I just recieved my new Bodine mechanical thumb and am going to weld it to my Hundai H-140 I will be using a stick machine with 7018 rod. Any tips or suggestions? I do know to disconnect the batteries and place the ground near to the weld area. Thanks for any help!
Apparently its not good to weld across the stick frame, just down the edges so it does not weaken it and break your bucket off.. I've tried a manual thumb and converted it to hydraulic pretty quick as it is much stronger, quicker and user friendly, but I wish you good luck and efficient work!
I posted some pics on this, a few years ago: One thing I might do differently, except that the thumb's directions called for a specific spacing from the bucket, would be to mount it a wee bit further up the dipper. Where it is now makes it really difficult to change buckets, not because there's any physical interference, but because the thumb does a really effective job of blocking your view of the end of the dipper as you try to line it up with the holes in the bucket. Lots of mounting and dismounting the machine, unless you have a helper to eye things up for you. Judge for yourself whether that's possible in your case. Something else you might want to think about, is something to cushion the thumb and it's pins from banging around when you're digging. I finally put an old piece of carpet in there, just so I wouldn't have to listen to it clanging back and forth all day. I just reviewed that old thread, and one thing that didn't get mentioned is that you only weld lengthwise on the thumb and dipper, no welding across the dipper. I believe that was also included in the instructions, but it makes sense, in that you don't want to heat the metal up across the dipper and make a weak spot there. Good luck, and let us know how it turns out. When you really need a thumb, even a manual thumb is a great addition to a machine. :thumbsup On edit: Apparently Logan posted while I was searching for that old thread and typing my reply. Obviously we agree on not welding across.
For mechanical thumb you had better consider adding a plate to the stick from the bucket pin all the way up to the stick to boom mount pin. The reason is that the bucket operates at system pressure while a hydraulic thumb is always reduced down to around 2,100 PSI which lessons the force applied on the stick. For years Komatsu required an additional plate even for the hydraulic thumbs. When I went to work for the Link-Belt people they also came out with a bulletin requiring the extra plate. You can weld across the stick down at the bucket pin but at the boom end you need to cut about a nine inch female chevron in the plate and whale tail all your welds. You need to have the female chevron on both sides of the thumb base plate also. This prevents the stick from beer canning when ever you clamp onto and pick up a heavy item. Good Luck!