how to shorten a hydraulic cylinder

[accordionman]

HELLO TO ALL,
does anybody here know how, or have you reworked a
hydraulic cylinder? i need a procedure in order to do this.
i need step, by step. i have a welded cylinder, that i want
to use for top, and tilt (2), but these need to be shortened.
i have the machines, and the ability, but do not know how to
proceed. any help, greatly appreciated. thanks.
accordionman
wlbrown
wright city, mo.

 

[rswyan]

This thread by Henro ought to provide some insight:

http://www.tractorbynet.com/forums/customization/44732-never-ending-t-t-path.html

 

[3RRL]

If you have the means and ablity it's not that hard to do. You can check the cylinder "O" rings and seals while you're at it and replace if required.

1) Dis-assemble the cylinder.
2) Pull out the rod plunger with cylinder cap still on it.
3) Measure housing OAL and lip that seals against "O" ring in cap.
4) Lathe down the housing to desired length & re-cut threads.
5) Re -create lip seal as before so it fits cap. (deburr & polish)
6) Re-install rod, plunger and cap.
7) Cut off shaft to new length.
8) Weld on swivel ball end to shortened rod.

I think I got it all? When welding. be sure to extend rod all the way out and keep the shaft
and cylinder body cooled off by wrapping wet towels or something around them.

 

[dfkrug]

I just completed a shortening project for a new Kioti CK20 hyd toplink.
I wanted a 7" stroke and a closed length of 17". Ends had to be
cat 1 swivel balls. I bought a Grizzley tie rod cylinder from AgriSupply for
$60, cut the cylinder and the rod, welded on the swivel ends and
had exactly what I wanted. If you have a welded cylinder, cutting the
barrel of the cylinder will require re-threading the end cap. Or cutting
snap ring slots, if that is what it uses. The tie rod cyls are cheap and
and the cast end caps require no special machining. Shortening the
tie rods was the hardest part, believe-it-or-not. The cyl rod is 1.125"
hardened steel and has to be cut with torch, plasma, or abrasive wheel.
Total cost of this project was about $110 for cyl, swivels, hoses, QDs,
and adapters. Labor at $.001/hr.

 

[accordionman]

3RRL,
SIR,
recut the threads? i thought a welded cylinder did not
have threads. have not taken these apart yet, but the
rod end has a snap ring to remove the piston, and rod.
i am sure you know more than i do about these, as i have
seen some of your work. the rebuild of the box blade in a
previous post. that was a great job. i will try to keep in
touch with you if this is ok, as i may have some difficult
questions later on.
accordionman
wlbrown
wright city, mo.

 

[3RRL]

Not knowing what kind of welded cylinder you had...sorry, just assumed they were all alike. Nevertheless, the process is the same, requiring you to re-make the attachment on the housing to match the cap. I have seen some that were threaded...or was that my grease gun housing?
BTW, you can use a 1/32" cut off wheel on the surface grinder to zip through those rods...hardened or not. Hold the rod in a large "V" block or precision vise, block it in so it don't move and clamp to the magnetic chuck.
Otherwise, check the hardness on an area you're going to chop off with a single cut file. If it cuts, you can saw it. If the file skids, it's hard. I checked mine just recently and sawed the threads off...they were soft.

 

[markct]

heres the thread that shows how i did it

http://www.tractorbynet.com/forums/build-yourself/23673-homemade-hydraulic-toplink.html

i later found out from talking with the guy from the hydraulics shop that this is the way they usualy do it also since the base end is alot more forgiving of slight misalignment than the gland end. i did use the lathe to clean up some parts for welding but thats not a requirement. i coulda done it all with a angle grinder, welder and saw if i had to

 

[3RRL]

Good job on that thread Mark, I had not seen that before...made it look easy.

 

[dfkrug]

A good point was made that the rods are sometimes only
hardened on the surface (chrome plated). When I have that
kind, I grind off the chrome and use the bandsaw to cut. Otherwise
I cut the rod with the plasma cutter. I did not check to see if
the threaded area was hard. It makes sense that it is not, Rob.

I noticed that my cheapo tie rod 2500 psi-rated Grizzley cylinder
has 3/16" thick walls. Very thick. What were you guys seeing
as cyl wall thickness on your cylinders?

 

[3RRL]

Dave,
I didn't measure the last one I did but as recall from my failing memory 3/16" is pretty standard.