I was moving logs. Broke into 4 pieces.
I'm thinking it was just tired, or had a slight bend to it. Induction hardened obviously and they shatter like that. Sadness.
clean off the ends and post a close in view of the cross section, could have been a defect in the material.
Was the stick ever used to pound on something?
**** material. Should only be hardened 10-20% of the cross
I've never seen an induction hardened rod that didn't shatter like that when bent or overloaded, although typically only in one spot. I'm thinking that one must have had some fractures, possibly from a former owner trying to straighten out a slight bend, or just a slight bend giving up.
Good news its a pretty cheap fix, a hydraulic shop will weld your eye onto a new chrome shaft and turn the far end to match your piston, done in a couple hours.
I don't know about poor material. This is a low hour M series grader ripper cylinder that got a rock jammed behind the barrel. It's certainly not the first Cat rod I've seen break when bent by a only small amount. On the other hand, I've seen rods on "cheap" machinery, (farm implements, trucks, trailers etc) bent like a stick of spanish.
See in the one pic how the cylinder is pointing up? When I bought it it had a bolt holding some pipes down and it dug into the cylinder. Guess it bent the piston each time it moved out. I cut it off, and used it about 6-8 hours since but the damage was done
Those are also some boogery welds on the end of the boom, where that plating is, might be signs of more previous damage. I've changed out a few rods on the Kubota, thankfully Kubota uses buttery soft steel in their fabrication and everyplace else. Even drilling and tapping is a pleasure.
I'm not sure. I have handled Sennebogen, Liebherr, Rexroth mill cylinders that have up 1/8" bend and are straightened to go back on the job. Good portion of bucket cylinders are bent and don't shatter. Seems like bad spec to me. The 1050 plated shafting I usually deal with is only .020-.030 and on bigger cylinders no more than 10% of the cross. Almost as hard as carbide. But maybe these are bad.... hard to the bone? LOL
And if original, 40 years old!!!!!!!!!! LOL
As long as it wasn't retracted than an extension attempt was made you'll be in pretty good shape
We snapped a cylinder off in the same spot on a new (under 500 hours) 931 Cat trackloader with a tree shear on it years ago when a piece of hardwood limb got caught in between the boom and ram while cutting.
Was there any external forces placed on the cylinder? Maybe logs pushing against the arm inwards? Once you get the cylinder replaced i'd get the overload relief valves for the arm circuit checked and adjusted.
Is that something I can do? The machine is 1 hour from civilization
Before you fix it, check for excessive play in the joint from the boom to the stick. If there is a lot of movement there, it can fatigue the rod and lead to a break like you have. If that is the case, repair the loose joint or the repaired rod will suffer the same fate. It is also possible, like mentioned above, that something got between the barrel and the boom.
Any chance the cylinder is too long for the machine?
I will check the bushing. I don’t remember a lot just from using it. Quite possible. Don't know what the boom and stick is off of but it's not original
The reason I ask is that normally the cyl bottoms out before the implement travel limit is reached. If the cyl had a longer throw, boy, that'd raise hell wouldn't it?
Ouch... Hydraulic cylinders are pretty simple devices. By design, the polish rod goes in and it goes out. It is not a load bearing device but rather a simple push/pull device. The weight of the piston and polish rods is all on the seals and fiber bushings and that is all they can hold. All fractures break perpendicular to their load and looking at the pictures and nature of fracture, the load was not down the length of the cylinder but literally across it. Metal is predictable, ductile (soft) bends, brittle (hard) breaks. Looking at the shear lip, the load was above the rod. Said simply - It was smacked royally. Not sure what you hit to shatter the rod in four places but it too should be walking with a limp.... Cheers!