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Guides => Crow T. Robot => Topic started by: Oldeworldsmith on November 21, 2018, 12:31:47 PM

Title: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on November 21, 2018, 12:31:47 PM
I’d like to share my explorations of Netflix Crow’s new arms in the hopes of maybe stirring some thoughts and feedback. I’ve tried contacting some of the folks who bought the actual bot props as part of their Kickstarter rewards but have so far not had anyone get back to me about the measurements and attachment materials.

In the meantime, I’ve used the available promo images of Crow & Hampton Yont as well as several photos I took of Grant & Crow at this year’s Live Show to figure out some sizes. I used the known width/diameter of the foam insulation tubes (1.5”) to then scale-measure the rest of the arm rods and joint spacers. It’s not a perfect way of determining the sizes, but I think the consistent measurements that I did get via this method must be pretty close (within a quarter inch or less) if not spot-on.


What all the images in this post are about however, is in regards to the joint that joins the resin shoulder/lamp fixture to the arm assemblies. It’s clearly quite different than the multi-piece rod assemblies that were used with “classic” Crow. The ribbed rubber tubing now sits directly below the shoulder fixture which then gives way to the first of the lamp-arm, “triangle,” joint/bracers.

(Click the images for larger views)
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The other point to observe is how much free-range movement the arms now achieve when puppeteered. That means the connection from the shoulder to the arm cannot be hard connection like a bolt, as was used in the past, which only allowed for one angle of movement (back & forth). So that means we need a new flexible, yet sturdy attachment method. Of course, whatever that is, it’s being completely hidden by the ribbed tubing.

Still, I think I’ve come up a possible solution. I can’t say that this is how they’ve done it for the actual Crow puppets. I’ve no doubt the super-fancy new 3D printed part options and professional companies who are now throwing in for the construction of the props on the show have done something FAR cooler and engineering-worthy. But I have to say, what I kludged together WORKS, is super inexpensive, and it’s in spot that’s going to be hidden by that tubing anyway… So who cares? (Well still I do, but I’m very much satisfied with this for now)

As you can see in the photos, all I’ve done is create a semi-loose plastic loop that threads through both the resin shoulder hole and the lamp joint. I’ve done this by using the smallest zip-ties I could find (0.81” diameter), pulling them only so tight so that the top edge of the lamp joint (where the zip tie will always be visible) is pulled up into the ribbed tubing, where it remains hidden, just like the screen-used Crow.

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As you’ll see in the video link below, this allows me the same multi-directional range of motion we observe the Crow puppet’s arms performing on screen. It’s quite secure as well. My only concern is the potential wearing down of the resin shoulder hole where the zip-tie is threaded through over time, due to friction. But for a personal prop that won’t likely see any heavy-action performances, I think this is a pretty decent solution.
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on November 26, 2018, 12:08:53 PM
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Again, click the images for larger views

Over the Thanksgiving weekend and in-between eating & watching The Gauntlet, I was able to construct a fully operational Netflix Crow arm! I’ll post about the entire arm (parts & sizes) later on once I get a few more photos, but for now I’d like to address the MUCH BETTER shoulder joint connection I discovered!

Yet BEFORE that… I think we need to chat about the variations of shoulder joints that have appeared. Yep, that’s right, we already get a bevy of conflicting source material to work with that’s going to force us replica builders to start making choices based on what we think we like best.

First up, is what I’m going to call “Promo Crow”
Promo Crow primarily comes from the promotional images they took of him with Hampton Yont for Season 11. His distinctions include...

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-A classic, string operated jaw. This can be seen in several of the photos- Both under the jaw heading to the neck hole and with the old, BBI-style metal ring hanging out from the bottom of his PVC pipe; As opposed to the “string-less” servo-controlled jaw mechanism that’s used in the new on-screen puppet.

-He also is clearly lacking the puppet arm-control-rods that run up the forearms and attach to the wrist joint.

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-His shoulders are also clearly seen to feature the lamp joints sandwiched between two thinner spacers and bridged in-between by one wider spacer.

-The number of ribs on the black, ribbed rubber tubing is seven.

Yet, when we look at “Season 11 On-Screen Crow”

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-We find the spacer in between those same lamp joints are no longer broken up, but contain a single 1”-to-1.25” black nylon spacer- just like the rest of the spacers that appear throughout his arm structure.

This much larger width between the lamp joints made me believe that the ribbed rubber tubing used in Season 11 had to have a much larger inner diameter than the black, ribbed breathing tube we’ve all been using over the years, as you can see that the upper half of the lamp joints are tucked into the black tube. I can tell you the length between a fully spaced pair of those joints is 1.25” and the traditional black tubing is only 1.5” outer diameter with a 7/8” inner diameter. I did my best with the photos to determine if the S11 black tubing had a larger OD but it if that is the case, then it could only be less than a quarter inch larger. The black tubing would very noticeably protrude beyond the edge of the black shoulder block any larger than that- and it doesn't. Thus, the inner diameter must have been wider for this version.

-The number of ribs present on the black tubing is seven. The same number that are consistently on his neck in every variant.

With the pictures I took myself during the VIP photo session I noticed yet another variation in what shall henceforth be called, “Tour Crow”

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-Just want to point out that Tour Crow has the coolest control-mechanics of any version but we’re focused on the shoulders for now… Which have the same seven ribs on the black tubing.

-The “Promo Crow” spacer style is now back! The lamp joints are braced by two thin, outer spacers and one wide inner spacer.

And finally, while watching The Gauntlet I noticed a whole new change-up with, “Season 12 On-Screen Crow”

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-This one features a reduced black tubing that’s only five ribs high.

-The lamp joints are now spaced out in reverse: Two wider spacers on the sides and one thinner spacer in the middle! This makes the lamps joints slant into a distinctive “V” shape.

(Bonus: Sorry for having to take the screencap directly off the TV, but check out the giant washer/flat-metal-disc in Crow’s mouth attached to the servo-controlled jaw mech.)

So those are the variants I’ve spotted that everyone will want to consider when choosing what version of Netflix Crow they want to make. I’m sure more will appear as time goes on.

What that brings us to once more is how the black resin shoulder block is connected to the rest of the arm. I previously posted my quickie idea of using a zip-tie. That proved functional but not the most favorable as it could wear away at the resin over time. Something new started to consistently appear to me though in photos of all the different versions Crow…

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We see in photos that allow us to view the connection point at just the right angle, that there are protruding from the bottom of the black tubing, what I’ll simply call, “two bumps.” They appear between the upper lamp joints and seem to not be related to the straight, black spacers that horizontally span those joints everywhere else.

It hit me… Rubber O-Rings!!! Check it out:

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A good, sturdy, large rubber O-Ring (I used a #49 1 7/8” OD) slips right into the hole that already is present in the resin shoulder blocks we’ve all been using since Bob made them available. The fit is tight, and the rubber O-ring is hard to stretch past the ribbed rubber tubing, but with a little help from a bent paper clip you pull it out…
…To then loop both ends over the inner spacer of the lamp joints. I then used a standard nut to secure the bolt in place since the acorn nuts used on the rest of the arm would be too large to slide back up into the black tubing...

...And there you have it! Not only is it the perfect connection point which allows complete freedom of movement, it’s sturdier and softer than the zip-tie. PLUS, you can see the two loops made by the ring now give us those “two bumps” seen in the photos of the real Crow puppet!

So is that method confirmed? We still won’t know 100% until one of the team tells us. But I think this is a completely functional and (for what it’s worth) screen-accurate approach. I’m going to go with “Extremely Plausible.”
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: sledge_riprock on November 26, 2018, 04:32:04 PM
You are correct sir!  :D

Russ swapped out the old movable joints with O rings to give the arms more movement.

For the shoulders on the show Crows I used only 5 rings of the black tubing instead of 7. It might give you more room and make it easier to loop your O rings to the bolt.

Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on November 26, 2018, 08:20:26 PM
You are correct sir!

 :o :o :o

 ;D Thanks so much for that confirmation Bob! What an honor!
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Dr.cgad on November 27, 2018, 11:32:35 AM
Well I could use these at some point.
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on December 11, 2018, 02:57:17 PM
I wanted to share an update of where I’m at with the Netflix arms. I did a couple trial-runs with different lengths of arm dowels in order to test if my measuring method was accurate (which I will detail in a future post). I’ve finally settled on the what I confidentially believe to be the correct lengths which have successfully allowed me to recreate the same full range of motion and poses I’ve seen the real ones perform… Or at least as confident as I can be without being able to take a ruler to the real thing in person.

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I’m now in the middle of painting all the components and once that’s done, I’ll be sharing a full list of parts and measurements. But for now, I thought I’d share the method I worked out for wrists as they aren’t terribly complicated, but explaining them is going to be touch lengthy.

What’s obvious from watching the show is that a puppet rod now sneaks up through the open elbow area, into a sphere and then attaches to the enlarged fanny pincher hand. It allows for general movement of the forearm and also the rotation the hand as well. I’ve seen no evidence that the hands are articulated with an opening and closing “pincher style” mechanism. They are attached with what I would assume to be the standard Split Push-In Rivets which simply allow for the finger-half of the hand to freely hang and flop open & shut.

What that means for the wrist though is that the spheres which make them up must have at least one pivot point in relation to the rest of the arm, and also allow for rotation of the hands via a rod traveling straight through them. Again, I’m not saying I know for certain this was how it was done... But this way very much works, looks perfectly accurate from the outside, and I’d be quite shocked to find out they did something drastically different.

Using the comparative photo-measurement method, the wrist spheres appear to have a diameter of 1-3/4” which is consistent with the spacing between the rest of the joints. I found a batch of wooden spheres at a Hobby Lobby in just this size. Any larger (next standard size up is 2”) and it becomes obviously too big and no longer fits or matches the scale in relation to the rest of the assembly seen in the photos.

It can be very difficult if you’ve never drilled directly through the center of a sphere before. I’d absolutely recommend using a drill press as opposed to free-handing it. It will allow you to safely secure the shape and get a precision mark on the center point. It should also be noted these wooden sphere “beads” have a helpful way of finding their center points in that there will be two spots where, during their creation, they were held in a lathe and spun. Find them and use an awl to indent holes in them for your drills to sink accurately into.

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Drill this first hole completely through the sphere. The hole should be the same diameter of your puppet rod- just large enough to allow the rod to slip easily through and spin freely without friction.

Next, you’ll need to drill straight through the center again, but this time at a 90-degree right angle to the hole you just previously drilled for the puppet rod. This new hole will need to be large enough to admit two 8-32, ¾” length bolts. You can use a differently-sized gauge for the bolts if you please, but their length should not exceed ¾”

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As you can see in the dotted, red outlines I added, you don’t want them to go all the way through & meet in the middle. They should only go into the sphere deep enough to offer it a rotation point while not impedeing the puppet rod- which will occupy the center space. You should be able smoothly spin the sphere both on the rod and (separately) on the bolts and not have it wobble. If it does wobble from an uneven centrifugal force, that’s a sign you didn’t properly drill your holes directly through the center points on the sphere. Try, try again!

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The bolts will ultimately serve as the attachment points between the styrene joints. The puppet rod (seen in my photo with temporary shaft collars to keep it in place) will eventually attach to the resin pincher hands.

…Speaking of which, I’m also starting the process of enlarging a pair of the hands via the method I heard was used for the real-deals. Specifically, using an expanding resin. You can look up HydroSpan100 on Google for a full explanation and demo of how it works. In short, it will require a significant amount of time and several generations of re-molding to get them to their show size. We’re talking weeks to potentially months here actually and wouldn’t you know it… The company I bought the resin from sent me a batch that expires this coming April! So, wish me speedy luck. I’ve made silicone molds and cast resin many times before but this will be my first time attempting to work with the expanding variety.

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Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on December 12, 2018, 10:43:07 AM
Here’s a brief rundown on how to make the puppet arm-rods. I determined the rod itself from handle to the base of the hand is 20”. The method I’ve always seen puppet arm rods be built (and previously made myself) hasn’t changed much over the years and looking at the photos, they seem no different with Crow.

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Knowing that, I’m going to recommend buying & cutting yourself a pair of 1/8” steel rods at 22” to allow some working space in both the handle and the hand. Bend about a ¼” inch of one of the ends on each rod in a vice.

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Get yourself a length of 5/8” square wooden dowel. Cut two 5” length pieces and sand all the edges -both top, bottom, and sides- so that they are rounded enough to hold comfortably. Drill a 1/8” hole through the dead center of each dowel about an inch down from one of the ends.

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Use a Dremel to carve out a channel from the hole to the end of the dowel deep enough so that the bent ends of the rods can fit into the drilled hole and also sink into the channel just far enough to be below the surface of the dowel.


Use a two-part epoxy glue to fill in the channels and set the rods. Cover the tops of the rods with the epoxy as well and let it cure. The epoxy comes in different cure times based on what you choose. I prefer a 5 min. set times myself but it’s available in much quicker.

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Once that’s set, go ahead and paint them flat black. You can then also wrap the handles in Gaffers tape to make the grips even better for handling.

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And that’s it! You’re good to go on what’s probably the easiest and cheapest component of the Netflix arms.
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Dr.cgad on December 13, 2018, 01:13:48 PM
Pretty Nice.
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on December 13, 2018, 02:13:08 PM
Thanks! LOL

Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Zander Bricks on December 13, 2018, 09:22:37 PM
It's looking pretty good so far!  ;D ;D ;D
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on December 20, 2018, 09:56:43 PM
Soooo close to being 90% done! If only the accursed Metal Flake paint would dry faster on the final joints...

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Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on December 22, 2018, 02:59:56 PM
I’m about to post the measurements and materials I used to build these Netflix arms soon- I promise! But every recipe made to imitate another is always requiring taste-testing & refining in the kitchen before being served (how’s that for a metaphor?). I’ve been changing up a lot of the details and hardware on these things as I learn & observe more from new photos. I can’t promise they’ll ever 100% the same as the ones constructed by Puppetgarage, but I’m going to make sure they’re as darn close as I can get them (for being someone who only saw the real ones in person, in passing, at the Live Shows) before I commit to putting out my final parts list.

For now, I wanted to look at color. Specifically paint. Even more specifically, the color of paint used on Crow’s “Wrist Spheres.”

Here’s how my Netflix arms are looking after their first round of painting & re-assembly:

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I’m crazy happy with how these have come out! All except for one part. I’m not satisfied that the wrist spheres are matching what I see on screen and in photos. It’s clear they’re painted with a flat finish but what is harder to tell for certain, is if the somewhat grey shade they appear to be, is due to the way the light is being scattered across their flat finish or not.

Case in point, I painted them first Krylon Flat Black; the same Flat Black I’ve used on all the Crows I’ve built over the years. As you might be able to tell from the photos, that just doesn’t look quite right.

Have a look this photo of the screen-used Crow:

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Compare the shade of his Spheres to the the other parts of him that are clearly black. Parts such as his shoulders, neck and the drain tube in his chest. The Spheres have always looked to me to be just a few shades lighter and my first pass coloring my own has fully convinced me that the real ones couldn’t be plain ol’ Flat Black either.

The lighter shade they appear to be immediately made me think of a paint I’ve used many times before on other projects. Grey colored spray paint is available in spades… But not so many “shades” (see what I did there?)

I knew what I wanted to use this second time around is Rust-oleum Automotive Primer:

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Since this stuff is a Primer, it’s ultra-flat and is one of the only off-the-shelf paints on the market that’s a very, very dark grey. An almost-but-not-quite black color which is exactly what the real ones look like to my eye in photos. Since I would have to remove them again, I took a few photos that help demonstrate the method I devised to attach the Spheres to the wrist joints.

On the guitar-pick-like wrist joints, I have two holes drilled large enough to freely permit the 8-32 bolts I’m using throughout the arms to slide in easily. This allows for free ambulation of the arms when puppeteering. However I made the hole I drilled in the joint that accepts the shorter bolts for the Wrist Sphere smaller. Small enough to permit the bolt but not the threads, so that those two bolts must be threaded into the styrene joints with a screwdriver. This makes the joints hold the bolts firmly in place. The Spheres can then rotate and spin freely around the fixed bolts.

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After a couple coats of the Rust-oleum Primer, I think the results speak for themselves:

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Here’s the collection of colors I personally use both for old-school Crows and (with the addition of the Rust-oleum Primer) Netflix Crow:
-Krylon Semi-Gloss or Satin Black (your preference)- For the shoulders and Neck
-Rust-oleum Flat Black- For all interior parts of Crow; Inside the soap dish, Floraliers, etc.
-Rust-oleum Automotive Primer- For the Wrist Spheres
-Testors Metallic Gold- As a primer layer for the exterior gold parts
-Testors Gloss Custom Gold Metal Flake- for the final color of all Crow’s gold bits

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Now I’ve heard there’s some concern over the current Testors formula of what was once called, “Lime Gold Metal Flake.” The batch I’m using (renamed “Custom Gold”) is dated 2011 so I’m not completely sure if this is the newest batch everyone’s talking about or not. I find though that it doesn’t look any different, when enough coats are applied and dried compared to the oldest, original formula that I used on my first Crow back in the late 90s:

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But if anyone else knows of a reason why any Crow replica and the latest iteration of the Testors Gold Metal Flake paint should not be wed, I would ask that you please, not forever keep your peace and let me know!  ;)
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Ron on December 24, 2018, 02:31:08 PM
Nicely done, good sir!
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on December 31, 2018, 02:03:43 PM
I'm closing out 2018 with a body assembly and articulation test of the Netflix arms! Hit the link below for a video.

>> (<<

Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on January 18, 2019, 02:06:01 PM
I've been experiencing an unwanted but unavoidable delay in getting to Crow's new hands. So in the meantime, I think it's time I shared my specs for the arms so you can get started on them for yourselves if you're inclined to do so!

My method for determining the measurements came both from available photos of Crow found online, and from my own Live Tour photos where I was able to get better profile angles on them. What you do is scale the image of a ruler to an object of known size nearest in proximity to the unknown-sized part you want to measure. In this case, the known parts were the lamp joints and more easily, the diameter of the cylindrical foam insulation tubes. Once the ruler is scaled and consistently giving you the correct measurement of the in-hand, real-world object in multiple areas of the photo, it's time to use it to measure the unknown parts. Here's a screen grab to give you an idea of how that works:

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I cross-referenced those with other images of Crow and found the results consistent. Could they still be slightly off? I'm afraid that in using this method, one can never say with 100% surety these measurements are flawless. It's not a good way of getting tiny, specific results. For example, determining smaller fractions like 1/8"s or 1/16"s. But since I find these bots have rarely used fractioned measurements lower than 1/4" in the scratch-fabricated parts of their construction in the past, I feel fairly confident in these findings. My Netflix arms look pretty dang spot-on to me. Plus all the found parts that have to work in conjunction with the pieces I fabricated from raw materials also worked together perfectly.

So without further blabbering, here's my recipe for the Netflix arms with corresponding item description:


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NOTE: This is a list of pieces required for ONE arm alone. All listed quantities must be doubled to make TWO arms.

ALSO: This recipe will give you the parts to make arms that are in the configuration of "Tour Crow" and "Promo Crow" which I chose as my personal favorite to replicate. See my second post in this thread for specifics on what makes them different from the other observed variations which you may find you prefer instead.

A.   Two sections of foam insulation tubing cut to 3.5”
B.   Two sections of foam insulation tubing cut to 4.5”
C.   Six Round 30mm Nylon Spacers (originally 1-1/4” in length) sanded down to 1-3/16”
D.   Three Round 30mm Nylon Spacers cut to 3/8” in length
E.   Four Round 30mm Nylon Spacers cut to ¼” in length
F.   Two standard 8-32 black nylon washers (30mm OD)
G.   Three 8-32, ¾” length bolts (unaltered length)
H.   Two 8-32 bolts custom cut to 2-1/8” in length
I.   Six 8-32, bolts custom cut to 2-3/8” in length
J.   Two 3/8” Square wooden dowels cut to 7-1/2” in length
K.   Two 3/8” Square wooden dowels cut to 7” in length
L.   Four 3/8” Square wooden dowels cut to 6” in length
M.   Resin cast lamp housing “shoulder” from Sledge Riprock’s eBay parts store
N.   1-¾” Diameter wooden sphere (sometimes simply labeled as a 'bead')
O.   Regular Crow-style ribbed rubber tubing (cut to 7 or 5 ribs, depending on your version preference)
P.   1-3/4” x 1-9/16” x 3/32” #38 rubber O-Ring
Q.   Eight 8-32 “Nyloc” aka Nylon Insert Lock nuts
R.   One 8-32 Hex Nut
S.   Pair of “upper shoulder” lamp joints (original metal, resin re-casts or styrene replicas)
T.   Pair of “elbow” lamp joints (original metal, resin re-casts or styrene replicas)
U.   Pair of custom, styrene “wrist” joints*

* Holes drilled in the styrene which will brace the wrist spheres must be smaller than the 3/8” bolts so that said bolts can be securely threaded into them vs. the other holes that will be drilled out larger to allow the longer 3/8” bolts to loosely slide into them. I personally recommend fabricating your own styrene versions as opposed to the resin ones as they will be much stronger and less prone to cracking when you thread the bolts in and out of them repeatedly during construction.

I have also been able to determine the measurements and parts for making Crow's new Netflix legs. I'd like to put them to the test in prototype form first though to make sure they're working and look correct. Happy building!
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith 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.

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(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:

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

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- 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.

Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on February 15, 2019, 01:02:57 PM
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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.

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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"

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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.

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Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on February 25, 2019, 12:23:18 PM
It’s been a wild week! But I’m so much closer to shaking hands with Crow than ever before. Which has to be much better than “Shaking Hands With Danger.” <<That’s a Rifftrax reference BTW. Hopefully they’re allowed here.

I set about casting the fanny pincher claws and beginning my first foray into experimenting with HydroSpan resin in the effort to enlarge them. I’m going to recklessly assume most folks here are already familiar with the creation of silicone molds and the resin casting process so I won’t waste time typing out a full, lengthy explanation of it here. You can always search for “Smooth-On” on YouTube for a ton of videos that illustrate the steps & methods better than I could relate them anyway.

The only thing of note is the preparation of the thumb/wrist half of claw- The wrist portion needs to be reduced & shortened as Netflix Crow’s wrist clearly terminates at the wooden sphere at a point closer to the rest of the hand then the original claw permits. The wooden peg you see added is the portion that will insert into the sphere after enlargement.

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This was also the first time in many, many years I can finally say that I had to use complex math outside of grade school. The HydroSpan resin has a mix ratio of 100A:50B by weight. That requires you to do a formula based on how many grams of part A you’ll be mixing to determine how many grams of part B you’ll need to mix as the catalyst. Thank God there was a video demonstrating how to work that formula on YouTube as well. Take THAT, 12th grade algebra!

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The results? HydroSpan when mixed turned out to have a viscous consistency, much like honey. Which, if you’ve worked with resins before, you’ll know is a bit thicker than the usual fare. To ensure success, I created and utilized what are called “squish molds” as opposed to the more common type where you would sculpt a “pouring-spout” into the silicone for TWO REASONS <<Hey! Another Rifftrax reference!

1.  The thick, uncured HydroSpan is unlikely to ooze its way all the way down into every corner it needs to via a pouring-spout method
2.  The claws parts are both very thin-walled. Any time you have parts that don’t have ample thickness, using a squish mold is better as it allows you to pour the resin into an open-face half of the mold and then set the negative on top, ensuring an even spread of material into the nooks & crannies of your casting. Here’s a video of what I’m talking about just in case that sounded confusing: (

I now actually believe this to be the same stuff that is used to make novelty water-enlargement toys like these: (

Once that cured, I discovered the HydroSpan did not become fully rigid and stayed rubbery. This made trimming the flashing away from the parts a little difficult but aside from that, the casting was successful. The next step in the instructions are to submerge the parts in water for up to ten days to reach the full 60% enlargement.

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I was shocked when I checked back in only 48 hours and discovered they were already at what has to be full size!!! It appears that the thinnest sections absorb the water fastest. As you can see in the photos, the denser portion of the wrist is still smaller than it should be while the thinner walls of the “thumb” exploded in scale overnight. I’ll still let the whole thing soak for a full ten days regardless.

Unfortunately, the next big challenge presented itself pretty bluntly the moment I touched the enlarged parts. Due to these parts being so thin-walled and the HydroSpan material being so soft, they and now super rubbery and can’t hold their proper shape worth a darn.

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I don’t think there’s any way I can recast these parts to make a new silicone mold of them and not have that process fail miserably. There’s no way I could ensure the wet, slippery parts don’t float off into the silicone while it cures or guaranteeing the parts maintain a consistent and non-warped shape.

A possible solution? I figure if the enlargements of thin parts won’t hold their shape, then perhaps enlargements of the thick ones (i.e. the molds that produced them) will.

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So back on the chemical mixing merry-go-round I go! Once the castings of the molds get “big-ified” in the water, I’ll have to make yet another set of silicone molds of those before I can attempt a standard resin casting of the larger claws… I have to say this is getting really expensive, but I learned a long time ago if you can’t embrace that fact, BotBuilding isn’t the hobby for you.
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on March 08, 2019, 11:23:20 AM
It's been 10 days soaking the Hydrospan castings in water and... They're still not quite there yet. It's become quite clear to me that the denser and thicker the casting is, the longer it will have to soak before growing to it's full capacity. Likewise, thinner and less-dense parts will achieve their full scale in less time. As you can see in the following photos, the individually cast claw parts have fully grown to the full size of the Netflix Crow hands. Regrettably they remain unsuitable to re-cast due to their overly soft & rubbery nature which renders them unable to hold their proper shapes in the process. The castings of the molds are holding their shapes properly as anticipated but you can see when I take them out of the water, they're still puckered in spots that have yet to fully absorb the water.

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Comparing them to the full-grown claw castings also shows me how much more they have to grow to catch up.

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I suppose I also have to consider the possibility that something may have gone wrong when I cast the molds. Maybe I screwed up the math required to figure out the ratio of A to B mix in the Hydrospan. But for now, I'm going wait several more days and see if the water absorption continues to enlarge them properly. It's hard waiting but that just gives me more time to focus on building the rest Netflix Crow so there'll actually be something to go with his hands...

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Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: minermark on March 14, 2019, 11:12:34 PM
Been reading and following your current Crow project, well done sir !
Read up on this HydroSpan material, very interesting and dam handy it seems.
I would be most interested in resin cast copys of this current Crow, please keep me in mind, id like to help you off-set some of your cost of your R&D.
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Dr.cgad on March 18, 2019, 10:53:35 AM
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on March 18, 2019, 11:18:48 AM
Been reading and following your current Crow project, well done sir !
Read up on this HydroSpan material, very interesting and dam handy it seems.
I would be most interested in resin cast copys of this current Crow, please keep me in mind, id like to help you off-set some of your cost of your R&D.
Thank you very much! I'll certainly keep you in mind. Let's just keep our fingers crossed that I can successfully achieve a decent set of enlarged resin hands when all's said and done.

Speaking of which, here's the progress report:

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The molds continue to grow measurably! It's been 19 days since they started their soak and they've been gaining in scale every day. You'll see in the photos, on the right-most side, is a set of the molds I made which weren't mixed as well as they should have been, thus I didn't attempt enlarging them. They've proven useful however as baselines to measure against the growing copies. Also useful have been the cast set of claw parts (left-most side) which allow me to see how much further the molds need to still expand before they're ready for silicone recasting. Based on the progress I'm observing, I'm going to estimate it'll probably still be around another two to three weeks before they're finished. 

:'( Deeeep waiting! Deeeeeeeeeeeeep waiting!

In news unrelated to Crow's arms but still relevant to Netflix Crow in general, I've been fortunate to discover for the first time what I'm going to call the "SledgeRiprock Method" or "Bob Method" of Crow building. Having built my Crow years ago, long before Bob started making and selling his Bot kits, I'd actually never seen or sought out to learn how he managed construction of the inner PVC pipe controls. I just implemented my own method based on the knowledge the bot building community had at the time.

Thankfully, someone shared with me the instructions Bob includes with his Crow kits and it's been a Rosetta Stone (Crow-setta Stone?) for figuring out the rest Netflix Crow. As we've known, they've gone to Bob for parts just like the rest of us and have clearly been assembling their on-screen bots using his construction guidelines too- Which I have to admit now that I've seen them for the first time, are really super simple and effective! I'm sure everyone is reading that and saying, "Duh, yeah. We know."
Hey, cut an old-timer some slack!

The one thing I've been taking my time on is making sure I compare measurements of the PVC sections given in the Crow kit instructions to photo references from the show. Now, I fully believe that every Crow, even those made for the show, are all slightly different. But I did find some sight discrepancies in the lengths of piping that make up the neck and the stalk on which the soap dish is perched to what the recommended length is in those instructions. That's NOT a criticism, mind you! Just an observation based on photo-matching. We've already confirmed Russ made a number of alterations to Bob's initial designs, even though all evidence points to the fact he's still using the same basic method in the PVC pipe controls. But in order to match the best average of what I'm seeing for Netflix Crow in screengrabs and press photos, both lengths of PVC pipe that make up the upper portion of those controls need to be slightly shorter by around a 1/4" to a 1/2".

Again, I don't believe the Crow in the following press photo to be the "one-and-only" standard for his construction. But I've chosen it as my own personal standard to match and you can see what that's given me:

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I can only recommend you to look closely at the photos and do what feels & looks best to you! I can take the neck measurements that I wound up settling on and post them if anyone's interested. In the meantime, I'll continue to focus on the arms.
Title: Re: Netflix Crow's Arms & Shoulder Joints
Post by: Oldeworldsmith on March 27, 2019, 01:56:50 PM
Day 28. The mold castings are still at only 70% or so of what I know they can enlarge to. Something's got to be wrong.

My first plan of attack: Relocate the Hydrospan parts to a spot where I can add an electric fish tank heater. It's recommended the water stay around 70 degrees for proper absorption. Maybe my water's been too cold.

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If that's unsuccessful, it looks like I'll have to see if I can devote some of this month's paycheck to buying another round of Hydrospan and trying again. Maybe I messed up the A to B chemical mix. I might also try a suggestion I found online that recommends inserting plastic rods into the backside of the uncured hydrospan as it sits in the mold. Once removed, that should allow channels to form in the denser areas into which water can more easily penetrate later on.

What would be really be helpful would be knowing exactly what size & scale the real Netflix Crow's hands were grown to. ...Would anyone have a chance to hit the Atlanta puppetry museum with a ruler and get me those measurements? LOL ;D  :'(