mech joint how to
I know most flickr builders won't require this kind of detailed description to figure this out, but I wrote it for MOCpages and it was easier to just copy here.
Here is the breakdown of the leg joints. Obviously, that section on the right slides on to the two black bars, and is pushed snugly into the holes in the technic bricks, with the dishes placed on last. There is another, identical section on the other side that is installed in the same fashion. The dishes are mainly aesthetic in nature and not necessary for the joint to function. On the bottom is a simplified breakdown of the pieces used in the actual joint. Of course, any length technic brick can be used and you can replace the 1x1 bricks with studs on two sides with ones with studs on four sides (Travis bricks) for some really interesting possibilities. I also see potential for this joint system for things like fold out wings on spacecraft etc.
Also, apparently LEGO makes two slightly different diameter 4L bars, since the black ones I am using here are significantly tighter than other colors I have tried, and add to the holding power of the joint. The looser fit of the smaller diameter bars still works fine, and could easily have supported a mech this size, but I wanted the centers of the hollow studs on the dishes to be black when the leg was assembled.
One word of warning however…this is a stud friction joint with quite a bit of holding power. It easily holds up this mech in any position, and could potentially support something a good deal larger. But since the joint is so tight, I imagine that over time there could be some issues with parts wear to the studs used in the joint and to the technic brick in the middle, especially when using the slightly larger diameter 4L bars. If you are simply displaying your MOCs as opposed to actively playing with them, I can’t imagine having any problems, and I myself have had no issues yet, but I just wanted to mention it before someone accuses me of conspiring to destroy their laygoes.
EDIT : As Crème-de-la-crème noted, you can do a reverse version of this with the 1x1 brick with side studs on the inside and the technic bricks on the outside. I actually tried that version when first building this mech, with the dishes flipped, slid on to the bars, and their studs inserted into the technic brick holes. This gives about the same holding power as the first version, and the reversed dishes are actually a little more greebly looking, but not quite as “realistic” looking as the outwardly curved version, IMO. But thanks for reminding me CDLC!