installed.jpg" height=400>
+</div>
+
+## Parts Required
+| Part | Quantity | Comment|
+|------|------|--------|
+| M3 Threaded Insert | 12 | |
+| M3x10 SHCS | 2 | |
+| M3x6 SHCS | 2 | |
+| M3x8 SHCS | 4 | |
+| M3x30 SHCS | 4 | |
+| 120mm x 120mm x 25mm fan | 1 | |
+
+## Printing
+
+- Print using standard Voron part settings and in the orientation used in the STL
+- Supports should not be needed.  There are bridging areas, but integral supports are included in the design.
+
+## Pre-Install
+
+- Install M3 threaded inserts into the printed pieces.
+<div align="center">
+    <img src="images/housing_inserts.png">
+</div>
+<div align="center">
+    <img src="images/fan_mount_inserts.png">
+</div>
+
+## Installation
+1. The standard exhaust grill and mounts will be used, and they should be installed before the new housing.
+<div align="center">
+    <img src="images/step1.png">
+</div>
+2. Remove the top middle panel clip.
+<div align="center">
+    <img src="images/step2.png">
+</div>
+3. Install the new housing using 2 M3x10 SHCS.
+<div align="center">
+    <img src="images/step3.png">
+</div>
+4. Install the bowden adapter panel mount using 2 M3x6 SHCS.
+<div align="center">
+    <img src="images/step4.png">
+</div>
+5. Install the fan mount box using 4 M3x8 SHCS.
+<div align="center">
+    <img src="images/step5.png">
+</div>
+6. Install the fan and duct adapter using 4 M3x30 SHCS.
+<div align="center">
+    <img src="images/step6.png">
+</div>