Thumb Home made thumb for mini excavator

[voodoo]

This set shows the brackets with the adjustable toplink in position. you can see it is a nice snug fit.
The brackets will be welded directly onto the digger and remain a permanent fixture. Everything else can be removed, or left in position as the need demands.

The fixing pins are standard 3/4 Cat 1 toplink pins.

 

[voodoo]

Now the thumb arm itself.

The first two pics show the unit "assembled" for effect. Nothing is welded yet.
I varied from the design drawings a bit at the front on the jaws in two respects.

The first was to cut a "vee" notch in the channel, grind a cut across and then bend the "v" down into the jaw. (pic #4). This I will then weld in place and should make the jaw more rigid and less prone to bending. The top cut will be fill welded to tidy up.

Secondly, I found a length of tool steel bar in the parts bin. Not sure what I had it for, but it is as hard as nails. I've cut this to the jaw pattern (pic #3)and will fillet weld to the main jaw arms. This will mimimise wear and also double the sectional thickness on the top edge. It also keeps the jaws slightly proud of the main thumb web plate.

 

[voodoo]

Here's the blunt 4" holesaw I was complaining about earlier.
I eventually got so mad with it when cutting the second hole that I took the chainsaw grinder to it and sharpened up the teeth. It improved things, but it remains the slowest part of the job so far.

Thats what I get for wanting to be fancy.

 

[voodoo]

Thats it to date.
Hopefully I'll make more progress tomorrow after the chores get done.

Nigel

 

[voodoo]

Well,
It's done and all installed.
Painted up on Monday past and now ready for work.
Some pics before going out to test

 

[voodoo]

View of all closed up and stowed out of way.

 

[voodoo]

Loaded up and ready for trial run.
I'll let you all know how I get on.

 

[3RRL]

voodoo,
Thanks for photos. That thumb came out really nice. The stow away position is excellent. I did find on mine (which is moving and mechanical) that I don't need to stow it for almost any digging I've done. It's really handy because when you need the thumb for a boulder or log, it's already there. You might want to try digging with it if it doesn't get in the way. Since yours is rigid, it might, but it's worth a try.
Great job on the project.

 

[MJPetersen]

Great Job. Very neat and tidy install.

Mike in Warsaw

 

[decinho]

Hi. one can find the complete design of a homemade mini excavator? Not found in Brazil... Tks