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Working hydraulics


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#1 skulls

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Posted 18 January 2012 - 05:48 AM

I am just wondering if anyone might know a way to make some sort of functional hydraulic rams, just bacically somthing that can be positionable but strong enough to stabilize some weight. I am looking to see if I can scratch build a car carrier trailer in the near future and well with all the hydraulic rams they have on those trailers I want to do the same but maybe make them strong enough to be positionable and still hold the weight of a car model on them.

Thanks
james

#2 cavejohnson

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Posted 18 January 2012 - 09:28 AM

Hmm. I did a small replacement ram on a die cast auto transport that was 1/25th. I used some aluminum hobby tube (I guessed the size). As for making it positionable I stuffed a bit of Mystik No.2 high temp grease in the tube and that created a nice substitute.

#3 cavejohnson

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Posted 18 January 2012 - 09:31 AM

I guess I should add that my setup used what looked like a piston. So when you extended it, it allowed grease to move into the bottom of the tube for support, when it was compressed it made a bit of back pressure but after a couple of seconds it would stablize.

Edited by cavejohnson, 18 January 2012 - 09:31 AM.


#4 Tony Bryan

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Posted 18 January 2012 - 01:05 PM

To have working rams is relatively easy, and to have them hold weight is also easy, here is what I have done in the past
I machine the piston of the ram just a fraction smaller than the inside diameter of the cylinder than I require, then I insert a pin on each side these are then filed down to suit the
cylinder, so they are a tight fit, the ram then relies on fiction to work, with some fine tuning you can get them very close to being what you want and hold the weight that you want it to hold
I have made them in styrene tube, and used a drill to shape what I want them to be, (hold the parts in the chuck

here is the pin that is filed down ready for a test fit, you can also machine a groove and use "O" rings as you are applying friction to the inside of the rams/cylinder

Posted Image
Posted Image

Here is some better ones that I had some white metal fitting made these did hold a 600mm boom up
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The grease option sounds like it would be ok, but could end up messy, then again, would add some real detail, good idea there,
the radio antenna, so also a great idea, but these create a lot of force on the fittings that you attach, and on the model when you are adjusting them as they are tight, the antenna has to stay up right, and are generally chrome, which is a hard surface to get glue to stay attached to


The RC guys have full working hydraulics, with pumps, valve banks, and rams, they are expensive


Hope this helps

#5 skulls

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Posted 19 January 2012 - 05:29 AM

Wow, thank you so much guys for the input. Tony those rams you made look amazing, and just like everything else in this hobby, it looks like it will take a bit of time and alot more patience.

#6 cavejohnson

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Posted 19 January 2012 - 10:25 AM

My setup looked a lot like Tony's, except I don't have any means to make a precise friction piston. I did have both ends sealed up and after 2 years it still works and no grease has escaped. I use that No. 2 to grease fifth wheels and then spray it to create a crust of sorts so it doesn't make a mess.

#7 skulls

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Posted 26 January 2012 - 05:32 AM

I think I will give it a try, nows its just a matter of going to pick up some stock at the hobby shop.
Again "cavejohnson" that is a really great idea with the grease, I will give it a shot and it should hold
the weight that I need on it.

#8 Truck parts

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Posted 02 February 2012 - 07:00 PM

The rams look great

#9 ewaskew

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Posted 03 February 2012 - 01:48 PM

On real car hauler's the main support beam that the cylinder's push up and down have hole's in them.
Once you have the ramp where you want it you stick the safety pin in one of those hole's and let the cylinder down until the pin
bottom's out.
If you do this on your model it adds detail and you don't take a chance on the cylinder's not holding the weight.

#10 skysoldier46

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Posted 16 November 2012 - 06:59 AM

I did a scratchbuilt well drilling rig that has working hydraulics for the drill tower. It's in one of the threads here, I didn't use any grease for effects tho but the tower does raise and lower with no problems.