1 of 9

Open Source Hydraulic Cylinder

​

  • The Hydraulic Motor is part of the GVCS
  • Hydraulic cylinders are linear hydraulic actuator
  • The hydraulic cylinder for the CEB Press is not easy to source
  • Cylinder has a 2.5” shaft and needs to stick out further than typical cylinders because we use a 2.5” sleeve around our cylinder

DIY scenario:

  • Take a plain cylinder with stub rod (not likely to be 3.5” sticking out
  • Take out the rod from any longer cylinder, and replace the shorter rod with the longer rod
  • If rod is 2.5”, and cylinder is 8” - the rod simply has to fit.

Sample Picture

Credits + License:

2 of 9

Modules of a Simple Hydraulic Cylinder

​

Cap end

Honed Tubing

End Cap

Piston

Rod

Rod End with seals and wiper + seat for tubing

Fitting

Fitting

3 of 9

Requirement

​

Cap end

Honed Tubing

End Cap

Piston with seals for 3000 PSI

Rod

Rod End with seals and wiper + seat for tubing

Fitting

¾” NPT

female

Fitting

¾” NPT female

Grade 8 Rod with threaded ends

3.5” of rod

sticking out

Nut + Lock Washer

4 of 9

Requirements

​

Cylinder Specification:

  1. Cylinder working max pressure - 3000PSI
  2. Bore: 5” cylinder
  3. Stroke: 8”
  4. Rod: 2.5”
  5. Rod is sufficiently long such that a minimum of 3.5” are sticking out of the finished cylinder in the retracted rod position
  6. Rod has no end - it is just cut off.
  7. Overall width of the cylinder is 6” or less (it has to fit within a 6” wide space)
  8. Cylinder has 4 tie rods
  9. Rod end + end cap are square with 4 tie rods
  10. Tie rods are ⅝” diameter (or whatever is sufficient to provide 3000PSI working max strength)
  11. There is a seal between honed tubing and end cap, and between honed tubing and rod end
  12. The end cap has nothing on it (we will put on mounts ourselves)

I am requesting parts to make cylinders

  1. 300 lb of honed cylinder tubing for the cylinder specified below
  2. Rod with threaded end for piston, piston, piston nut, rod end, end cap - all the internal parts to make 5 cylinders
  3. Tie rods, nuts, and washers - parts to make 5 cylinders
  4. Please provide parts that are common and easy to soure, such as standard seals, wipers, and rings. Please make this so that it is as easy as possible to find and replace parts.

5 of 9

Detail + Design Rationale

​

Credits + License:

Press Foot Bottom Plate

2.5”x4” DOM, 2.5” long (¾” wall)

1” space

Cylinder tops out at

Press Foot Bottom Plate

Press Foot Top Plate

  • Rod must stick out 3.5”
  • 2 plates are used such that shimming can be applied to correct for level surface of press foot
  • Shimming can also adjust for height - up to 1” of adjustment if needed
  • 1” space prevents seal from being punched out if rocks or dirt get under DOM

6 of 9

Top View of Press Foot

​

Credits + License:

2.5”

4”

4”x10”

6”x12”

¾” Hex Nut welded to 6x12 plate

Plate is torch heated and quenched in water. Scratch test it afterwards.

1-¼” Hole - torched if no punch or mag drill

7 of 9

Fabrication

​

Option 1: weld top of cylinder rod to sides of DOM

Preferred option: grind down top of cylinder rod, weld into the chamfer to attach to the sides of the DOM

Exactly 3.5” of cylinder rod must be sticking out of cylinder.

8 of 9

Bottom Attachment of Cylinder

​

1”x2” DOM, ½” wall

9 of 9

Detail + Design Rationale

​

Credits + License:

1” plate

2.5”x4” DOM, 2.5” long (¾” wall)

1” space

This configuration doesn’t work because rod needs to top out at the press foot.

​

This design would have been nice because rod could be welded easily to the DOM - no grinding of shaft required

Press Foot