My father-in-law has a 2000 Deere 230lc with a manual thumb and he keeps ripping the welds off at the bottom of plate where the thumb welds to the stick. He wants to reduce the pressure to the bucket circuit, but idk if that is possible without losing digging power. Attached is a picture of the last time he welded it back on. any suggestions or feedback would be greatly appreciated.
Welds look like they are not the best. Was that done with some quality stick rod or some wire feeder. Not here to criticize, but pentration dont look the best. Simon C
Stick weld - he said he used 7018, single pass, because some local people told him it needed to be the weak point to not destroy the stick
I really really hate to say this, but to be brutally honest, hire a welder.
Everytime a person welds over the same spot the steel gets weaker. It is always better to put a good base plate out of some quality steel and attach to it so as not to weaken the main boom itself. Then if the weld cracks the main boom is not affected by it. That's how I see it. Simon C
Beat me to it. Way too fast, nowhere near enough heat, doesn't look like it was beveled at all. The bead for this weld should have been at least 3 passes (root pass, and 2 overlapping passes), and covered 2/3 of that edge.
With all due respect, the weak point should be in your hand. Operating the machine within its limits and capabilities should be the primary safe guard. Of course a safety factor should exist. Building a product to withstand expected nominal forces and complement the component it's attached to. And lastly breakout force. Any failure points by design to protect components from failure should be just that, designed. Insufficient, incomplete, sporadic ect. welding is not going to provide a consistent or predictable fracture point. Thickness, orientation and placement of members is much more reliable. More damage to the attachment and/ or machine may result from anything but. To the best of my knowledge any reputable thumb manufacturer out there today does not design their thumbs with a failure point or recommend during installation one be created through welding or any other means.
2nd the suggestion of hiring a welder. Those welds suck but what is he lifting or doing with the thumb that causes it to break. Is he picking rocks up and trying to make gravel?
You're absolutely correct. When I worked for ATCO Equipment/Blue Diamond Attachments, BD just flat out quit offering and selling manual thumbs, even the extreme duty super heavy duty ones. Customers kept breaking, bending, destroying them because of obvious improper use, but they'd send them in for warranty repair. Eventually BD decided "to heck with it, no more manual thumbs".
Another thing to note, you mentioned it was welded with 7018. Were they dry? 7018 is a low hydrogen rod, once the packaging can is opened they have to be used in hours, not days. After so many hours exposed to air they have to go in a rod oven. 7018 left in the air will absorb moisture, H2O, that adds hydrogen to the rod with defeats their purpose, result, contaminated weld. Myself, stick takes too long. I prefer MIG .045 flux core dual shield. The prep is as important as the weld. All paint in area adjacent to weld must be removed, clean bare steel. The thumb plates should be beveled on a 45 degree angle at least half the thickness of the plate. First root pass, second filler pass, and third cover pass. I've never had one break off.
I have heard that about 7018 and while I have had some issues, I will never believe my welds are junk because of using old rod. I do take precautions but in my experience, old rod may not run as well as brandy new rod but it still works fine, I do preheat the base metals and will lay the rod on welded areas to preheat if possible. I believe there are 2 camps here and if I’m welding something that is susceptible to breaking, I will take every precaution I can but in the end, it will still get welded. I have run 7018 in the pouring rain and have had rods get wet. Just dry them out in a toaster oven or rod oven. I have welded stuff with rods that were left in an unheated garage for 20 years and they weld fine. Not saying to not take precautions but a lot has to do with the guy holding the stinger.
^^^I have the same experience^^^ Up here, a popular rod is Arctec 223 (higher elasticity/tensile strength?). But basically a 'fancy' 7018 (I believe), expensive but I like them. They seem to laydown really smooth on our Bobcat 225, not sure why but the arc just seems smoother than standard 7018.... I keep them behind the wood stove! Likely not proper, but have never had any issues. When welding I set them on the hot exhaust grill of the welder.
See people keep welding rods in an old refrigerator with it wired to keep a high watt bulb on to keep it warm and dry
Or...try using a helmet next time.....
I keep hearing about this Arctec but can never seem to find any, would like to try some out sometime.
Seems a good product for sure. A good test was the completely broken rearmost frame cross-member on the Ford cabover in my signature photo. It has withstood extreme off-road twisting forces for the last 6 years or so in mountainous terrain. Veed out nice, grind clean weld with good amount of heat....
Arctec info...
Looks like some of the "super missile weld" rods. ^^^ https://www.harrisproductsgroup.com/en/Products/hpg-na-supermissileweldsmaw To hit the higher elongation shown on your box (32% get's you close to your 34%) You need "Ultra super missile weld"..... https://www.harrisproductsgroup.com/en/Products/ulsmw60 Filled with expensive alloys, when you chip the slag, you get a rainbow looking shiny weld. There's eutectic as well. EutecTrode® 966 Manual electrode for general fabrication and maintenance of structural work. www.castolin.com
Don't turn down the bucket circuit, turn down the pressure on the thumb circuit. I won't beat a dead horse about the welds.
I think it's a stationery thumb. We had a 308 with a thumb like a rat trap. Used to get it close, them use the bucket to squeeze
Learn something new every day. Been around this stuff 30+ years and never knew that was a thing.
Used to see them on backhoes. Any i have seen have holes where you can adjust the position. Use what you have i guess. Think it would be a pain loading a truck if you were sitting low.
Never have seen a manual thumb in 30 years???
Never. Everything that I've ever turned a wrench on with a thumb it has been hydraulic. Everything I've seen up close since I was a kid I don't recall ever seeing a manual thumb. Maybe its a regional thing?
Totally my opinion here so don't take it personal. Used to see manual thumbs in the east some. I disliked them so much I preferred no thumb. They require a lot of moving the machine around because they have a very small sweet spot for pickup and dumping. As soon as you're out of that sweet spot it won't pick up or it'll drop the stuff on the side of the truck rather than in the box. And it seems they always get bent or broken and if you beef them up to the point they can withstand the bucket force, the dipper stick starts cracking from forces it's not engineered for. When you pin them up out of the way they rattle and bang and generally get in the way of digging. If you drop them it takes about half an hour to remove them and another half hour to install and they're either in the way or placed well out of the way and forgotten about till all equipment is moved off and it requires a special trip back to the job to get it. They work OK in the right situation IF the operator is careful and light handed. Getting on a machine with a hydraulic thumb for the first time was like receiving an extra hand. Suddenly I was using a thumb for everything.