MAKE A PISTON AND CYLINDER

[Chariots of Fire]

In the "In Progress" section of trucks there is a posting of a great scratch built project for a yard truck.  Bob indicated he might have to redo his hydraulics to make a piston that would not come out of the cylinder when he raised the 5th wheel up.  Below is a tutorial of how you can make such using ordinary materials.  I have made these successfully using aluminum for the piston because it can be polished and brass tubing for the cylinder parts.  But as you can see in the tutorial it can be made with plastic tubing as well so long as it will telescope with the aluminum tubing.  

Here is the first photo with the materials needed and a description of how to do the assembly.

In the photo above are the three materials for the construction and a small section of plastic rod to be used to make sure the piston and plastic sleeve do not come apart inside when all is said and done.  I've labelled the stock to be used but the sizes are not important so long as they telescope freely and are not sloppy.

To the right side is a cylinder with a section of plastic tubing inserted inside to act as a sleeve for the piston to slide inside of.  Use only a small sliver.  On the outside is a piece of plastic stock that on the real cylinder would be the raised portion of the housing.  Also shown is a disc of plastic stock.  This will be used to seal the far end of the cylinder. Adjacent to the cylinder is the piston that will be inserted into the cylinder from the right end.  It has a sleeve on the outside the same diameter as the sleeve that is inside the left end of the cylinder.

 

In photo 2 I have inserted the piston into the cylinder with the free end of the piston protruding at the right and the sleeved end of the piston showing at left.  You can see the piece of plastic rod inside the piston.  I drilled a hole straight through the sleeve and aluminum piston and glued in the pin.  After glue sets the pin can be cut smooth with the surface of the sleeve. The pin keeps the sleeve from sliding on the piston in case the glue separates.   The sleeve is a thin slice as you can see from the first photo.

Photo 3  With the pinned sleeve in place insert the piston into the cylinder from the end opposite the one that has the sleeve inside.  Since the sleeve in the cylinder and the one on the piston are the same diameter and just fits into the cylinder it allows the piston to move without a lot of wobble.  Be sure that the glue on the sleeve on both cylinder and piston is completely set before inserting the piston or it may become permanently glued so it cannot move.

The piston is extended its full length inside the cylinder and the sleeve on the piston is touching the sleeve on the cylinder.  This is how the piston is kept from coming out and is shown when the piston is in the fully extended position.   With the piston on the inside of the cylinder, the cylinder can be sealed with the plastic disk.

In the fourth photo the piston is drawn into the cylinder with the piston sleeve backed up against the closed end of the cylinder.  Again, be sure that the glue surrounding the end plate is dry or you may get glue on the sleeve which will prevent it from sliding.  With this part of the project complete appropriate pieces can be added to the cylinder where it would be attached to say the truck frame and on the piston a piece of plastic tubing could be inserted inside with another piece glued at right angles to form the end that attaches to the equipment to be raised.

What I have shown is generic in that I have not made an attempt to size the cylinder or piston.  That has to be done according to each application.  But the trick is to have an inner sleeve for the cylinder and an outer sleeve for the piston that are the same diameter and that telescope well.  If you use brass tubing for the cylinder you may have to double up some additional pieces to get the proper thickness for the piston to slide through.  And the same thing would be true for the sleeve on the piston that slides inside the cylinder.  but the process is the same.

I added a photo of my Coleman truck with the body raised so that you can see a finished piston and cylinder that was constructed of aluminum and brass tubing.

I hope this has been of interest to those who may have wanted to add this kind of detail to your model.  SBIF! (Scratch building is fun)

 

Charlie

(Chariots of Fire)

 

Edited November 30, 2018 by Chariots of Fire

[Ace-Garageguy]

NICE !!! This is the kind of stuff that's the real value of user contributions. Thanks.  

[hct728(Bob)]

Seems simple enough, I had to use a sleeve anyways to get the I.D. down to the piston size, and never thought of this tweak! Thanks Charles!

[GLMFAA1]

A simple system is to secure thread/string inside the cylinders the length of the stretch, the string stops the cylinders before they come apart and doesn't interfere with the operations of the cylinder.

greg

 

[Darren B]

Super sweet tutorial. really love tutorials like this. thank you for sharing.....