Metal ball joints for 1/3 scale action figure?

Hi All,

First of all, I'm a complete none metal working modeller. Metal work at school was never my strong point! So I'm not sure if I'm allowed to be here or ask advice, so I apologise in advance if I've broken any rules.

Anyway, I was wondering if anyone could help me with a problem I have fixing a Japanese 1/3 scale anime figure.

The doll is a high quality 66cm silicone model with a metal skeleton. It can be posed in any position, and in order to do this the skeleton has bendable joints at the correct locations with stiff stainless steel 'bones'.

The joints however are made of bendable metal which over time has become weak. One knee joint has broken and the other is close to doing so.

I don't want to replace these joints with the same bendable metal only to break again in a few months. For the same reasons, I'm not wanting to use plastic either. So, I was wondering if a ball and socket type joint is available that is tight enough for the figure to free stand, but be bendable enough to be able to pose the the doll?

I've looked around the web and found ball and socket joints, and universal joints, but they are too large for my requirements, and have too much range of movement. I need a joint that behaves just like a human knee joint with a 160 or so degree of bend, with no side to side movement.

The joint would also need to be 8mm or so in diameter so that it could sleeve into the existing metal chin and thigh bone. As far as I can tell, this type of joint simply does not exist to buy, and I hoped that someone here could point me in the right direction to someone who might be able to make these for me?

Any helps appreciated!

Jim.

This looks a good place to start, Jim **LINK**

https://www.animationtoolkit.co.uk/6mm-double-pro-ball-joint/

MichaelG.

Ah, never saw this site! Thank's Michael!

I thought that I would just point out that you only require a hinge for a knee joint, not a ball joint.

Maurice

.

Very true

... but it would be a simple matter to constrain the movement of the item that I linked.

MichaelG.

Edited By Michael Gilligan on 10/03/2019 00:37:29

I think Michaels idea would work, the only problem being that the thigh and chin "bones" are both solid metal, so the screw rod of that kit wouldn't be able to screw into them.

I think I would either have to cut further up/down the leg to see if I could see if it is hollow tube further in, or I'd have to find a hollow sleeve to go over both pieces? To be honest I'm not happy having to expose any more of the skeleton as the silicone will probably be a bugger to try and re-seam later on. :s

The "wire" you currently have in there is called Animation Wire and available in many sizes. It's often used to make a support for sculpting figures in clay. Ray Harryhausen would machine his own armatures which did consist of ball and socket joints and they're not too difficult to make. It's been about ten years since my last animation armature as CGI has almost completely taken over but the principles remain the same. I can't even remember what the advert was for but it featured a number of characters including a wooden bird living in a dolls house.

You would need a ball joint (or animation wire) at the hip and ankle though not only to allow for the foot to meet the ground in a flat manner but also so the leg and ankle can twist.

One of the original King Kong armatures that sold at Christie's about ten years ago. Note the knees are ball joints but they include a pin running through them so they only act as a hinge.

Edited By Chris Trice on 10/03/2019 03:16:18

Could you take an unwanted Action Man and cut above and below the joint, then drill the plastic to take the ends of your rods and glue them in. Elbow would do if the knee were too large.

.

I think 'Action Man' would be a little undersized, Jason

Quote from James's opening post:

"... a Japanese 1/3 scale anime figure.

The doll is a high quality 66cm silicone model with a metal skeleton."

MichaelG.

I know nothing about Animation but those ball joints look like they could be useful in other ME applications - and not too expensive either...

Regards,

IanT

It's worth looking at how the original Action Man figures joints were articulated, with a combination of hinges and swivels they give realistic articulation with lass complexity than ball joints.

Action man is flesh size so the joints would be about right for the bone of a figure twice the height and just about right for the 8mm wireframe and allow the silicon skin to go back in place.

It also sounds like James has very limited tool so the plastic could easily be sawn and drilled with average DIY kit

Edited By JasonB on 10/03/2019 10:13:46

Thanks for the really varied answers and suggestions guy's, I never expected such a wide response!

The joint from a plastic action man idea I'm not going to consider though. The figure itself isn't a toy, it cost nearly £800 and weights the better part of 4kgs, so all the joints particularly in the legs, are taking quite a considerable load.

To be honest for something of such quality I'm amazed they used such apparently cheap wire to construct the joints in the first place! (not very Japanese!)

So, I'm determined that if I'm going to repair it properly I want to use metal, and I only ever want to go in there once! I'm ok with it costing more, so long as I've got a good permanent repair that's going to be the correct size and shape, as anything too bulky will obviously destroy the look of the leg.

So far I'm looking at contacting Michael's suggested people at the animation toolkit site as these look like really good joints.

I'm still open to suggestions though as I want to get this repair right.

Jim.

The Action Man idea is no good because you can't adjust the friction of the joint. There's always a screw immediately above or below the ball that can be tightened or loosened, or on occasion completely locked. The ball is usually sandwiched between two plates.

You might be able to scavenge bits from one of these:

**LINK**

They work just like King Kong...

I apologise for returning to this thread after such a long interval, but an idea came to me while in the workshop earlier today. On a shelf I have a couple of tools for smoothing fillets made of "Plastic padding". They consist of 4" lengths of !/4" brass rod, with various sizes of hardened steel ball soldered into depressions in each end. I have found that the balls take soft solder quite readily. I picked one up, found a suitably sized thick steel washer with a chamfered hole, and one of those impossibly strong magnets that was about the same diameter as the washer. Magnet, washer, ball ended rod, stick them together in a line.....a ball joint. It stays where you put it and moves smoothly when you want it to. A pole face made of iron would probably be better, and perhaps a seating for the ball that matched its radius rather than a cone. Just those few bits assembled in a hurry seemed to work so well, that I thought it worth posting. I may even experiment myself, just out of interest.

Regards Maurice

Hi Maurice,

I'll just smile blankly, nod and stare straight ahead looking like I know exactly what you're talkng about! Thank's for revisiting this post, I'm still considering contacting a company Michael suggested as up to now it seems the way to go. I'm back at work this week so I've got no chance to sort this out at the moment.

However, your idea sound's amazingly like a proper knee joint in theory...I think?!! But would it scale down to the tiny size needed, while still being strong enough to support around 4kgs in weight?

This is the space that it would have to go into! The two metal rods are 8mm in diameter and the space between them is about 35mm. I couldn't remove the old (bendable) wire as it's been crimped in I guess some way further up the leg and I don't want to cut any more silicone for fear of never getting it back to shape. So if the joint was to fit it would have to fit over the metal rods.

If you do experiment I'd be very interested in seeing the results..... even if I don't understand how you did it!!

Thanks again, Jim.

Hi James; I'm sorry but I do not think this idea would be suitable for your particular needs, but when I tried it and it worked first go, I thought it worth sharing. My first thought other than your good self, was for making possible figures for artists or perhaps amateur animation enthusiasts; if there are any. I think there must be. Best of luck with your endeavours.

Regards Maurice.