View Full Version : Articulating thumb for Massey Ferguson gc2410 sub compact bac

04-16-2011, 08:37 PM
This is an articulating thumb that I made for my fatherís sub compact Massey Ferguson gc2410 backhoe. It is based on the articulating thumb made by Amulet. The challenge was fitting all the mechanism in such a tight space, getting all the holes to line up, and making sure it was not overly constrained.. There were a few times that I did not think that it was going to happen. I chose to start with cardboard pattern, then jump to plywood patterns to experiment with link positions. I did not want to do it all on CAD since that is my day job.

The main jaws, cut out on my bandsaw to avoid having to clean up flame or plasma cut mess.



Light clean-up on the belt sander.

Stack drilling the holes.

04-16-2011, 08:38 PM
Since I was tinkering as I went I chose to use light presses on the steel bushings that I made, so I could reposition them before welding. Inside each steel bushing is a bronze bushing. Lots of turning.

Making a steel bushing for a pressed in bronze bushing. Ouside turning, inside boring, pressing in not shown, reaming ID, then part to length.





04-16-2011, 08:38 PM
Pressing a bushing into one of the arms.


One of the back links



Figuring out the kidney links. Needed to trim the ribs on the buckets a little here.


04-16-2011, 08:39 PM
Starting to figure out what to do in this little space. Every offset is critical since I want the bushing bosses to stick out a little to keep the flat sides of the links from rubbing, and there is also some bucket slop to deal with.





04-16-2011, 08:40 PM
Making some of the new shafting from TGP. Due to space I needed to switch to retaining rings. I also bought some hardened washers and turned them a hair over the shaft size to run against the retaining rings. Also opened up some bronze thrust washers.

Retaining ring groove.



One shaft I welded a cap on with, using my weld spin fixture I made a while ago.


04-16-2011, 08:41 PM
Pieces all painted up


Tight space



I set it up so you can slide the kidney links out and clamp the arm up out of the way when you don’t want to use the thumb. The 2 positions for the kidney link mounting alter the attitude of the thumb, and whether the bucket is curled out more or less when the thumb closes.


04-16-2011, 08:41 PM
I’ll post a video someday, but in these 2 shots you can see how the bucket and thumb open and close together. All in all I have about 35 hours into this – including head scratching time. Certainly one of the more challenging things that I have made without plans.
UPDATE: Delivered it to my Dad on Easter and installed. Thank goodness it works great. Two video links here (big files). Video skips a little on first load - play twice to avoid clipping and skipping. (click on picture for video)

Close and open empty:

http://i222.photobucket.com/albums/dd48/tool_collector/massey%20ferguson%20thumb/th_emptythumb.jpg (http://s222.photobucket.com/albums/dd48/tool_collector/massey%20ferguson%20thumb/?action=view&current=emptythumb.mp4)

Moving a small rock (sorry for the shake, one hand on camera phone and operating with the other):

http://i222.photobucket.com/albums/dd48/tool_collector/massey%20ferguson%20thumb/th_thumbrockmove.jpg (http://s222.photobucket.com/albums/dd48/tool_collector/massey%20ferguson%20thumb/?action=view&current=thumbrockmove.mp4)



04-16-2011, 08:46 PM
Damn! That is nice work! My last BH had a thumb, but it was stationary and the bucket closed against it. Once you have a thumb on your bucket you will wonder how you lived without it.

Liger Zero
04-16-2011, 09:17 PM
That almost looks as good as a commercial unit with that extra-shiny paint. Very nice job.

04-16-2011, 09:25 PM
Nice job. I see you welded the two arms together with a horizontal link. Did you have to line bore the bronze bushings when you were done welding to prevent binding on the pin?

doctor demo
04-16-2011, 09:47 PM
Damn! That is nice work! My last BH had a thumb, but it was stationary and the bucket closed against it. Once you have a thumb on your bucket you will wonder how you lived without it.

A stationary thumb doesn't work well for a lot applications, ya have to be lined up just right to get any production out of it.

It only took about 6 years of kicking and screaming to get a former employer to let me put a hyd. thumb on a backhoe, then after the V.P. watched how great it worked out on a couple of jobs He wanted to know why I didn't insist on one sooner.....I wanted to beat him.

I'm not sure how versatile that is compared to having a separate cylinder on the thumb, but it must be way better than a fixed thumb would be.

Going from thumb to no thumb is almost as painful as having your own thumb removed:eek:


04-16-2011, 09:57 PM
gda -

My boss bought an Amulet thumb for his Cat 416C backhoe about 6 years ago and never installed it. The backhoe is gone, but the thumb remains underfoot. I've had ample time to study the details of it's construction. It's pretty nice, but yours looks like an improvement.

04-16-2011, 10:12 PM
nice job - on the project and the photos

04-17-2011, 09:00 AM
Sweet,very nice job.

04-17-2011, 09:07 AM
Very nice job on the entire fabrication. Looks first class!

big job
04-17-2011, 09:14 AM
I been drooling about that piece of steel. Most Ive used were fixed, on
big Cats but hydraulics rules. Very nicely done.

04-18-2011, 08:24 AM
Thanks guys.

The big plate of steel was only $10, it was Blanchard ground to 0.580" for some purpose and never used and was on its way to scrap land since it had no other use and was an oddball thickness.

I did not have to line bore when finished. While making I tried to keep everything square, and made one steel bushing about 0.010" undersize to take up any tolerance errors. I welded the cross brace in place with the arms on the pin to help alignment and everything clamped hard with. It ended up pretty good. I just kisses one of the bronze bushing open a hair with a flap wheel on a die grinder to make it slide a litter easier.

Black Forest
04-18-2011, 10:27 AM
Does the thumb open and close everytime you curl your bucket? If it does that would not make me happy.

I have a thumb on my excavator but it is separtely controlled with its own hydraulic circuit.

The thumb is absolutely a great add-on for any excavator.

04-25-2011, 04:59 PM
UPDATE: video links added of installed ond operating thumb in post #7 !

04-25-2011, 07:55 PM
I just made one for my Nissan 3 ton, was going well till i picked up a lenth of old concrete foundation off a wall, it bent like a coathanger, back to the drawing board and 1" plate instead if 1/2" i guess