This summer I added a thumb to my Case 580B. Here's how it went down. This is the thumb I bought: https://www.amazon.com/gp/product/B01EIS1QES/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 And the welding wire I used: https://weldingsupply.com/cgi-bin/einstein.pl I went with a slightly longer thumb than the bucket (read the item description in the link). The long thumb causes a little issue when working with it at 90 degrees because when the arm is extended out half way or farther it hits the ground and the bucket does not, this only matters if picking up things smaller than a few inches which was rarely an issue. With the thumb pin moved to change the angle it works well, kind of like pinching something between your thumb and index finger, and is good for demolition work. I also figure I could cut off the end if it was a problem. Here is where the arm need to be welded. As you can see there is an upside down Y factory weld pattern. The back plate for the thumb is flat, so that's a problem. My solution to the non-flat surface was to add a 3/4" steel plate to make the surface flat for the thumb. Before adding the plate I used a grinder and cut out a Y pattern in the plate. Now the plate can sit flat yet is thick enough to not lose any strength. Welded each side. Assembled the thumb and test fit. Most people advise to just put this as low as possible and that seems to be true although it's not all the way down on the arm. Welded on the thumb back plate. This turned out to be a trouble spot as the C shape allowed the 2 edges to open up wider while welding. I'd recommend using some long 1/2" bolts through the holes to keep the edges from opening up. Welded all sides. The results? It works fantastic, although the outer pin has bent slightly. I had an old barn/house to remove and this made it much easier. At times it was clumsy and had to move the backhoe around a little more than I hoped, but it did the job. An extend-a-hoe probably would make life a little easier. Or a hydraulic thumb.
They are handy. I put the 36" on mine last year. HeavyEquipmentForums
I read through dozens of threads before I did mine, your thread was one of them. Looks like I used a bit more wire on mine
Nice job I used a titan my self they look a lot stronger. I used a stick welder for mine
I'm sure that thumb will come in very handy for you I could have used one many times.
Thanks guys. I already demoed a house with it, making it one of the best return on investment ever. Was able to sort materials and fill a roll-off dumpster with ease. From house to cleaned and flat land in about a month in my spare time.
How does that one lock back out of the way when not in use?
I'm not sure. I just take it completely off when I'm going to dig a lot. I believe the stiff pins comes out of the thumb, then one gets put back in using one of those three holes on the back plate. I was going to attempt it, but since I have to take 2 pins out I figured why just fold it back, might as well take it off.
I want to install a hydraulic thumb on my 580k 1st gen 1987 and I was advised by the thumb maker to install a pressure relief valve. I will be entering the hydraulic line at one of the back lever. I understand the the case has to pressures one main at about 30lb and one at about 10 pound pressure. Do you have any idea which of the two pressures is at the lever?