LEGO hydraulics

[Ras_Al_Ghul]

I am working on a bulldozer MOC, and I am wondering: does anyone know of a place where I can get some hydraulic/pneumatic cylinders that will work with LEGO for a reasonable price? BTW I've had other people that I should just use two official LEGO cylinders end-to-end, and there is no possible way that will work - it's a 1:7 scale model. Yes, I am seriously building a 5-foot long working dozer.

Thanks for any ideas.

Ras_Al_Ghul

[Front]

First of all check this discussion Hydraulics

If you want something to lift with hydraulic cylinders, I would guess you would need a pump (electric driven, maybe by a Lego motor) hoses and the actual cylinders. I have no idea how small you could get hydraulic components, but I suspect most hydraulics are way bigger in dimensions than what you need for your 5 feet dozer.

There are pheumatic Lego components, but I'm not sure that they can be used for lifting stuff at the dimensions you speak off.

Anyway, very interesting MOC you are working on. Keep us updated on your progress

Front

[CP5670]

You would probably be better off doing this using motors and gearing, maybe with a thread/pulley mechanism to actually lift the blade so you don't run the risk of breaking pieces. A couple of PF XL or 9V red/black motors geared down enough should be powerful enough.

As for third party pieces, look at fischertechnik's line and see if they have anything useful. I vaguely remember reading once that their pneumatic system was compatible with the Lego one and had some extra features.

I think a bigger problem is what to use for the treads. I suppose you could just use several 8275 tracks side by side to make them look thick enough, but you would need something much larger than the usual sprocket wheels.

First of all check this discussion Hydraulics

As mentioned there, those things don't have anything in common with actual hydraulic pistons and wouldn't be appropriate for this at all.

[Ras_Al_Ghul]

I have already tried using gears, and none of the several prototypes I've built have worked. They're all either not nearly strong enough or too big. I have found a website that makes custom cylinders that I could get to work with LEGO, but they start at $150 each - I will need 8. As for the treads, they were one of the easiest parts. I found a guy on Brickshelf that built some large scale treads for his construction MOC's, and I built wheels for them out of a bunch of click hinges.

[Brickthus]

I have already tried using gears, and none of the several prototypes I've built have worked. They're all either not nearly strong enough or too big. I have found a website that makes custom cylinders that I could get to work with LEGO, but they start at $150 each - I will need 8. As for the treads, they were one of the easiest parts. I found a guy on Brickshelf that built some large scale treads for his construction MOC's, and I built wheels for them out of a bunch of click hinges.

What are the requirements for the girth and the extended and contracted lengths of the cylinders?

Mark

[Ras_Al_Ghul]

What are the requirements for the girth and the extended and contracted lengths of the cylinders?

Mark

I would like it to be 8 studs across, and the outer shell about 40 studs long or so. I want the inner part to move as much as possible. Got any ideas?