Kubotabilly, great progress! Looks great!
I hope you don't mind if I interrupt you with some questions. Your project has been a great model for some of my design ideas.
It looks to me like your rear cyl support is quite high. If you clamp that log are you worried about bending your mount? Of course you may not be done beefing that area up. I could not find your tractor's hydraulic relief valve pressure, so I used 2350 psi. This will give you about 7,500 lbs of force on this moment. This looks like it could be an 18" or greater moment.
If you are interested, I computed some placement values. Because I don't have your dimensions I guessed. So if you are interested in considering them, you can first check and see how close I got.
Assumptions:
Cylinder, 2 bore, 8 stroke, 26.25" retracted, 34.25 extended
I can't tell how long your grapple arms are, but if the length (in the picture below) from C - D can be 30.25" (and my cyl dimensions are correct, my placement values should also work. My numbers will open the grapple full vertical and substainally shorten the grapple rotation moments making it less likely to bend under load.
My placement numbers (pin centers):
B - C = 3.75"
A - B = 4.25"
C - D = 30.25"
Please understand that I am not a professional /forums/images/graemlins/smile.gif so don't over commit on these values. They look pretty good to me.
You have your cyl rod mount slanted back. For these values to work on a cylinder that long, that mount would have to be move out probably close to the bend to get the C-D distance of 30.25".
If my dimensions were wrong, but close, and you want new ones, let me know. I would be glad to help if I can.
Other values that may or may not be interesting.
Cylinder push force (based on 2350 psi) = 7,383 lbs
Cylinder pull force = 5,047 lbs
Cyl extension speed (open to close) = .4 seconds (full throttle and valve)
Cyl retract speed (Close to open) = .3 seconds
I think that definitely calls for a restrictor.
I can't tell you the speed yet with a 1/32" hole at 2350 psi.
The cylinder will consume .43 quarts of hydraulic fluid closed (max, does not consider hose volume).
I hope this doesn't cause another night of tossing and turning.. /forums/images/graemlins/grin.gif
