1/4 Scale ACA Screamer 105 Siren

Here it is!! The new member to the 1/4 scale ACA lineup is the Screamer 105!!

This project is very special to me since I got the privilege to actually see one in person be the first to take measurements and inside photos of it along with my friend Miles (milk_models)! I'd also like to thank him and his dad for driving me on a 10 hour round trip to see the siren all the way in North Washington.  

In case you're curious and want to see some of those photos/videos, check out this video from my second channel which shows some pretty neat close-ups and images:

With all of that aside, the rest of this description will be the parts list and all the instructions to build/assemble the siren with photos to hopefully aid you along the way!

PARTS LIST:

Motor: https://www.amazon.com/uxcell-Micro-11600-12000RPM-Remote-Control/dp/B07M8FJBQZ/ref

Bearings: https://a.co/d/45fWKgO

M3 Hardware Kit: https://www.amazon.com/Machine-Assorted-Assortment-Stainless-Threaded/dp/B0DFWYBJJJ/

M2 Hardware Kit: https://www.amazon.com/Machine-Assorted-Stainless-Assortment-Threaded/dp/B0DFWXRM21/ref

M2 Threaded Inserts: https://www.amazon.com/ruthex-Threaded-Insert-pieces-ultrasound/dp/B088QJG676/ref

Random Hardware Kit (M2.5): https://www.amazon.com/AvrestYPT-Stainless-Assortment-Phillips-Electronics/dp/B0F8V7G8T8/ref

POWER SUPPLY (OPTIONAL):

Power Supply https://www.amazon.com/Adapter-100-240V-50-60Hz-Converter-Transformer/dp/B0D7GGGM6Q/ref

Speed Controller: https://www.amazon.com/RioRandTM-Upgraded-6V-90V-Motor-Controller/dp/B00F839VNQ/ref

ASSEMBLY INSTRUCTIONS

The assembly for the 105 is quite simple but it can be a bit hard to understand how it's put together. In terms of difficulty, I'd say it's harder than the 1/4 scale model 2 but still not terribly hard to build.

To start, you'll want to print the tolerance tool to test what the best press fit on your motor shaft is. You don't want it to be very loose but also not super tight. Which ever hole fits your motor the best, print the rotor that corresponds to the little number marked underneath the hole size on the tolerance tool.

Next, you'll want to print your main motor body. Make SURE that all the little support lines (even tiny ones) from the underside of where the motor fits inside are removed (I usually use a tiny flathead screwdriver to pry them out)

From here, insert the motor up through the bottom of the motor cover and push it through the little hole at the top. You may need to take an x-acto knife and scrape out the inside of the little hole in order for the motor to fit through nicely (just keep in mind the brim of the motor won't poke all the way through the top). Once you have it in place with both of the inside motor threads lined up with the two little outer holes, take you're M2.5 bolts from the random hardware kit and bolt two of them into each motor thread to lock the motor into place.

Before you attempt to press the rotor onto the motor shaft, you'll probably want to sand the shaft down a bit to make sure your fan can fit on nicely. Trust me, it's a lot easier and safer to do this step now than with the rotor inside the assembly. To do this, print your fan and start slowly sanding the top of the rotor's 3D printed shaft repeatedly until you can (with a decent bit of force) press the fan onto the shaft. It doesn't need to be super tight nor super loose. If it's too loose, you can always super glue or weld it to the shaft later!

Now you can press your rotor into place on the shaft! If it's scraping heavily, consider sanding either the sides of the rotor itself OR the inside of the stator. However if it's just scraping/tapping a tiny bit, there's a chance the bearing will fix it so don't get too worried!

As for the bearing, take your bearing holder piece and locate the two hexagonal cutouts in the bottom side. Those are for M2 nuts to press inside. They won't stay still firm enough just pressed into the plastic so you'll need to super glue them. The issue with super gluing nuts so small is that you don't want to get super glue into the threads. To do it correctly, take a single M2 nut and thread it onto a medium length bolt most of the way through but not enough to where the bolt is poking through the other side of the nut. Then apply some super glue onto any random surface you don't care about. Slowly rotate the nut around (by holding the button head of the bolt) carefully making contact with the super glue on multiple sides of the nut. Once you feel you've gotten enough glue on the sides of the nut, press it down into the little hole by holding the bolt. Make sure it's aligned nice and straight and finally unscrew the bolt from the nut. Repeat this process one more time for the nut on the other side! You can also take a soldering iron and weld inwards to make a little plastic lip seal around the outside of the nut which can be super effective at keeping it nice and firm. Be super careful not to melt too much if you do decide to do this! Keep in mind you can only use very short M2 bolts on these inserts and if you screw in too tight, they will pop the nuts out so be gentle!

The next thing I'd do is wire up your motor. To do this, just solder two wires onto each motor terminal (you can do this through the top of the motor body). Then thread the wires out the side hole and then through the conduit box. Once you've done that, you can press the conduit box onto the guide that's on the side of the motor body (you may need some super glue to firmly hold it on)

Take your motor body and your bearing holder and place the bearing holder (little flange side up) on the top (stator) portion of the motor body and it should hold itself right where it needs to be. The tricky part here is that you want the wire coming out of your conduit box to go straight down through the little hole in the bottom louver. In order to do this correctly, you'll need to temporarily bolt the bottom louver onto the bearing holder with those two M2 nuts you glued earlier. Then twist the louver-bearing holder against the motor body until the alignment looks like the wire will go straight down from the conduit box pipe all the way to the little hole in the bottom louver. Put a little bit of super glue on the top rim of the motor body (or the inside of the bearing holder) and finally glue them together! You can now remove the bottom louver you temporarily attached.

From here, slip one of the bearings around the rotor's shaft (which should be sticking through the bearing holder hole) and push it all the way down until it's pressed into the little hole inside the bearing holder. You can now spin up the rotor using the extended shaft. This is where you'll figure out if you have scraping issues or not. If it seems fine, then congratulations!

If you've made it this far, you've successfully done all the hard steps :)

Take your intake piece as well as the bottom louver and sandwich them underneath the bearing holder. The louver should be sandwiched between the intake portion and the bearing holder. With being gentle, thread two short M2 bolts through both the intake and then the louver all the way into the nut inserts in the bearing holder.

Take the fan and gently press it down onto the rotor shaft. Once it's in place, you can decide if you want to just leave it how it is or glue it in place just to be sure! (I just left mine how it was since the press-fit was more than tight enough)

The screen can be a bit tricky. The intake screen is as simple as just printing it and welding every little corner onto the underside of the stand.

The main wrap-around screen is printed in three sections that first all need to be welded together side-by-side to form a long screen strip.

With light strokes of the soldering iron, weld each connection from the top of the screen slowly around the 105's top hat. Once you completed the full circle, you should be able to slip over the screen ring and then weld it to the bottom of the screen-circle. 

Once you have the top hat/screen assembled, you can carefully slide it onto the top of the motor and bolt it on with three M2 nuts that should go through 3 M2 inserts in the top of the motor cover!

All that's left is to bolt it to the mounting plate and pick up a small eyebolt to thread into the top (I got mine from ACE Hardware) and your screamer-105 is complete!!

 Thank you so much for building or even just reading all of this description!!! I love to see what you all make with my files so if you do decide to build the 105, please either message me here on Printables, Discord, or tag me in a YouTube post!! I'd love to se how yours turned out :)