BH77 - has anyone considered converting mechanical thumb to hydraulic?

[bandit67]

I agree that reliefs are an important feature to avoid damage. However, if I find a kit without the reliefs built in, then that just means I will take more care, and use the thumb to clamp items rather than using the bucket curl cylinder to clamp. It is my own backhoe used primarily on my property for personal use.

wdchyd, I'm sure you see mostly commercial damaged thumbs, and as you know, commercial guys are extremely hard on equipment. Time is money, and everything they do is SIGNIFICANTLY faster than the work the average private equipment owner does, especially since the hydraulic systems on commercial units allow much faster movements. Something the smaller, non-commercial units are not capable of.

So if the "kit" I find to install on my machine does not have a proper relief valve on the thumb kit, I'll just take more care to avoid damage. If I was capable of designing & building my own hyd thumb conversion, then I'd include a relief valve.

As to that issue, I will find out if the company that is considering offering us a hyd conversion kit for the BH77, also includes the proper relief setup.

 

[bandit67]

I just got an email from the company that I've been speaking with after asking about the relief setup. I got this reply:

We don't usually do a cross-over relief system on the smaller backhoes (usually just on the larger excavators and backhoes), but I can definately look into pulling one together for you with pricing if you would like. On the smaller backhoes we size the hydraulic cylinder so that the column load of the cylinder can handle the breakout force of the bucket to avoid buckling.

The delay has been that they haven't been able to get their hands on a BH77 to get actual measurements off of. A while back, I offered to assist with getting them the dimensions if they had difficulty getting ahold of a BH77 at their local dealer, so they will be sending some dimension sheets for me to fill out and take pictures of my BH77 so they can get to working on a thumb kit for it.

I'll update this thread as I hear how things are progressing.

 

[wdchyd]

Check out this one from a thumb



it was 2.500" dia......believe it or not the cyl barrel was not damaged, the gland was wrecked though

 

[CHDinCT]

Check out this one from a thumb

View attachment 310125

it was 2.500" dia......believe it or not the cyl barrel was not damaged, the gland was wrecked though

A little duct tape and it should be good as new.

 

[CanuckPT]

I just ordered a mechanical thumb for my Kubota BH77 from Richard at Bro-Tek! Can't wait to bolt that puppy on and try it out when it arrives!!

 

[bandit67]

Update on the hydraulic thumb option. The company I've been talking to is working on it right now. I've submitted photos & dimensions to them to get their current compact hydraulic thumb version modified as required to fit the BH77, because they had not been able to get ahold of one locally. They are hoping to get their hands on a backhoe in the next few weeks to set everything up and test it. If they can't get ahold of a BH77 in a reasonable amount of time, we've discussed doing final fitting/testing on mine.

We're discussing 2 options for thumb control.

Hydraulic Foot Pedal Control: Includes 2" Bore Hydraulic Cylinder, Hydraulic Control Valve with Foot Pedal, all hydraulic hoses and fittings for connections, and any pins and mounting hardware required.

Push Button Control on Backhoe Joystick Handle: This set-up would include a new control grip with a built in momentary switch, electric selector valve, 2" Bore Hydraulic Cylinder, and all hydraulic and electric connection hoses/fittings/etc. Selection would be between the boom swing function and thumb circuit. This would give you the thumb control in your left hand and bucket control in the right hand so you could use them at the same time. Also, the thumb control and bucket control would both be in the left-right direction of the joysticks.

 

[ericdube]

Update on the hydraulic thumb option. The company I've been talking to is working on it right now. I've submitted photos & dimensions to them to get their current compact hydraulic thumb version modified as required to fit the BH77, because they had not been able to get ahold of one locally. They are hoping to get their hands on a backhoe in the next few weeks to set everything up and test it. If they can't get ahold of a BH77 in a reasonable amount of time, we've discussed doing final fitting/testing on mine.

We're discussing 2 options for thumb control.

Hydraulic Foot Pedal Control: Includes 2" Bore Hydraulic Cylinder, Hydraulic Control Valve with Foot Pedal, all hydraulic hoses and fittings for connections, and any pins and mounting hardware required.

Push Button Control on Backhoe Joystick Handle: This set-up would include a new control grip with a built in momentary switch, electric selector valve, 2" Bore Hydraulic Cylinder, and all hydraulic and electric connection hoses/fittings/etc. Selection would be between the boom swing function and thumb circuit. This would give you the thumb control in your left hand and bucket control in the right hand so you could use them at the same time. Also, the thumb control and bucket control would both be in the left-right direction of the joysticks.

Personally, I think the hydraulic foot pedal control would be the way to go. This is identical how you operate the thumb on larger backhoes, and works quite well.

Do you have any estimates on the cost? I'm going to be buying a BH77 backhoe with my B3350, and depending on price I might consider upgrading to a hydraulic thumb depending if the price was reasonable. Thanks!

 

[bandit67]

Mini Ex's have the thumb control in the joystick controls. That's the only machine I've used a hydraulic thumb on. None of the full size TLBs I've run have had the thumb.

My concern was getting the foot control set up so that it doesn't take up too much platform space, because there isn't a lot of spare room, but we've had discussions on that, and thrown some ideas back and forth, as per an email response:
"I understand your concern with the foot pedal. I think if we were going to go that route we would probably mount the pedal on a small platform off to the side like you suggested earlier. From what I could tell from your pictures that should certainly be plausible. As for feathering, you can control the thumb pretty well with the foot pedal. We also size the lines, valve and cylinder based on the GPM and Pressure of the backhoe so that it functions smoothly, so I don't think you need to worry about that part."

Pricing I've been given is $595 for foot pedal & $990 for pushbutton control. Their current model foot pedal is $595. Not sure if adding a small platform for the foot pedal will impact price. "Price Includes 2" Bore Hydraulic Cylinder, Hydraulic Control Valve with Foot Pedal, all hydraulic hoses and fittings for connections, and any pins and mounting hardware required."

If the foot pedal option can be set up without eating up too much platform space, I'll probably go that route, since I also need/want to add a 3rd function valve to the FEL so that I can finally add hydraulic angle rams to my snow plow this year.

None of these hyd add-ons are cheap, but I'm tired of wasting time having to manually operate the thumb, snow plow angle, etc. Over the life of a machine, it's a small price to pay. And I'd get a lot more use out of the attachments if they were easier to use.

 

[jim_wilson]

Excellent.

Glad to see somebody is looking into this - I've been thinking of doing the exact same thing on the BH77 hoe on my B3200.

I hadn't seen anybody offering a kit to do this - so I was spending the time searching all over the internet to see if there was a cylinder available that would work - trying to figure out where to mount the valve - and plumb it in to the existing valve stack - etc.

The plumbing out to the cylinder is the easy part - the BT820 hoe on the B26 tractor is so similar to the BH77 in size - that I bet you could just lift the plumbing from the valve out to the cylinder from the BT820 and use it on the BH77.

How far along is this company in developing a solution Bandit67?

Any idea on what the cost will come in at?

I am definitely interested in this if something comes together.

Where is this company you're dealing with located? Any TBN'ers local to them that could let them take a look at a BH77?

 

[bandit67]

I expect that they should have it ready for us in the next couple months. They've been trying to get their hands on a BH77 locally. If they can't do that soon, then we'll use my machine to test everything. They already have a thumb kit for compact hoes with a hydraulic upgrade to their kit - I just asked them to retrofit the hydraulic upgrade to the BH77's mechanical thumb.

See pricing they've discussed in my post above.