Homemade Articulated Mechanical Thumb

dtd24 · Feb 28, 2007

3RRL,
Real nice, you are like the grapple master!!!! I'm just going to follow your lead with projects. I don't know that I can keep up though. Still workin on my grapple for FEL.

My moto: One step by one step

3RRL · Feb 28, 2007

Thanks Scotty and dtd24,
I know everybody was waiting like you guys. I'm just glad it turned out so cool. After testing it out, I have the linkage set just about right for most grabbing and digging work. However, there are the different hole locations available in case I want to vary the amount the thumb opens and have it close faster or slower, depending how much I need to curl the bucket. But this setting seems pretty universal for now.

dtd24,
I saw your progress and you should be just about ready to build in steel after you eliminate that small interference problem. Maybe make the hinge mounts slight higher or cut out some clearance in the arms. You are doing a good job on it and I'll be watching your thread too.

HomeBrew2 · Mar 1, 2007

Anxious to see what payload that rig can lift and transport. The attached pic shows my limit and education as to front weighting ... with a baby tractor ... had to drop it and go get a full bucket of ballast to take the pebble to it's new home. I'm still amazed what a bit of geometry and phisics can produce with junk materials and virtually no fab time

tommu56 · Mar 2, 2007

Rob why not put video's on YOU TUBE?

tommmu56

3RRL · Mar 2, 2007

tommu56 said:
Rob why not put video's on YOU TUBE?

tommmu56

tommmu,
I didn't think of it. I have them on Photobucket now. Is YOU TUBE a public viewing domain? It's obvious I don't get out much.

STEVE, my bro...
Whoa, that is one big sucker in your hoe. I'll have to test my thumb on some bigger rocks too, but mine isn't fixed like yours, so it may not be as strong? But that water laden log had to around 1000lbs I would guess. Then again I have the dual bucket grapples for REALLY big boulders. I just have to exercise a little discretion.

tommu56 · Mar 2, 2007

Rob

YouTube - Broadcast Yourself.

I've never up loaded but some sent me a link one time

tom

dynasim · Mar 2, 2007

This was a great illustration of how things can be done! Thanks for the education.

One question, and it is a general one, also: Do you have to heat treat the welded areas after completion? I was thinking of welding some attachments to my trailer, and am worried about having a weak point at the welded area.

Chris

HomeBrew2 · Mar 2, 2007

Yeh, we all just do what we can do. For the big rocks, I just plow them with the buchet to where I want them ... too much shop time to do the grapple thing.
Hey, we had a bit of snow this week, had some losses from my old-growth cottonwood. Nice to have the thumb so I didn't have to "mud it out" ... see attached. I pinched it in the wrong place and it tried to yank my machine over ... I've pinched the wrong parts before and knew just what to do ... drop it and run before she can grab her gun

Timber · Mar 3, 2007

I so love your projects Rob. I was waiting for this one to be compleated. I don't have a hoe or any intention of getting one so I had nothing to realy add but it was fun to watch you work just the same. As I watch you guys play with the thumb I realize that as adults we never seem to loose the child inside. I see 2 boys and a little girl in a sandbox with a big TONKA truck LOL. You are truly an amizing individual. The vidios are great, I did miss the sound on the last few, is nice to hear the tractor while your working. Looking forward to the next one

3RRL · Mar 3, 2007

dynasim said:
This was a great illustration of how things can be done! Thanks for the education.

One question, and it is a general one, also: Do you have to heat treat the welded areas after completion? I was thinking of welding some attachments to my trailer, and am worried about having a weak point at the welded area.

Chris

Thanks again guys,
I'm glad some of you found the thread entertaining.

dynasim,
No, you don't have to heat the welded areas after completion. Letting them cool on their own is generally a good practice. Just don't pour water on them to make them cool faster. Doing that would cause stress and brittleness in the welded area.

Timber,
My Nikon camera doesn't have a microphone, but my wife's Cannon does. So hers are the only ones that have sound. Yes, I love hearing the tractor engine on those.