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Welding hydraulic cylinder rods

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D1005

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#1
I'm working on a project that involves a couple of these cylinders in an 1800 PSI max system:

I9fBDTe.jpg

All of that extra rod makes them too long to fit in the space available. From what I've learned so far, extend the rod all the way to the end, cut the rod to desired length, protect with duct tape/wet rags, and weld on a new end. Ditto on the base end.

I've always thought the rods were hardened, but apparently just the chrome surface for the seals is.

Am I on the right track?
 

Tony Wells

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#2
They are heat treated to be tough, not really hard, and the chrome provides the wear protection. It can be quite thick, and I doubt your bandsaw will like it. The last time I had to cut some, I ground through the chrome with an angle grinder, then hit the bandsaw. An abrasive chop saw will cut it. You should grind the chrome back away from your weld zone. But generally, yes you are on the right track.
 

dlane

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#3
Welcome, “ditto” on the base dose that mean your welding on that also
 

firestopper

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#4
You might want to bevel the weld joint and weld it hot. Are you stick or Mig welding?
 

machPete99

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#5
I need to do something similar at some point. A trick that I read about is to bore and thread the end of the rod and do the same on the cross tube, where they are to join. Then use a section of mild steel threaded rod or cutoff mild bolt to hold them together. That just positions everything while you fire up the welder. Use mild steel in case someone wants to saw it off in the future.
 

Chipper5783

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#6
Hydraulic cylinder rods? They are not all the same. They are supposed to be induction hardened and chrome plated (good ones are). Some are not chromed, some are not hardened (some might even be stainless).

I reworked some John Deere rods. They were chromed. I simply purchased some cylinder rod material from a hydraulics shop. The hardened layer was about 0.07" thick (I presume it was induction hardened, but perhaps it was hardened by another process?). On the piston end, the step was quite small, so the threads were mostly in the hardened layer (I used a brazed carbide threading tool and sharpened it about 6 times). For the outer end, I cut the eye off the old cylinder - I don't remember how, but it wasn't much of an issue (band saw, abrasive saw or a torch - the metal is going to give). I machined a small locating pin and bevel on the end of the rod. I cleaned up the eye and machined a mating pocket & bevel. I poured my best "bubble gum" into the bevel (probably just 7018) - machined it up all pretty. That was nearly 10 years ago - I bet it is still working fine.

A cut & weld, as you have proposed would work fine. If you have any concern or challenges with the welding - cut the piston end off. Shouldering and re-threading the piston end is very straight forward.

For the base end, wouldn't you just cut the ears off, shorten them (or make new ones) and weld them back on? Why mess with the wet rags - just take the cylinder apart, fix it up and put it back together. Then you can be sure that you won't damage the seals.

You did not mention what kind of equipment you are working with. The approach to take really depends on what tools you have available.
 

FOMOGO

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#7
Definitely doable. Like Paco said V it out well, and if available, I'd stick weld it for good penetration, 7018 or similar. Mike
 

eugene13

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#8
WEAR A RESPIRATOR WHEN YOU WELD OR GRIND ON CHROME. The heat will release hexavailant chrome, AKA chrome-6, a known carcinogen and some really bad stuff.
 

D1005

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#9
Thanks for all the replies!

To answer some of your questions/comments, they are cheap, surplus cylinders, so I doubt they are anything beyond the common and, well, cheap.

The base end is far longer than it has to be, so I'm looking to shorten that end as well, looking at it again yesterday, I may be able to simply drill new holes in the existing ears, leaving them in place. If not, some cutting, grinding, and welding will be required on that end as well. If so, I'll probably change it to a tab mount to simplify matters.

For cutting, I recently added a cheap 4x6 bandsaw, which cuts straight, to the chop saw that cuts crooked, and angle grinders with cutting blades.

Welding is predominantly stick. I have a cheap flux core, wire feed, but it provides very little in the way of penetration. I'd like to convert it to DC operation, which appears to help based on another thread here, as well as other places, or may just look for a "better" cheap wire feed. An honest to goodness MIG, with real capabilities would be nice, but it's not in the budget. As is a long list of other machines required to be a "machinist". For me, machining is grinding and filing.

The project is a grader blade under my sub-compact tractor. I've had one under a garden tractor years, and for grading, a true grader blade can't be matched. Unfortunately, disabilities are preventing me from using this older tractor, I had to switch to a different tractor with a different style operator platform. I've regretted from day 2 not getting the next larger series, as there is so little clearance under this one, hence the need for very short overall length cylinders, while maintaining some stroke. The cylinders will be lift cylinders on the pull stroke, so the maximum they'll have to pull is 100 pounds or so each, push will provide some down pressure as the never recommended standing on the blade is no longer possible.

Dang, that got long, I tend to do that once I get going.....
 
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firestopper

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#10
Like FOMOGO suggested, 7018 SMAW GMAW will do a nice job for you application and performed outdoors. Keep a wet rag over the gland nut but don't quench your weld. My .2
Thanks brino, only got 4 hours of sleep last night.
 
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Kernbigo

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#12
why weld it like someone else said cut off the piston end and re thread it , a lot simpler
 

firestopper

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#13
why weld it like someone else said cut off the piston end and re thread it , a lot simpler
Although this would work great, it would in no way be simpler and take much longer vs cutting, beveling and welding. This could be done in under an hour x2. In fact he's probably already done with them.;)
 

D1005

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#14
I appreciate your positiveness, Firestopper, but I'm notoriously slow, especially this time of year. I spend a few months doing research waiting for it to warm up enough to venture outside again.

I thought about opening the cylinder up, but one little nick in a seal, and I'm dead in the water. Plus, a new hole would have to be drilled freehand and I don't know exactly how precise that hole needs to be drilled. Lastly, a different end on the rod may be of benefit in my case, which means cutting and welding anyway, so why not do the shortening at the same time? I bought the surplus cylinders on price and stroke, not proper ends. I thought I could allow for the extra rod length, but that just didn't pan out, so variation #2 on design, well, more like #10. :boxed in:

All suggestions are appreciated, but there are always a slew of factors involved that would take a book to list them all. I'm sure anyone who's ever built anything knows what I mean. :encourage:
 

Tony Wells

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#15
Haven't seen it mentioned (or missed it) but if this is a welded cylinder it's time consuming to cut off an end and remove the piston/rod assembly just to get to the threaded end of the rod. Then you get to remachine one rod end, and prep the end you cut off and the cylinder for welding it back together. Far simpler to cut and reweld the connection.
 
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