Excavator and backhoe thumbs?

[Geoffm]

Who has a thumb on their excavator or backhoe? what size machine and what sized pins does it use? I have an old New Zealand made Tracgrip backhoe on a Massey Ferguson industrial tractor, which would be around the size of a Massey MF50, JCB 3CX or the big Case ones the Americans seem to use a lot. Machine weighs around 7T.
I am looking to make a mechanical thumb for it as i have some logs to pick up for fire wood. I don't have 3rd service hydraulics on the boom for a hydraulic version.
I have been trying a wooden mockup to see what fits and it is a bit tight. I was thinking of 32mm pins, at least for the connection to the dipper arm. 25mm would let me tighten up the curve on the end so it doesn't interfere with the bucket, but I don't want anything to bend.
It has a fair amount of power and is not a home gardener machine, although most of the work recently has been in the garden. No mucking around when it comes to power gardening tools around here

 

[Pete.]

You don't see them used over here in the UK. I've seen plenty of the fixed type which have just a brace but I've never seen a hydraulic thumb in use over here, not in construction anyway.

 

[addjunkie]

You can buy hydraulic thumb kits, some quote sizes etc.

An example

Raptor 900 Hydraulic Excavator Thumb - 4 to 6 tonne

Raptor 900 Hydraulic Excavator Thumb - 4-6 Tonne The 'Raptor' hydraulic excavator thumb grabs are available in a range of sizes, to suit 1 to 25 tonne excavators. They are designed to work in conjunction with standard attachments such as digging buckets, riddle buckets and land rakes and will...

www.jbequipment.co.uk

 

[GRW]

Couldn't you just hang a maual log grapple off your excavator arm?
Something along these lines....

VEVOR VEVOR Timber Claw Hook, 28 inch 4 Claw Log Grapple for Logging Tongs, Swivel Steel Log Lifting Tongs, Eagle Claws Design with 2205 lbs/1000 kg Loading Capacity for Tractors, ATVs, Trucks, Forklifts | VEVOR UK

Get the VEVOR Timber Claw Hook for efficient log transport! 28 4-claw design, 2205 lbs loading capacity, fits all vehicles. Sharp hooks, heavy-duty steel, and 360-degree rotation for your toughest jobs!

m.vevor.co.uk

 

[8ob]

Who has a thumb on their excavator or backhoe? what size machine and what sized pins does it use? I have an old New Zealand made Tracgrip backhoe on a Massey Ferguson industrial tractor, which would be around the size of a Massey MF50, JCB 3CX or the big Case ones the Americans seem to use a lot. Machine weighs around 7T.
I am looking to make a mechanical thumb for it as i have some logs to pick up for fire wood. I don't have 3rd service hydraulics on the boom for a hydraulic version.
I have been trying a wooden mockup to see what fits and it is a bit tight. I was thinking of 32mm pins, at least for the connection to the dipper arm. 25mm would let me tighten up the curve on the end so it doesn't interfere with the bucket, but I don't want anything to bend.
It has a fair amount of power and is not a home gardener machine, although most of the work recently has been in the garden. No mucking around when it comes to power gardening tools around here

We use them, you will be better off with the geometry allowing the thumb a full 180 degrees of movement, a lot of what you will try to pick up will have rolled off the bucket by the time it gets to a 90 degree thumb. Try to make it a hydraulic action if you can, much easier to use.

Bob

This is one on our six ton machine

 

[sako243]

What about simply reusing the pin on the dipper for the pivot point? Just needs a longer pin. A friend did something similar for a log splitting attachment. A fixed plate welded to the tipper arm that had a pin fitting and then used the existing pin (but lengthened) for the attachment (in his instance that was fixed).

With respect to hydraulics you could install an electric diverter valve onto one of the rams (maybe bucket curl) so that you can hold a button and then curl the bucket to activate the third function.

You don't see them used over here in the UK. I've seen plenty of the fixed type which have just a brace but I've never seen a hydraulic thumb in use over here, not in construction anyway.

The Americans don't seem to have caught up with us Europeans on things like the EngCon and other brands. There's a fair few videos about on GazTube where they are blown away by the system whereby they "we" push a button in the cab and can quickly swap the entire implement over hydraulics and all without having to get out of the cab.

A fair few of them seem to be concerned over the loss in breakout force and that's the reason they don't like them. However for 99% of the time it doesn't matter as machines are overly specced and the ones that are running that close to the limit tend to be quarry machines where you don't need to swap over.

 

[sako243]

How would one go about making one for an extending dipper arm then? One would be very handy for me (hydraulic) but there isn't a lot of space between the end and the main dipper. Guess it'll have to be a short stubby put powerful ram.

 

[Pete.]

I'd ask myself how often do I expect to need to use the thumb with the boom extended? Far better to fix the thumb to the main boom and pull the work in with the bucket before grabbing, then you'll not have dangly hoses to worry about either.

 

[Memmeddu]

The smaller excavators and backhoes I see at work use 40mm pin some cat use 41mm

 

[dieselsamurai]

This is another on my project list , i have the pipework on my digger and the electric diverter valve steel etc just way down the list!

I would want it removable though as have dug a lot of deep soakaways and even the bracket welded on could get in the way i feel certainly on a 1.5 ton machine like mine

Was looking for something else on here yesterday and came upon this



but like @sako243 says better to use the dipper pin as a pivot point but I may use this idea to mount the ram or as below a much longer ram



One thing you have to remember on most decent thumb kits there is a pressure relief valve set just below main valve block pressure relief so that you dont over pressure when grabbing stuff , also means you can pick something up and curl it in without needing to match the thumb to the bucket as you do

 

[sako243]

I'd ask myself how often do I expect to need to use the thumb with the boom extended? Far better to fix the thumb to the main boom and pull the work in with the bucket before grabbing, then you'll not have dangly hoses to worry about either.

Quite often is the answer. It saves having to move all the time and we've got big banks etc., around the place so the use case would be reaching down to pick bits etc. I wouldn't want to take the machine down them if I don't have to.

 

[Pete.]

Quite often is the answer. It saves having to move all the time and we've got big banks etc., around the place so the use case would be reaching down to pick bits etc. I wouldn't want to take the machine down them if I don't have to.

Ok but surely if you have a bucket and thumb you can crowd the item towards the thumb, retract the boom and then you have it? Another advantage of having the thumb fixed on the main arm is you can boom out a bit and reach around over-sized stuff.

 

[8ob]

Ok but surely if you have a bucket and thumb you can crowd the item towards the thumb, retract the boom and then you have it? Another advantage of having the thumb fixed on the main arm is you can boom out a bit and reach around over-sized stuff.

I agree, you could extend the pins on the bucket/crowd and fabricate a thumb bracket that went over them.

Not to scale

 

[Pete.]

That wasn't exactly what I meant but it's a handy solution. The way I see it, one of the biggest PITA's of having a hydraulic thumb on a telescoping arm is the bloody hoses will dangle all over the place when the boom is retracted. I had a rotating clamshell supplied on a 8 tonner with over-length hoses last year and it was a real nuisance.

 

[sako243]

@8ob where would you put the base of the ram then?

@Pete. The simplest I see for the hoses is either to route them where the bucket ram hoses go because those are run along guides on top of the boom, that could tap into the hammer / 3rd service or do as I suggested above and put an electric diverter valve onto the bucket ram. That way hoses would be short. Yes you can't curl both thumb and claw simultaneously but I can't see that being a major issue if it's just a button on the joystick ala Quicke loaders etc.

 

[Agroshield]

Here's one which works with the extradig:

Inside Extendible Dipper Stick Hydraulic Thumb - AMI Attachments®

www.amiattachments.com

Another one here. Hopefully having the machine, you can figure out how and where it would fit:

JCB Hydraulic Thumb

JCB Hydraulic Thumb to Suit JCB 3CX We bought this with a new 3CX but it has only been used once, and has been in the shed for a while as we have bigger machines with grabs now that tend to do the work, and the jobs it was intended for slowed down once we bought it. It’s designed so it can be...

www.planttalk.co.uk

There is also a fixed one on eBay, but it looks iffy - there are three pictures, one of the attachment, one of a JCB with a different thumb fitted and one of a different machine (https://www.ebay.co.uk/itm/180837377288).

 

[prepman]

Who has a thumb on their excavator or backhoe? what size machine and what sized pins does it use? I have an old New Zealand made Tracgrip backhoe on a Massey Ferguson industrial tractor, which would be around the size of a Massey MF50, JCB 3CX or the big Case ones the Americans seem to use a lot. Machine weighs around 7T.
I am looking to make a mechanical thumb for it as i have some logs to pick up for fire wood. I don't have 3rd service hydraulics on the boom for a hydraulic version.
I have been trying a wooden mockup to see what fits and it is a bit tight. I was thinking of 32mm pins, at least for the connection to the dipper arm. 25mm would let me tighten up the curve on the end so it doesn't interfere with the bucket, but I don't want anything to bend.
It has a fair amount of power and is not a home gardener machine, although most of the work recently has been in the garden. No mucking around when it comes to power gardening tools around here
View attachment 479273View attachment 479274

Fitted one to my digger...worth it's weight in gold!

My missus cleaning the bath, after my monthy bathtime,