Bending pin on hydraulic cylinder

[TroyC]

I read a post yesterday and it was mentioned by someone that they spaced a hydraulic cylinder with washers and bent the pin. It was a regular contributor so I hope it gets seen here.

I bent my bucket cylinder rams a couple months ago. Dealer ordered cylinders under warranty, who knows when they will get here. As a back-up to get things going while waiting for the originals, I ordered a couple replacements. My originals are crosstube ends. The replacements are tang mount on one end (crosstube replacement had ports in wrong place).

Since the replacement crosstube and tang are a little narrower that the original crosstubes, I figured I'd close the space with some 1" washers. From memory it will probably take maybe 2 washers on each side of the cylinder mounts, both ends of the cylinders.

I had wondered about bending the pins, but after reading the post yesterday I see it is a real possibility.

My question- How much spacing can be closed with washers (if any) on the cylinder ends? The pins are 1". I use a grapple on this 48HP tractor most of the time.

I thought about welding tube spacers on the cylinder ends but that scares me. I sure don't want to bend the original pins, they have grease fittings on the ends. My other thought is to maybe use a grade 8 1" bolt for the pins until the replacement cylinders come in.

Suggestions?

[mike_belben]

Use the washers with a big bolt insead of a pin to clamp the stack solid.  Then weld the washers together on the peripheral edge so they cant slide out of alighment with each other. This will help support the bolt shank from bending moment. 

[TroyC]

Thanks, good idea. I  was also considering tacking the solid washers to the ends of the cylinders. The crosstube end does not worry me on the welding, not so sure how much heat the tang end can take.

[fluidpowerpro]

Is the max cylinder travel limited by the cylinder itself or is it the structure of the machine that limits it. If it's the structure, then then pins are subjected to max load every time you hit the limits. If it's the cylinder itself, the cylinder body takes the full force, not the pin. Either way, you could also experiment with lowering the max system pressure by turning your relief valve setting down. It may still provide enough force to do what you need until your new cylinders arrive at which time you can turn the pressure back up.

[TroyC]

Max travel is limited by the cylinders. I'll look for the pressure setting.
Thanks!

[kantuckid]

I saw the word bucket by the OP. Improper back dragging seems to be the more common way people bend cyl's. Not pointing fingers, just a point.  

[TroyC]

I think you nailed it, 100%! My neighbor pushed some pines over for me. One of the larger ones did not get pushed far enough to pull all the roots out of the ground. After I cut the root ball off, I dug and pulled it out with the grapple. I'm sure dragging the grapple backwards is what did it. I had no idea that would happen (at the time).

You know the saying- 'you learn something new every day'. In my case, that education can get expensive. 

[mike_belben]

Oh yeah.
 
School of hard knocks can send a tuition bill any day of the week. 

[firefighter ontheside]

I bought a quick attach adapter for my tractor several years ago.  Kubota did not make one specifically for my tractor, but another one of theirs fits just fine.  I had to add about three 1" washers to each side of the adapter to make it secure.  This has not caused a problem.  I think it really just depends on how many washers you're adding, how big the pin is in the first place and what kind of stress you're putting on it.  I've lifted logs that are the max weight for my loader with no problem.  In fact, I broke both of my curl cylinders pushing arouind a log that was too heavy to lift.  The pins were just fine.

[TroyC]

I was hoping the cylinders would come from the dealer before now.

The cylinders I ordered will probably take two washers on each side to space out. They are on 1" pins. Since I learned not to backdrag with the grapple, maybe I won't ruin the pins or new cylinders. I looked at grade 8 bolts, really pricey. Think I might look into 1" solid pins at TS instead of gambling on the original pins not to bend.

Most of my grapple work is lifting trees for the mill so the pins will probably be fine for that. I sort of got carried away digging out the stump.

[Jediwood]

I bent pins on my thumb all the time. They were 1" so I drilled the mounting holes  out to 1 1/4" and bought good pins and never bent another problem. Food for thought