B21 custom hydraulic thumb, using B26 factory option parts?

[joea99]

Have a B21. Never had a thumb option I know of so I purchased a mechanical bolt on thumb from Bro-Tek couple years ago. Works well enough, but, it is a manual thumb and so I have to curl the bucket to it. As the design is such the thumb cannot move any more forward and still stow properly, I often find I have to curl the bucket too far for convenient grabbing of the target. That's just how it is.

So, contemplating rigging it up as a hydraulic thumb which almost forces me to relocate the pivot of the thumb to where most hydraulics seem to be. Sharing the bucket pivot point. Unless I mistake the pictures I have seen. Main obstacle is modifying the thumb to have "ears" or something to fit around the bucket and finding/making longer pins to go through and allow proper greasing. making the mount points and lugs for the cylinder eyes seems just a bit of fun and frustration. But the pins present a bigger problem for me, not having a real machine shop or even a suitable metal lathe.

In a flash of (possible) brilliant insight I recall the B26 is very similar even using all the same 3pt hitch stuff. The B26 does have a "factory" hydraulic thump option. That got me to thinking I could just buy the pins, grease fittings and bushings from Kubota and go from there.

While I suspect the lengths and diameters of the pins would work on my existing buckets, I'd like to be more confident before plunking down even small change (as these things go). A hundred or so is still a hundred or so, especially if it is thrown down a hole.

Anyone know for sure? I can post part number, if needed, but, won't unless asked.

Thanks in advance.

 

[Smokeydog]

Looking at parts diagrams from Messicks would give you insight into design and part differences. Was a thumb an option for the B21? That would be your best choice. Kubota and other manufacturers are not good about sharing between models.

Never operated a manual thumb. Only problem with a hydraulic thumb is once you use one is hard to do without.

B26 backhoe quick attach is the best system I have ever used.

 

[joea99]

Looking at parts diagrams from Messicks would give you insight into design and part differences. Was a thumb an option for the B21? That would be your best choice. Kubota and other manufacturers are not good about sharing between models.

Never operated a manual thumb. Only problem with a hydraulic thumb is once you use one is hard to do without.

B26 backhoe quick attach is the best system I have ever used.

Never an option for B21 that I know of. I did look over the B26 parts list but there are no measurements, that I could decipher. Like I said, I could order the pins to find out, but seems wasteful at this point, when someone might actually know.

Is the bucket a quick attach also? The B21 is not.

 

[Smokeydog]

Quick attach buckets is an option. Works well with the hydraulic thumb. My B26 came that way with three buckets so didn’t have to figure anything out.

Quick search found a couple after market thumbs for the B21. Considerations on weld on or bolt on for stick strength.

 

[joea99]

Quick attach buckets is an option. Works well with the hydraulic thumb. My B26 came that way with three buckets so didn’t have to figure anything out.

Quick search found a couple after market thumbs for the B21. Considerations on weld on or bolt on for stick strength.

Tend to think a weld on lug for the cylinder pivot would be best. The stick has more steel further up and I can weld in a plate or two if needed.

 

[joea99]

I found a post/thread on this subject that may pretty much cover all the issues.

B21 Backhoe Thumb

After 10 years I finally decided to install a hydraulic thumb on the B21. I was getting ready to make the thumb, and looked at Kubota parts diagrams to get some ideas. I learned that the BT751 backhoe and the BH77 backhoe use the same bucket pin. Meaning the buckets and also the mechanical...

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