Author Topic: Netflix Crow's Arms & Shoulder Joints  (Read 562 times)


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Re: Netflix Crow's Arms & Shoulder Joints
« Reply #15 on: February 08, 2019, 03:25:14 PM »
Cool news update! For anyone who wasn't aware, the Atlanta Center for Puppetry Arts inducted the Crow & Servo puppets into their collection this past January.

(Photos by Gary Glover)

Just a few days ago, Brent Lohaus posted new, super close-up images of the bots to the "MST3K & ICWXP Bot and Prop Builders" group on Facebook!

What's especially exciting for me is discovering that the details I've (so far) only been guessing at with the Netflix arms... Has been totally correct!  :D ;D 8) Both in materials and in the methods of assembly and ambulation!

Most importantly, Brent was able to get a photo that revealed the never-before-seen (by fans at least) area behind Crow's wrist sphere- specifically the spot where the puppet rod enters the wrist sphere from behind.

First is Brent's photo and then second is my own:

You can see what holds the rod in place from behind is indeed a shaft collar! Like these:

It prevents the rod, once secured into the resin claw hand, from being pushed out of the wrist sphere from behind. It still allows, via the set screw within the collar, for you to take apart the whole assembly for repair or replacement.


More of Brent's photos give us other cool details that we can see up-close for the first time!

- There's a screw in the back of the neck coupling that descends from under the bowling pin. I have to guess it's possibly for the ability to quickly switch out Crow heads should one become damaged. Or in the Nextflix case, should the servo-actuated jaw stop working.

- We can see the model in the museum is that very same type of remote-operated jaw version as there's electric cables emerging from the bottom of the PVC pipe where the eye controls mount.

- In that same photo we can see that the dowel rods attached to the arm rods are round. I've made a previous post where I demonstrated making them using square dowels. It's always up to the puppeteers personal preference. Many do prefer round as it allows for the rod to be easily rolled back and forth between finger and thumb with minimal effort of hand movement. I'll be certainly making a new pair with round dowels now!

- Lastly, it looks like many of the joints feature washers both inside and outside of the various attachment points.

I tried doing this on my own arms but ran into a problem. They may seem very thin, but washers add significant millimeters to the width of those arms. It all adds up quickly and throws off the sizing. Plus, I had never seen a photo of a screen-used Crow that was detailed enough to 100% confirm there were indeed washers present. At least now we can put that suspicion to rest. What this tells me now, is that the black spacers in-between the joints and possibly even the screws that are inside them, may indeed not be stock-sized. I already had them figured for slight alteration in lengths but it looks like that alteration could be even more significant than I thought.

You see, it's all based on the side-by-side foam insulation tubes and the wrist sphere. Those items dictate a fixed width between the dowels, joints and spacers. I'll have to look again at what needs to be done to resize those later elements while allowing for the extra inclusion of all those washers.

« Last Edit: February 08, 2019, 03:30:57 PM by Oldeworldsmith »


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Re: Netflix Crow's Arms & Shoulder Joints
« Reply #16 on: February 15, 2019, 01:02:57 PM »

Having re-circled the wagons, I've now come to a new crossroads in regards to scales and sizes of certain element in the arms. I bought the new smaller sized hardware and reconstructed the arms based on the configuration seen in the ACPA photos I shared above.

I'm now confident in the following changes to the Netflix arm recipe (again, based on the known measurement of the square dowel rods being 3/8"):

-The spacers in between the arms are thinner than I previously had used and are now 5/16" in diameter
-The spacer lengths (and uniform space between the square dowels) are either 1" long or 1-1/8" long. This may seem like a small difference but it adds up in a huge way in regards to the size of another part which I will detail in full further on...
-The size of the machine screws and lock nuts used are now 6-32
-There are 22 #6 washers used throughout the build of one arm
-The machine screw lengths would ideally be 2-1/4" but to date, I haven't found any sold in that length for that gauge. That length must then be achieved via cutting longer screws (in the case of those pictured, 2-1/2") down to preference. A shorter 2" screw WILL NOT work for either possible width configuration. I tried them.

Due to my uncertainty in the exact length of the black nylon spacers, but now fully confident in the configuration of screws, nuts, washers, dowels and lamp joints, I have found that the precise diameter of the wrist sphere is what subsequently gets thrown into question.

I built one arm using the 1-1/8" spacers and the other using the 1"

You can see by the photos that if the 1" spacer is the right size, then the 1-3/4" sphere fits perfectly between the styrene wrist joints (no nylon washers required). If instead the 1-1/8" spacer is the correct size to use, then the gap between wrist joints is now much too large for the smaller sphere- However the next size up, a 2" sphere, now fits perfectly between the joints.

So what to do? Both look okay to me just by eye. What I believe will help break the tie is seeing what a full-sized set of enlarged grabber-claw hands look like in comparison to each sphere. To achieve a set of those means these arms are now on complete hold and it's time to get cracking on the molding and casting of the hands with the expanding resin.

« Last Edit: February 15, 2019, 01:19:14 PM by Oldeworldsmith »