homemade manual thumb

[Funny farm]

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.

 

[Funny farm]

 

[Funny farm]

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.

 

[Jonas302]

Look like it gets the job done nice job

 

[Funny farm]

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.

 

[Ben House]

Nice, looks handy.

 

[Nhshaun]

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.

 

[aighead]

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!

 

[Nhshaun]

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 ^^

 

[aighead]

rock tongs?

 

[Scout_1969]

Looks good and you’ve proven it works with the heavy rocks. It’s always satisfying to make something yourself. Job well done!

 

[Birdseye]

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.

 

[Funny farm]

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.

 

[franklin2]

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?

 

[Birdseye]

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 !

 

[Tinkerer]

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?

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.

 

[Birdseye]

“…with the stabilizers up. It's hard to drive anywhere with them down.”

But gosh knows, I’ve tried plenty of times !!!

 

[Swetz]

But gosh knows, I’ve tried plenty of times !!!

We all have when we get in a rush

 

[Funny farm]

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?

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.

 

[Funny farm]

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 !

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….