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Show Me Your 'Thumbs!'

Hendrik

Senior Member
Joined
Mar 5, 2009
Messages
1,232
Location
Adelaide South Australia
How do the hydraulic thumbs work, are they on an electric circuit? I've only been around the stationary ones, and they're a pain to use.
Generally they use the auxiliary circuit, designed for running attachments like hammers etc.
Some machines do not have this and another circuit is plumbed into the hydraulics.
 

case9030b

Well-Known Member
Joined
Aug 4, 2009
Messages
75
Location
australia
Thumbs are great for demo,I like my rake...
 

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Errol

Active Member
Joined
Jun 29, 2009
Messages
41
Location
Kamloops BC
I, too have been watching this thread to get ideas as I built my thumb last winter for my 6 tonne excavator. Here is what I came up with. I decided to put a "flat" across, instead of fingers so I could pick up small trees out by their roots more readily. (easier to let them go without tangling)

The trickiest part was figuring out where to get the fluid from. I tapped into the boom shift circuit with a 6way soleniod diverter valve. To make it easier, I just put it on the side of boom (see at top of boom lift cylinder) on a bracket.
 

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tootalltimmy

Senior Member
Joined
Aug 16, 2008
Messages
397
Location
Okanagan Falls B.C. Canada
Looks like it works well for you Errol. I have thought about putting a piece of grader blade across the thumb fingers to make it easier to pull out small trees etc. I haven't done it yet because I would like to make it removable. The fingers do come in handy for snapping long trees into shorter lengths.
 

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Errol

Active Member
Joined
Jun 29, 2009
Messages
41
Location
Kamloops BC
Tootalltimmy, it was built for a special requirement.

There are bug killed trees mixed in with green trees. It allows me to reach in and grab a tree and pull it out causing minimum damage to the surrounding trees. Like you said the small trees can be taken care of easily.

Because the machine is small, any tree over 5 or 6" still has to be pushed over first and dragged out. But the flat thumb seems to grab the root ball no problem.

The flat makes it easy to break the longer trees for piling.

Of course if it were a normal land clearing job, then the brush grapple would be the way to go.
 

tootalltimmy

Senior Member
Joined
Aug 16, 2008
Messages
397
Location
Okanagan Falls B.C. Canada
Errol. Are you working on your own property, customers, or forestry? I would like to get some paying work like that. My picture is on the son- in laws property. Lots of work but no money!
 

Errol

Active Member
Joined
Jun 29, 2009
Messages
41
Location
Kamloops BC
Interesting boom setup.:)

Ya, 245dlc, the boom was interesting to me too. I soon realized how handy it can be, and am using it more and more as the hours accumulate. I didn't use the feature at first, but now it's becoming automatic to me. The boom can side swing enough to dig a 7 foot wide without tracking. I'm also using it in ways helpful to the job at hand. Here I'm snaking through to push over a dead tree without killing the little green ones. The hole here by the fence could be squared off by tracking, but the offset boom made it a bit quicker.
Ya, tootalltimmy, the dead tree job is my own, 2 acres done, 90 acres to go.
 

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Mr.Mel

Member
Joined
Apr 23, 2010
Messages
16
Location
Kent Ohio
A Couple of points about thumbs if I may.

I am going to break up my points on a few posts as I am not sure if there is a maximum size allowed.
I have worked for a U.S. Attachment manufacturer for 28 years that builds an array of product for Loaders, Dozers and Excavators and our product line includes standard as well as custom attachments. I have been doing this a long time and am proud to say I do not know everything and admit I never will as a day does not pass that I do not have a new scenario thrown at me. I am keeping my company name anonymous as I feel forums are for the exchange of information not for selling product or diverting attention towards our particular product. When forums become too much like commercials they lose there appeal very fast. I am always wary when a poster names companies as there can be questions about their allegiance and motive. Certainly not in all cases but it happens.
I have been visiting this forum for a number of years to learn from those of you who post as to what you need and what you do out there in the real world. And of course as is always popular, how you guys have broke it!! I have literally taken printouts of pictures and comments from this forum to our engineers and fabricators to use for input. Great job to all of you posters out here.
One thing I have learned is what is best for one person is not going to be best for all. So do your homework before you buy regardless of the number of people that agree one thing is best.
OK, enough of the BS I did not intend to be long winded.
I talk to people and sell thumbs throughout the US and think I have noticed some trends.
Mountain Time zone progressive Link style seems prevalent and preferred. Not a large percentage of machines have thumbs installed. West of the Rockies almost every excavator has a thumb installed and they are literally 100% Progressive Style. In the Southeast U.S. if a machine has a thumb installed chances are it is Direct Connect, Progressive style is catching on. New England, they go back to Progressive Style. Much to my frustration In the Mid West they say “what are thumbs”! Again this is all in general and there are exceptions to all but this just validates that what is best for one is not best for all
 

Mr.Mel

Member
Joined
Apr 23, 2010
Messages
16
Location
Kent Ohio
Let’s get to the meat and potatoes.

Pin-On Thumb= The thumb ears straddle the outside of the bucket or coupler ears and a longer main pivot pin goes through the thumb ear, then the bucket or coupler ear through the stick and back out the other side. This is opposed to a weld-on “Generic” thumb that welds entirely to the underside of the stick. Pin-On Style thumbs can be Direct Connect or Progressive style, these both allow the bucket and the thumb to rotate on the same arc allowing better control of grip.
A major factor in thumb fabrication is the stick length on the machine. Picture this; a longer stick means a longer thumb cylinder can be installed. A longer cylinder means to an extent more travel for either type of thumb. Yes typically a progressive link style will always have more travel, we call it Rotation, but in some cases very little is gained. When we build a thumb we always need the stick length to verify the fit. Typically thumbs have one less tooth than the bucket to allow the thumb teeth to lace with the bucket teeth. Thumbs are built to a length based on the bucket or bucket /coupler tip radius. Sometimes the longer the tip radius the more chance there is for the thumb to make contact with the machine boom when retracted. Again this is where the machine stick and bucket dimensions come into being a factor of achieving a correct fitting thumb.
Another important factor is thumbs are always built longer when a coupler is installed to the machine due to the longer tip radius created by a coupler. If you are considering adding a coupler to your machine do it before or in conjunction with adding the thumb. Otherwise if you add a coupler later the thumb will be too short. I have seen thousands of dollars wasted by not following this sequence.
 

Mr.Mel

Member
Joined
Apr 23, 2010
Messages
16
Location
Kent Ohio
Progressive vs. Direct Connect thumbs ,

Progressive Style = the thumb cylinder attaches to added linkage provided with the thumb , much like the OEM bucket idler linkage, in turn that linkage then connects to the thumb body. Some New Style Progressive Thumbs are currently out that use a universal type "Rocker" Linkage.
Progressive Style Thumb Advantages = In most cases added thumb travel or rotation is gained with Progressive Style. Some companies will claim added clamping pressure is gained, our computer models do not support that claim and I would not say it or buy it. I feel an overlooked advantage to Progressive is with the linkage used between the cylinder and the thumb the cylinder is pushed further up the stick keeping the cylinder rod out of harms way. Your expensive cylinder is not exposed to rocks, dirt, mud and water as much as the Direct Connect style would be.
Progressive Style Drawbacks = Higher purchase cost, added weight, additional moving parts and pivot points needing maintained. Linkage parts on some thumbs are machine specific and may not be readily available. Progressive Link is only available as hydraulic operating.
Direct Connect Style = the cylinder attaches directly to the thumb body.
Direct Connect Style Advantages = Less expensive, Less moving parts. Less weight, Sometimes fits shorter sticks progressive thumbs will not. Direct Connect is available in mechanical, also called Stiff-Arm style. (No hydraulics required on the machine for Stiff -Arm = less $$)
Direct Connect Style Drawbacks. Cylinder more exposed to damage, may be less rotation or thumb travel.
 

Mr.Mel

Member
Joined
Apr 23, 2010
Messages
16
Location
Kent Ohio
Hydraulic thumb operation

Hydraulic thumb operation will require the machine to be plumbed by the OEM or with an aftermarket “Wet Kit” and there are options for controlling the thumb using a Joystick or a foot pedal. A thumb will not operate on a Hammer circuit as that is one way flow and two way flow is required. Some ”Combo” kits allow the selection of either type of flow to operate thumbs or hammers. Thumb hydraulic circuits are typically set to a lower pressure than the bucket circuit. What must happen when the thumb and bucket are opposing each other under pressure is the bucket must always be able to push the thumb. Thumbs for Dummies Hint, this is how we keep you all from breaking expensive things!
 

Mr.Mel

Member
Joined
Apr 23, 2010
Messages
16
Location
Kent Ohio
Thumbs Used with Various Attachments

A trend we are seeing more of these days and it offers the best of both worlds, is equipping machines with a coupler and a thumb, with the coupler a bucket and a rake can be exchanged on the machine. The thumb can be used with the bucket when you want to contain and load material and the rake used with the thumb as a “grapple” for picking and sorting applications. Once a user in general and Multi-Task applications has this combination in their arsenal they will never, never have a machine without this arrangement again. Of course the thumb can at anytime be fully retracted and digging performed with the bucket. Make sure your thumb is not wider than your narrowest bucket for obvious reasons.
Packages, while I will be the first guy to save a buck where I can you should also consider buying attachments as a “Package” made by the same manufacturer if possible. We know that as the example I have mentioned a bucket, rake, coupler and a thumb must all be made to be compatible with each other to achieve best fit and function. If you try to equip a machine with a brand “A” Thumb, brand “B” bucket and brand “C” coupler and who knows whose rake all will rely on each other for fit and function. I am being honest attachments makers are in competition with each other. We do not call each other and swap drawings and dimensions of our products no more than you call your competitor for input on bidding your jobs. Thus when all products show up for installation they probably will not match exactly and the cutting torch comes out. The result is the installation time is lengthened, the installation is compromised in efforts to get the job done and you are left with the effects. Also when warranty time comes and there is an issue you now have too many players in the picture claiming the cause is always the other manufacturers fault and not theirs. You and the dealer are stuck in the middle. So ideally buying bucket, coupler, rake, thumb from as few manufacturers as possible takes the finger pointing out to the equation. When it comes crunch time to pull out the checkbook do not waiver, it is not worth saving a few bucks to have those types of headaches and delays. You probably did not buy the cheapest machine on the market so why buy the cheapest attachments to work with it?
 

Mr.Mel

Member
Joined
Apr 23, 2010
Messages
16
Location
Kent Ohio
Finally to wrap this up. Observation #2

Finally to wrap this up. Observation #2, equipment dealers tend to focus on machine sales which = higher profit and commissions. The attachments to go on the machine many times are an afterthought or almost annoying detail to their higher dollar machine sales. Thus dealers tend to install particular attachments for reasons such as “That is what we always put on that model”, “that is what we had out back in stock”, and “my Brother In-Law knows a guy whose neighbor’s cousin builds these in his garage.” I am not knocking dealers and this does not mean your dealer is bad, just human. The rule of “The Path of Least Resistance” seems to apply. Keep in mind a number of OEM equipment brands have relationships with attachment makers as well as some OEM’s own attachment companies. Again this means there is pressure applied for the dealer to sell specific brands and types; these may not be the best for your needs. I recommend again, you do your research, call attachment manufactures directly if you have questions your dealer is not able to answer and insist that you are going to buy what is best for you. Hopefully you will buy from me but you may buy from my competitor, either way you will be better off in the long run.
I hope this information helps in your future choice involving thumbs! Sorry to have been so long winded about the topic.
Thanks all for your input on this forum, I look forward to learning more from you all in the future.
Mr Mel
 

CM1995

Administrator
Joined
Jan 21, 2007
Messages
13,246
Location
Alabama
Occupation
Running what I brung and taking what I win
I am keeping my company name anonymous as I feel forums are for the exchange of information not for selling product or diverting attention towards our particular product. When forums become too much like commercials they lose there appeal very fast. I am always wary when a poster names companies as there can be questions about their allegiance and motive. Certainly not in all cases but it happens.

Welcome to the Forums Mr Mel!:drinkup Thank you for respecting the rules and atmosphere here on HEF. Glad to have you here.
 

cps

Senior Member
Joined
Jul 13, 2008
Messages
811
Location
Ireland
Occupation
plant mechanic
Great info there mr mel, i will drop you a pm sometime (when i got time to) with a few questions!

Cheers CPS
 
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