A really rotten day!

BigAl · Apr 8, 2004

What a day ! Finally completed my new grapple design today and attached the new hyd. ram I had been waiting for . This thing is "Extreme" heavy duty , #T-1 3/4" steel plate, #4140 1 1/2" & 2" solid steel rods , the best of everything and all welding done by a certified welder /forums/images/graemlins/cool.gif. Children have been known to start crying and mothers have fainted just looking at this thing ! Ok ,maybe not that bad ,but close . It looks like something out of Star Wars . It took two days just to set up the Hyd linkage the way I wanted it . I was getting anxious because I'll be leaving next week for 8 months and wanted it all completed and working correctly for when I got back to use it .
Well ,I cleaned up the last weld and me and the welder went looking for something to grab hold of ,to try it out . We found a steel I beam and I grabbed ahold of it . The hyd ram is attached to a solid 2" round bar and I bent it like a Pretzle !!! /forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif /forums/images/graemlins/shocked.gif The hyd relief valve is working correctly ,but I could not believe how much force that ram had . I just assumed it would go to the max and hit the hyd relief valve . So now it is back to the drawing board this next winter I guess , to design a new hyd system to open and close the jaw that won't break . /forums/images/graemlins/confused.gifThe good news ,if there is any, is the grapple itself did not bend .
Big Al

GerardC · Apr 8, 2004

/forums/images/graemlins/shocked.gif That's a bumber. Hope you get it all figured out before you go /forums/images/graemlins/crazy.gif. I know you've been working real hard on this project. /forums/images/graemlins/wink.gif

ns_in_tex · Apr 8, 2004

I know you would like the grapple to bend the steel I beam first, but if you can't, might try a smaller hydraulic cylinder or plumb in an adjustable pressure bypass on the cylinder you have.

I had to put one on mine. WW Grainger 6X843, 31.25 in 2002.

BigAl · Apr 8, 2004

I am beginning to think you are right about a adjustable pressure bypass valve . I still like the design but can't be bending the hyd. arm all the time . I been out looking at this thing and talking to myself for the last hour . Wife thinks I might have gone "over the edge" . /forums/images/graemlins/crazy.gifI did not intend to try and bend or crush the I beam .I just wanted to see the tractors hyd Relief valve kick in, if need be . Thanks for the idea .
Big Al

JimR · Apr 8, 2004

You need to find a chart that will show the cylinder pressure based on diameter of the cylinder tube using your hydraulic pressure. Or something close that you can figure out easily enough. I built a wood splitter years ago on my Ford 8N that I use to own. I used the rear mounted pump from my backhoe to run it. The release valve on the splitter never kicked on using the forward stroke. I was using a 4" cylinder with a 2" ram. I could and did bend the I-Beam of my splitter and broke off my wedge on one occasion because I was not paying attention. I then fitted plates into the end of the beam to box it in. I could still bend the beam if I wanted too.

stephan · Apr 9, 2004

I just bought a valve for a log splitter I intend building and from the documentation I understand that when the ram reaches the end of its stroke the valve centers itself. I understand this to be adjustable. Perhaps replacing your current valve with one of this variety. Also there is a hydraulic gauge you can get that you could plumb in after the valve and before the cylinder that would allow you to decide how much pressure you'd be putting on the grappled item.

B2400 · Apr 9, 2004

You didn't say what size cylinder you were using, but the formula for finding square inches of a circle is A=Pi(3.14)xradius squared. For instance: 3" cylinder would be 1.5x1.5x3.14=7.065 square inches of surface area. Therefore if your system produces 2000psi, you would have 14,130 pounds of pressure driving that cylinder. /forums/images/graemlins/blush.gif

BigAl · Apr 9, 2004

Thank you ! I never knew how they figured that . I will be able to use that information to decide what to go with on the new ram. My old ram was a 2 1/2" bore @ 2500 pounds .
Big Al

BigAl · Apr 9, 2004

Ok ! Today is a little bit better . I replaced the 2" steel tube and decided to use the tooth bar attachment to see if I could screw that up and not use the grapple at all . The good news is it worked as designed ! I was pushing over and popping out oak brush ,roots and all . The biggest piece I could pop out was about 5" diameter . I cleared about a half and acre in 2 hours . I then headed for the nastiest pile of rocks I could find and it just popped them right out . Now if I can get the grapple Hyd. linkage set up correctly I think I got a winner . My nieghbor just got his DK45 so we were able to run them side by side to compare clearing and digging performace . It was amazing to actually see the difference of what would stop him and what I cut and ripped right through . I won't be posting pictures until I get that hyd. linkage fixed .
Big Al