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.
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.
