hi guys. i recently built a thumb for the old ck. thought i’d post a couple pics and see what others think of it. the tines are built from ar400 plate and the rest was built from regular mild steel bits. pins are just some pieces of shafting i had laying around. i laid a small bead of hardfacing weld on the top of each tooth and a few beads on the tips of each tine to help with wear and tear on the tines. seems to work well. unloaded around 45tons of armor stone recently for a retaining wall i built. it was invaluable for moving the big rocks around. i just purchased a replacement backhoe for the old ck and will need to cut off the thumb and mounts to weld them to the new backhoe and thought i’d post some pics in case anyone sees a way i can improve it when it’s cut off to be welded on the new (to me ) backhoe.
last pic is the finished product. added extra ar400 side plates to the tines to help strengthen them a bit. 1/2in with 1/4 in stiffeners for a total of 3/4 inch thickness on the tines.
Look like it gets the job done nice job
thanks. wish it could have been hyd not manual but it’s kinda tough to tap into the hyd system on this old relic. read some stuff guys have done to tap in but most seemed unsafe as they bypass or mess up the relief or something? i decided to just get off the seat and adjust as needed instead of damaging something tapping into the system.
Nice, looks handy.
Nice work, Looks like that will save you some time on a lot of projects. Trying to pick up odd shaped stumps and rocks really grinds my gears.
I really need to look into something like this, though I should have months ago. I've got some trees (logs) to move around and eventually rocks as well. It looks very handy. Your fabbing skills look great!
A thumb looks like a much more stable and controlled way to move around rocks. Have any of you tried using some rock tongs? My backhoe bucket has a hook on the backside and have thought about using a pair since i lack the skills to build a thumb like yours ^^
rock tongs?
Looks good and you’ve proven it works with the heavy rocks. It’s always satisfying to make something yourself. Job well done!
A couple of those rocks look pretty big and heavy, were you actually able to grip and lift them clear off the ground with your diy thumb? That’s fantastic, nicely done.
yeah they are very heavy. some of the truckload of stones were too heavy and the relief valve opened up. setting them down real quick lol. was able to get all 40 ton of armour stone off the trailer without damage to the machine or the trailer. i’m going to add another support out closer to the tips of the tines as they did bend a little bit. itching major tho.
How easy is it to get into trouble with using a thumb on a hoe? I am assuming when you use it, you are not lowering the stabilizers? Does that work out ok if you keep the boom centered and just move the machine around to position the object to drop it off? I supposed you have to watch out if you want to swing the boom around to the side with a decent load with the thumb and set the stabilizers down first?
A couple of questions about the teeth on your thumb and the geometry of the thumb: - The teeth look sharp and time consuming to cut, what did you use to make the cuts for the jaws and teeth? - Do the teeth help the most with gripping and holding things or is the “hook” of the thumb and the tines on the bucket which get under the load, more important for grabbing and lifting. - How about the placement of the pivot of the thumb along the stick, it seems that if it was placed further back along the stick from pivot of the bucket it would allow you to get around and under objects you’re lifting, or not ? Thanks !
It's not easy to get into trouble with a thumb. Common sense is the rule. Most of the time the stabilizers need to be down. If they aren't a lot of stress is put on the rear tires and the machine will be very unstable. Boom centered ? It depends on how heavy and far from the tractor the object you are picking up is whether you are sitting still or transporting anything. Swinging the boom with the thumb holding anything again depends on how heavy the object is and how far the boom is extended. I have moved a lot of trees and concrete slabs with the stabilizers up. It's hard to drive anywhere with them down.
“…with the stabilizers up. It's hard to drive anywhere with them down.” But gosh knows, I’ve tried plenty of times !!!
We all have when we get in a rush
i have not tried lifting anything more than some brush and sticks without the stabilizers on the ground. i did break a tension rod when unloading the rocks and luckily nothing more serious happened.
they are quite sharp. i cut them by hand with combination of plasma cutting and zip cut on a grinder. i don’t know the teeth benefit from being sharp. just thought they might grip logs and things better that way. seems after some use it’s more the tips of the tines that hold objects in place. or they get “pinched” between the tines and bucket sides. as for the placement… u may be right. i made it to have several pin locations for placement and adjusting it seems to get the tines in a location that will get ahold of anything i have tried to grip. definitely think there’s room for improvement tho. i really just placed it there because with the tines at 90* to the dipper, and the bucket at 90* to the dipper as well. it placed the tines and bucket parallel, as well as gave enough room to fold it away when. it needed. i have since removed and swapped out that backhoe attachment for a different one in better shape. i will be cutting the thumb and brackets free of the hoe in the pics and welding it to the new attachment. i will look at the location for the thumb mount closer before i weld it on and see….
One last question, it looks like there is just a single strut/brace on one side only that holds the thumb at 90*. Has that been enough, Id have thought the large bucket hydraulic cylinder would bend that single strut and more support would be necessary to counter the force of the bucket when really squeezing something.
pic of it folded up. will be cut off and this beat up old attachment will be stripped down and mostly scrapped out. will keep the cyls for spares or to repurpose somehow. maybe a big log splitter..? the main frame that attaches to the tractor seems like it could be used to make a diff attachment mount maybe..? the thumb will definitely be moved to the new backhoe tho. just wish it was easier to tap into the hydraulics and make it powered.
the strut bar is heavy wall seamless pipe, and it is centered between the tines. it attaches to a pair of 3/8 thick brackets welded to a piece of 1in thick x 4in wide flat bar. and is also gusseted for good luck lol. i was concerned it would bend also but it seems to hold strong so far. when moving the rocks i had to hold pressure on the bucket curl continuously in order not to drop the heavier rocks, and the strut stayed straight. see what happens over some time. the piece of channel closer to the pivot was just for added rigidity by the pivot. (was all just scraps and left over stuff from other jobs so i used what i had and figured i’d strengthen and modify as required).
I’m going to order one of those manual thumbs from Titan and reinforce the holes with DOM tube as suggested. I can’t decide whether to order the 32” or 36” thumb. With the bucket positioned 90 degrees to the dipper, it measures 33.5” from bucket tooth tip to dipper. I’m sort of between the 32 & 36” lengths , all other aspects seem about the same except: a) maybe the 36” model stows better b) maybe the 36” model is more rigid because the strut is longer... It’s hard to know without owning one. Any advice ? 32” mode l - https://www.palletforks.com/tractor...mb-58-inch-steel-plate-attachment/122994.html 36” model https://www.palletforks.com/tractor...plate-assembly-weld-on-adjustable/122982.html
I would buy the 36" Extreme duty. If the small amount of overhang is a problem it would be quite simple to trim it with a cutting torch or a saw. You will find out quickly after using it a couple of times if it is tooo long.
Okay, thanks !
Nicely done!
I really like the idea of adding a thumb to the back bucket for firewood, my question is tho, how much harder would it be to add a hydraulic thumb? You would need to plumb In a diverter operated off of maybe the outrigger. I've been thinking about this for the last month and a half . That and adding a grapple on the front bucket.
i would have preferred to build it as a hyd thumb but it’s difficult to safely tap into the hydraulics on this old machine. i thought about running it off the bucket cyl but don’t like the idea of not having dedicated control for it and having it move with the bucket. i read some stuff that if u tap in to the system wrong , u can render the relief useless and potentially create a dangerous situation where there is no relief valve possibly leading to damage or even injury. not being terribly knowledgeable with hydraulics i opted to just make it manual. figured i could likely convert it if i ever find a safe way to make it work hydraulically. without spending a fortune also. lol
I had good results plumbing a 6 way diverter valve and using a stabilizer valve for my thumb. I posted a thread with all details a while ago.
i will have a look for that thanks. once i get the valve leak issue fixed up i’m going to be putting the thumb on the “new” backhoe attachment. it’s currently still welded to the original attachment.
I wanted to look at it also, here it is HeavyEquipmentForums
Nice to see how another welder goes about building something. Tried and true methods used and not something that makes people cringe looking at how it was done. For people without the required skills, they might be pleasantly surprised at the cost to have someone experienced help them with the welding and/or designing. Thumb up.