3D Printed Barrel Servo/Fan

Hi Tom, first of all let me thank you for providing a fantastic design for the damper. I just finished printing my RSD-BGE with Ultimaker 2, and it looks awesome.

I tried to import your .dwg file to SolidWorks, but that didn't work too well. I also tried to edit the design with Inventor, but my Autodesk skills are nonexistent, and I wasn't able to change the dimensions of existing holes. It's probably just my laking skills, but I was wondering if it would be possible for you to make an export from your CAD to a format that might be better suited for SolidWorks.

My goal is to edit the damper to be a better fit for Europeans; e.g. 1x2" opening to 25x50mm, size the RJ11 hole to fit something more easily available from EU stores than the HomeDepot jack and so on.


Thanks Antti. I'll put up solidworks compatible files in a few hours.
Thanks Tom, looking forward for the files. When I opened the RSD.dwg in Inventor, there were two designs on top of each others. One had square air outlet and the other round. Was the round a design prototype that was discarded when you published the stl files, or are/were you planning some enhancements to the current design?

Antti, sorry I haven't uploaded them yet. I'm at work and I think the IT dept has put a block on me downloading from my ftp server because my computer is popping up a message that I've never seen before about not having permission to download from this location. I'll be home tonight and will make sure to get it done.

The round outlet version was designed for someone that already had a specific diameter round pipe coming off of their smoker. The 2x1" rectangular outlet is still the preferred because it offers the least resistance to airflow.
Figured out the setting IT changed. I saved and uploaded the files as Autocad compatable .dwg. Inventor fusion doesn't have a solidworks option, but that should work.
Here is my finished servo fan. I was planning to edit Tom's files for better Euro support, but being a CAD novice had to resort to Dremel.

I used Hitec HS-65MG servo which was almost perfect fit for the servo Tom uses. I guess the BOM servo is copied from Hitec with tiny modifications to the outer dimensions. Ethernet connector needed 0.9 mm increase in the hole width, but that was also easily doable with Dremel, as I use 1.2 mm wall thickness for my functional 3D prints. After all wires were soldered and the connector in place, I secured it with hot glue so that it could be removed later on if needed.

I print with Ultimaker 2 which makes almost mirror smooth first layer, so the barrel rotates very very well against the servo case.


Tom, what are the pinouts from the RPi Ethernet jack to control the servo and fan? Whatever we want? Is there a best practice already outlined?
The colours in the cable don't really matter. What's important is that you connect the blower and fan wires to the correct pins on the cat5 jack in the damper housing.

Most jacks will have numbers along both sides, indicating what pin it connects to:


3 = Servo +5v ( Red wire from servo)
4 = Blower Ground ( Black wire from blower) and Servo Ground ( Black or Brown wire from servo)
5 = Blower +12v ( Red wire from blower )
6 = Servo Signal ( White, Yellow, or Orange wire from servo )
I drew an adapter for the barrel damper that converts its 1x2" hole to 1" BSPP thread. BSPP is British Standard Pipe with straight thread (not tapered), and is commonly used in Europe, also known as G thread or ISO 228-1.

The adapter fits snugly without screws or glue, and can be easily removed.


The STL can be downloaded here.


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Did you 3D print that adapter on your Ultimaker 2? It is beautiful! I've never been able to get threads to come out anywhere as well as that thanks to the overhang makes then sort of slop off. Any sort of tips you've got, because that adapter looks like something I'd but at the local home improvement store it looks so good.
Did you 3D print that adapter on your Ultimaker 2?

Yes, this was printed with Ultimaker 2. I've had great success with threads previously (I printed a PCB vice earlier), and pretty much default settings were used here. Layer thickness was 0.10 mm and printing speed 35 mm/s.

Ultimaker 2 makes dimensionally very accurate prints, but parts that need to fit togerther usually need a tiny bit of adjustment. For holes I often add ~1% or 0.1-0.2 mm diameter. Overhangs over 45 degrees are not picture perfect, but good enough in many cases. If you look at the thread in these pictures, I cut the thread profile straight by removing 0.50 mm from the cylinder's radius. Before that the thread was way too tight.

Tom: SW doesn't have a thread tool, at least to my knowledge. This was made with a real by-the-spec thread profile that was sweep cut along a helix path. I cheated however by downloading a 3D-model of a ready-made 1 inch pipe fitting, and reused its threaded part.
Nice job Antti. Well this work threading into a 3/4" Ball Valve? I sure do want a few of these printed up for me.

Nice job Antti. Well this work threading into a 3/4" Ball Valve? I sure do want a few of these printed up for me.


Nope, won't fit. I needed an adapter that is compatible with European pipe standards. BSP has 55 degree flanks whereas NTP is US uses 60 degrees. Depending on the diameter TPIs can also be slightly different. BSP and NTP look identical, but they have just enough differences to be incompatible :/
Guys, how is the best way to get the servo in a "home position" so that I can mount the control arm and know that it's going to be right? I'm all wired up but haven't plugged it in. I figured if I just plugged the fan/servo in with no pit probes that it would probably be closed w/ zero fan output but wasn't sure. Then I thought I should just plug it in w/ a pit probe, set the temperature high and assume that everything was wide open. I think that may be the way to go but wanted to verify.
You can set the HeaterMeter to manual mode then set it to 0% and 100% output which will give you a pretty good range. However the settings in the default config are conservative as to the endpoints so you can actually subtract some from the low or add some to the high to increase the travel range. They're intentionally not set to a point too far because some servos could be damaged if the 0% is way beyond their pulse range.