Terminator T-800 Blueprints

Another, hopefully more refined version of a dust plug, side view, sliced. This would be a side access point for installing a pin thru the elbow sections of the arm.
 

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Conqueror_Worm;

Metacarpals proving to be a tricky cut, especially based off the drawings. There are a couple of missing numbers. Illustration shows which ones.
 

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The knuckles were believed to have been welded long 'after' production. At some point a previous owner (thinking it of little value) probably just welded it into a open pose since numerous parts were missing. It was clearly manufactured and intended to be articulated. The L.D. restoration is simply putting it back, "as new."

QUOTE: Okay, so the LucasDesigns site with the beveled holes where the metacarpals attach there are some things about that that rub my fur backwards. First off, he is "restoring" a movie prop. Looking closely, the knuckles were "welded" if you can call that, so that they didn't articulate and he ground off the blobs to make it articulate.
 
Rylo;

Do you think all machined Terminator wrist plates had beveled machine-screws holding the metacarpals in place? Do you think they were welded as well? Because of failing links, see Conqueror_Worm's illustrations and photos. The hand looks welded at the metacarpals with grinder-shaping at the base.
 
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Your links don't work, but if you want to PM me a photo with the parts you have in question 'circled' I'll let you know what I think.

By the way: There are more than two mechanical arms out there and they're all different. Again, as I get some time, I'll get more into that on a thread of my own design. I do not want to pull this one off track.

Thanks

So Rylo you think those beveled cap screw under the metacarpals is part of the regular design? I ask this because I'm at that stage in my build and I'm getting to a point when I'm going to have to connect these parts together somehow. I was planning originally to weld them together because of this image here -

View attachment 225215


Or this image here -

View attachment 225216


Both original screen used movie arms, both look articulating and mechanically complete, for sure the second one, both showing no seam between the metacarpals and the wrist plate, and both possessing enough extra metal at the base of the metacarpals to appear to have been welded and then the weld ground to an organic shape mimicking natural human metacarpals. Those LD images are the first I've ever seen of the bottom of the wrist plate and those horrible aluminum "brazings" looked wrong. I get that it was designed to articulate. My impression was that every version of the Terminator arm came from a functioning, articulating, cabled design but each version included only the elements required for it's scene. That's my impression so I attributed any variance to that idea. I could be wrong. But if you're certain that the cap screws under the wrist plate are nom de riguer, then that settles it. That does refer me back to that extra metal at the bases of the metacarpals. It doesn't look machined, more like sculpted by grinder. Is that weld? Post attachment metal that has been shaped? or is it an optical illusion?
 
The metacarpal dimensions aren't missing, you just have to do a little math to get them. ;) My drafting professor always stressed that you should never over dimension your drawings.
If I were going to make one, I would start with a piece 9/16" x 9/32" x 3 1/16". Turn it on a lathe, off center in a four jaw chuck, to create the 5/16 diameter round portion. Mill the slot and the radius at the top. Drill and tap the top hole. Lastly, fabricate the side lug separately and braze it on.
I guess I'm still not entirely clear on your elbow design, would you mind drawing your design over top of my drawings? That way I will know exactly where your pieces are, and how they relate to the other pieces.
 
The metacarpal dimensions aren't missing, you just have to do a little math to get them. ;) My drafting professor always stressed that you should never over dimension your drawings.
If I were going to make one, I would start with a piece 9/16" x 9/32" x 3 1/16". Turn it on a lathe, off center in a four jaw chuck, to create the 5/16 diameter round portion. Mill the slot and the radius at the top. Drill and tap the top hole. Lastly, fabricate the side lug separately and braze it on.
I guess I'm still not entirely clear on your elbow design, would you mind drawing your design over top of my drawings? That way I will know exactly where your pieces are, and how they relate to the other pieces.

Yep, thats how I made mine. I need to get off my ass and finish that thing:)
 
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[quote="Conqueror_Worm, post: 3029520"]The metacarpal dimensions aren't missing, you just have to do a little math to get them.   My drafting professor always stressed that you should never over dimension your drawings.
If I were going to make one, I would start with a piece 9/16" x 9/32" x 3 1/16".  Turn it on a lathe, off center in a four jaw chuck, to create the 5/16 diameter round portion.  Mill the slot and the radius at the top.  Drill and tap the top hole.  Lastly, fabricate the side lug separately and braze it on.
I guess I'm still not entirely clear on your elbow design, would you mind drawing your design over top of my drawings?  That way I will know exactly where your pieces are, and how they relate to the other pieces.[/QUOTE]

Conqueror_Worm;

I just attempted to make the metacarpal by turning a chuck-centered aluminum bar that was 3/4 square. Doesn't work. You get the finger mounting tab but not the cable mounting tab. The off-center lathe thing is the next experiment except I hate off-center turning because it's really easy to screw up if the work isn't chucked exactly correct. It's like trying to make a crankshaft out of billet. Also, it seems to me (but I won't know until I try it) that a 5/8 square bar will do the trick with .0015 extra on both dimensions, at least that's how it looks when I dyekem dye the top and scrawl it out on the end of the bar. I get both the finger-mount point and the cable tab without having to weld any tabs on. It is all one piece. Also your drawing shows two flat sides on the dimension which measures .281. I think if you off-set the bar so that one corner of the bar becomes the rod of metacarpal under the tabs after turning, the flat spots automatically form if you cut the rod to be the dimension of .311. It knocks the outer corner off and the inside is also round but the back side stays flat. At least that's how my dyekem measurements seem to be working out. We'll find out once I cut it. I broke my parting tool and there is no local source for mini-lathe tools here in San Diego. Waiting on the replacement.

On a second topic, the lumbrical pistons I think can be made to be air-springs by taking advantage of a natural vacuum that occurs, negating the need to try and stuff a spring into a 1/8 inch hole. I stumbled onto that idea when trying to make little-bitty pistons out of brass and flange the bottom for that ball point pen spring idea I had. To keep from bending the piston shaft, I took a block of mild steel and drilled an 1/8 inch hole, the same dimension of the brass rod, with the intention of inserting the rod into the hole and then carefully peening a flare onto the end. What happened was I destroyed the piston trying to get it out of the block of steel because it had such a vacuum that the rod refused to be pulled out without vice grips. I repeated this experiment enough times that I wasted a foot of brass rod trying to make a spring-loaded piston at one-inch at a time. I took a second look at the photos of those things and noticed they look like miniature versions of a pneumatic cylinder I have on my desk, right down to the inlets, if you look at the set-screws as inlets. I'm thinking now of drilling a 1/8 inch hole all the way thru a quarter-inch diameter rod of stainless steel, bore one end to .155 for the Du-bro clevis, slide the piston in with no vacuum resistance, set the length as needed then the set-screws and the Du-Bro for the seal to make a vacuum. The real question is will it be strong enough to hold a vacuum but not too strong that it loses a spring effect like my little pneumatic cylinder on my desk has when you plug the inlets. If it works, it simplifies that part of the build. I'll keep you posted.

Also did your software give you any dimensions for those single-helix torsion springs you drew for the joint-returns? There is some math there, like wire thickness, inner-diameter, outer-diameter, leg length and of course tension in Lb's. Obviously this affects the fingers' ability to return to straight, but also there is a depth to be cut inside the knuckle to compensate for the wire, plus if the loop is too small, the legs don't rest against the flat-spots inside the knuckle and if too large a diameter, there needs to either be a larger diameter joint pin or more realistically, a shoulder on the side of the pulley to keep the spring centered so the joint doesn't bind. I've found a couple sources for torsion springs but they all need those dimensions. Did your software happen to work that out? What you drew looks really good and functional.

Update on above lumbrical pistons: Just noticed the Du-bro 303 clevis has an opening between the tines of the fork. Not air tight. One may have to solder in some of the Du-bro connecting rod into the hole to seal it. I'm trying to make the hand and arm functional, not just pose able. So far the pistons, the wrist plate and the spade bolts are easy and straight forward. With the pistons, getting a smooth bore is important for functionality. The drill bit used seems to make a big difference. Look for a bit with flutes longer than 1.66 in length. When cutting the longest piston, a shorter flute length causes the aluminum (or whatever material you're using) to get jammed up in the bore, scoring the inside of the bore. Also, I'm told, even though the bore is 1/8 inch (.125), stepping up with smaller bits till you get to .125 will yield smoother results.
 
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I haven't done any math on the springs. The parts I drew were just to help convey my idea. I'm not entirely sure that's how they did it, it seems difficult to find springs that are that strong and that small.
I can't wait to see what you come up with for the pistons. As for the clevis not making it air tight, you could leave a little material between the piston and clevis areas when you are boring it out, making it two separate cavities. I know this contradicts what I just said, but if the boring is too tricky, you could always buy some tubing that is .25 OD, .125 ID. McMaster-Carr has some, but it is $40 a foot!
 
https://dl.dropboxusercontent.com/u...ence/T3 Arm/OriginalEndoArm3LowResVersion.jpg

High rez finger picture from page 3

Conqueror_Worm;

I've been studying this pic blown up on my desk. It has amazing close-up detail that I think holds many manufacturing answers. My lumbrical piston looks pretty good, just like this pic in fact, but doesn't function as an air spring as I had planned. I think to do that I need to make it more like a syringe which means a close tolerance. As to your idea of having an internal spring, so far the smallest diameter spring I've been able to find is .165 +-, thicker than the Du-bro clevis at .151. Looking at the pic, I notice the "pistons" are all retracted even though the fingers are splayed into differing positions. BUT the Du-bros are in differing amounts of contraction and it makes me wonder if we're looking at the wrong end as the moving end. Maybe it's the Du-bros that extend or contract and how would that affect the internals? As to the torsion springs in the fingers, I cannot visualize any other way. I think your version is it. Sometimes, I think I see gaps between the joints in the pic that would allow for the spring, specifically look at the thumb joint and the first knuckle of the forefinger. It's clearly stepped inside the joint making room for a spring. Regardless, I think your idea is best, but making these parts really illuminates the limitations. I'll get my piston pic up for you to see. I just received my Mcmaster-Carr shipment today for those set screws and once assembled I'll throw it up as an example of a dynamite static piece. It looks great with that stainless rod coming out of the top.

One change to your plans I'm making is how the metacarpals are attached. The LucasDesigns pics really got me thinking about the use of the beveled screws and beveled holes for the metacarpals. The beveled holes will allow for a couple degrees of change in the angle of the metacarpals to adjust for all the geometry happening with all the cable pulls and pistons and such. I cannot see any reason why not drilling a shallow hole on the bottom of each metacarpal and attaching them with the same phil flat FT MS 18-8 screw stainless 8-32X3/8 screw that holds the wrist plate to the forearm pieces, which by-the-way is still fuzzy in the drawings. You got the screws in the plate but no corresponding holes in the balls on the other side of the plate, or so I couldn't detect. Anyway, after the hand is assembled, as per the above pic, the metacarpals can be welded in place. Those McMaster-Carr screws come in a box of 100 so there are plenty available. And they're stainless! Which is pretty.
 
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For the torsion springs, check out Lee Springs. BUT there is some math required and that affects the strength of the spring-tension.

Also, there is a generic speedometer cable that can be purchased at Pep Boys or Kragen Auto Parts (I'll research the brand) for the thumb rotator and possibly the palmer pistons but I haven't fooled with one yet, only heard about it as a modeling tool for the resin model. Same source for a small piece of brake line for the hose in the forearm, same brand as the speedo cable. I'll try to nail down the brand.
 
Conqueror_Worm;

Okay hopefully RPF will allow these images of my Lumbrical Piston Assembly. This is what I had originally hoped for- a spring loaded retracting piston to off-set the force of the lateral cables that makes the fingers wag. From a manufacturing point of view, it seemed to me the most logical assembly was that of a ball-point pen. The tolerances are tight keeping authentic to the original look and physical specs. I wasn't sure it could be done but I've succeeded and here's my proof.


This first pic is all six parts.

Lindgren Lumbrical Piston Parts.jpg

This second pic is a pre-assembly of the parts. The set screws are lightly attached to the piston cylinder, the spring goes over the piston and the Du-bro clevis lays at the ready.

Lindgren Lumbrical Piston PreAssy.jpg


The third pic is the completed Lumbrical Piston. It is spring loaded and constantly retracts into itself. The piston and spring assembly are installed from the bottom, the Du-bro end, and the Du-bro clevis is the cap that holds everything inside the mechanism. I made the piston long enough so that it protrudes when the Du-bro clevis is inserted. The set screws hold the Du-bro in place keeping the piston from flying out of the bottom and the upper set screw basically adds a little resistance to the piston taking up any lateral play.


Lindgren Lumbrical Piston.jpg

It works good. I haven't tapped the hole in the end of the piston. Also this was a "quickie" so the quality isn't what I'd like but as an experiment it proved educational.

Here's a breakdown of the dimensions:

Cylinder length is 1.68
Ends of the cylinder are .250
Middle of cylinder is .181
Top bore is .125
Bottom bore all the way up to top shoulder (depth of 1.375) is .155
Base of piston (spring flange) is .151
Shaft of piston is .118
Length of piston is +- 1.50
Set screws are 1/16 with pitch of 4-40
Du-bro clevis is threaded at fork, one side 4-40, no thread inside.
Du-bro diameter is .151
Industrial Compression Spring Length is 1.33
Industrial Compression Spring inner diameter is .125
Industrial Compression Spring outer diameter is .151

Materials used are:

Cylinder = aluminum
Piston = Stainless Steel
Spring = Spring steel

* a note on the spring; a ball-point pen spring has too large an outer diameter for the cylinder. They run about .175 O.D. That tolerance will leave .003 of metal in the cylinder wall (of my cylinder above), the thickness of the average human hair.
 
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Wow, nice! That turned out really well. How much travel does the piston have?
The Lee Spring site looks good, but I'm really not sure how to determine a suitable torque value. Have you seen this image? The slots look really narrow, maybe less than 1/16". I would guess the spring can't have more than 3 turns. Also, any idea what the circled feature in the top right corner of the image is?
Jamie Staff made his own cables, here is a video of his technique.
 
Conqueror_Worm;

As I go down the road with this project, I'm finding that I need to make some modifications to your designs to suit my build. As I am not interested in taking credit for the design, can I get permission to change your original designs to suit my needs and still give you credit for the original drawings? Some examples of what I am talking about are the spring-loaded lumbrical pistons, and now the various ball joints and forearm piston rod end pieces in the wrist which will lead to some changes in the wrist plate. Visually they take on the appearance of your design and are based on your measurements but there are some functional differences, for example both the Dorsal and the Ventral (should be Lateral) Wrist Ball Joints become two pieces each which includes a ball stud and a spacer/lock nut instead of one piece. I don't want to entirely redesign what you've done, just make some mods to accommodate found objects while retaining your original appearances and I want to make sure you're cool with it. I'd like to post the results, giving you credit for the original work while simultaneously showing the changes I made to get the result. Are you okay with that?
 

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