Thumb addition causing dipper stick damage?

UWAdventurer · Mar 17, 2012

Has anyone had issues with dipper stick damage after adding a thumb to their back hoe? I am looking at a mechanical thumb with the possibility of hydraulic conversion later. I wouldn't think it would be a problem because Woods offers a thumb option, but my dealer says their may not be enough strength in the arm.

Adiredneck · Mar 17, 2012

No problems with mine.

dfkrug · Mar 17, 2012

UWAdventurer said:
I wouldn't think it would be a problem because Woods offers a thumb option, but my dealer says their may not be enough strength in the arm.

Woods offers thumbs for the Groundbreaker X series, but not the older
7500, AFAIK.

The 7500 dipper stick has very thin walls and it is not designed for
forces directly acting on it. The 2 end pivots use welded-in DOM tubing
to add strength at these points. If you decide to weld a custom
thumb on the dipper (or one you buy off the shelf), you must strengthen
the dipper at any connection point. For my thumbs, I weld on reinforcement
plates and have no problems (fixed or hydraulic).

There is a bolt-on thumb out there that has been known to slip under force,
and even distort the dipper.

UWAdventurer · Mar 17, 2012

According to the manual my back hoe is a BH7500. It does not mention "Groundbreaker" so I am assuming it will need reinforcement.

dfkrug: Could you be more specific how large and where you placed the reinforcement? I don't have any experience with this type of application, so I am looking for any help and expertise I can get.

I was looking at a bolt on mechanical thumb from Hound dog BT75-SH.

Thanks all.

dfkrug · Mar 17, 2012

Here is a thread where I deal with the structural issues:

http://www.tractorbynet.com/forums/build-yourself/125912-custom-hydraulic-backhoe-thumb.html

I am not a fan of the bolt-on thumbs. The forces are large, and the
the attachment should be securely welded, IMO.

That said, you CAN install a thumb on the old 7500, if you do it right.
You will wonder why you waited....

UWAdventurer · Mar 18, 2012

I checked my back hoe this morning and it is a Woods Groundbreaker BH7500, with that being said is additional reinforcement necessary for the addition of a bolt on mechanical thumb? I am assuming the Groundbreakers are built stronger? I am going to go with a bolt on because I have some limited use for the thumb and I don't think I can justify the cost for the weld on and hydraulics.

Nice write up dfkrug.

Thanks all.

dfkrug · Mar 18, 2012

UWAdventurer said:
I am assuming the Groundbreakers are built stronger?

Stronger than what?

After the "Du-Al", Woods made the 750, then the 7500, then the BH80-X.
All were about the same size (7.5 dig depth) and weight.

Looking closely at the curvy-boom series, I can not see if the BH80-X
uses thicker dippers than previous units, but, based on the fact that they
don't really weigh significantly more, I doubt it. Most hoe attachments
of this class are going to have thin dipper walls, since weight is a concern
and it does not need to be very thick as long as you don't push on
them in the wrong places.

As for my thumb projects, thanks. Hydraulic is WAY more work and cost
vs. a simple mechanical thumb. It says something that Woods welds
an upper attachment to their BH80-X dippers, whether you opt for that
very expensive option or not.

nickel plate · Mar 18, 2012

UWAdventurer said:
I checked my back hoe this morning and it is a Woods Groundbreaker BH7500, with that being said is additional reinforcement necessary for the addition of a bolt on mechanical thumb? I am assuming the Groundbreakers are built stronger? I am going to go with a bolt on because I have some limited use for the thumb and I don't think I can justify the cost for the weld on and hydraulics.

Nice write up dfkrug.

Thanks all.

Woods only builds thumbs for the later version of the Groundbreaker, the Groundbreaker "X" series, BH90-X and more recently the BH80-X series. Although your BH7500 is a fine backhoe, it is not in that grouping that offers a mechanical or hydraulic thumb built by Woods.