Thumb Mechanical BH Thumb Designs

JimMorrissey · Feb 11, 2005

Gray or anybody else.....,

Would it be possible for your to post a picture of your thumb or find a similar looking thumb on the Web and post a pic?

I'd like to hear your thoughts on the good and bad points of the different designs....in your opinion. There are quite a few designs. Some are more flat with few teeth and the other extreme are the ones that are curved and have big teeth all the way up the sides with two sharp teeth on the front.

How would your ideal thumb be designed.

curtisfarmer · Feb 11, 2005

Hello everyone,

I bought a new L48 with a hyd. Thumb, haven’t gotten it yet but have seen the thumb design on exact machine. Check out addingtonequipment.com there is a good page with good pics., that is where mine is being built. Big cylinder and a 2 fang, open center type I believe. I hear flat is good for scooping dirt and debris but 2 fanged-open center is better for irregular objects like rocks and stumps. I don’t know because I haven’t tried yet. Maybe I will weld a plate in if I don’t like it, or maybe have 2 different thumbs???

Curtis Farmer

Henro · Feb 11, 2005

Here's a link ot the site Curtisfarmer menitoned... /forums/images/graemlins/smile.gif

JimMorrissey · Feb 11, 2005

Curtis,

Is the dealer welding the thumb on, or are you? My dealer said a thumb can't be welded on with a "stick welder or a large MIG welder". I forgot what type of machine he mentioned, but he did say that the steel in the dipper stick as "special". Wish I had more info, but I'm just going off a quick conversation with somebody at the dealership. My salesman was on vacation so I didn't get many details. I'm just affraid that if I specify a different type of thumb than they sell, the dealer won't take care of it if something breaks. Hopefully, if they do the welding it won't be a problem.

JimMorrissey · Feb 11, 2005

I just spoke with the gentlman that builds the thumbs. He stated that 95% of all static thumbs that he installs come back for a hydraulic cylinder within one year /forums/images/graemlins/shocked.gif He really doesn't offer them anymore, but he will build one for a customer if they require one.

His units are controlled by a foot pedal through a series of valves he installs. I like that fact that it's not on one of the sticks. The entire package is something like $2,500 or so. It looks like a really nice setup. He described "having to get on and off the machine to move the thumb pins and dig the mud and dirt out of them was not what you want to be doing while you are trying to get some work done" The hydraulic thumb was also "5x more efficient use of a person's time". The reason being that while you are doing this and that, you'll want to grab something and move it quickly then get back to the main task. The hydraulic thumb enable that.

The other consideration he pointed out that I had never really considered is the fact that his hydro thumb has relief valves that will "give" before the main hydraulic system valves go. This, he claims, will prevent damage to the hoe and the thumb when lifting heavy or long logs that might bend things due to the leverage they exert. That does make sense to me....He also claims the static thumbs are more prone to damage a machine because the don't give....Also makes sense.

So the question is, is it worth another $1,500 for a hydraulic thumb that you never have to leave the machine to operate? I guess that is a matter of how fat your wallet is. It was an interesting conversation and one that is making me reconsider the static thumb option, especially since this is the tractor that I'll own for quite a few years (honestly) /forums/images/graemlins/tongue.gif If the static thumbs weren't $1,000 or more, I'd go static. AND, no sales tax for me in NH.

PineRidge · Feb 11, 2005

$2500.00 sounds like a lot of jack to me for any thumb or grapple. I'm thinking you could make one for a lot less money if you were so inclined. If you're interested PM me and I'll give you the number of a chap that would be happy to start a new project. He just finished up cutting the steel for a grapple that we put on the front of our TC-40D.

rswyan · Feb 11, 2005

( I guess that is a matter of how fat your wallet is. )

Man. you ain't kiddin'.

I'm with Pine Ridge on this - I would think you could build a pretty nice hydraulically operated thumb for less than $2500 - even if you bought one of the pre-cut kits.

( f the static thumbs weren't $1,000 or more, I'd go static. )

CDP-Backhoe (cdp-backhoe.com) has kits ranging from $269 to $429 for a mechanical thumb. The component parts are all laser cut. The weights range from 31# to 150# and the structural components are 44W steel (similar to A36), and the pins are 1018. Shipping isn't cheap due to the weight though. If you have a source for steel and can do the cutting/welding yourself, figure you could get in for probably half that, in terms of actual monetary outlay.

A cylinder would run you less than $100, same for a valve, and hoses and fittings probably around that.

If it were me I would rather spend the money saved on some nice tools I can't build easily - like a welder, plasma cutter, or a Bridgeport.

Gary_Sharbonno · Feb 11, 2005

Jim I just installed a mechanical thumb on my Mahindra 2810 with a Mahindra 3375 BH. The thumb was a pre- assembled unit from Gearemore out of California. The model is a UAT 100. It weighs 61#. I welded it to my stick myself without any trouble using a stick machine with 7018 rods. The weather here has been raining so I only was able to see how it would grab items of different sizes. It is to soon to tell what the real out come will be, however so far it seems to do quite well. It has two different settings on the thumb. The thumb will fit 18' to 22" buckets. My bucket measures 20". After I try it out for a while I might cut about 1-2" off of the thumb tip to allow the thumb to close tighter to the bucket. Right now it closes to the bucket teeth.
Will let you all know later as I get a chance to use it. Right now I have the BH off of the machine so that I can use my phd.
Gary

JimMorrissey · Feb 11, 2005

Most of the cost is the valves and the plumbing (power beyond) out to the stick. He's got a pretty nice setup that doesn't divert full hydralic flow to the thumb, so it's not so "bursty" for lack of a better word. But you're right....it is a lot of cash any way you look at it and could be done at home, but that's one expensive hoe to be messing with (for me anyway). I have a Mig and have put some time in on it over the years, but this is different. The dealer mentioned some kind of "special steel" in the hoe that can't be welded with a stick or Mig welder /forums/images/graemlins/confused.gif

gray · Feb 12, 2005

Jim,

A hydraulic thimb is best but the cost is huge fir the use. I used 7018 rod and my thunderbolt to held mine on the Kubota hoe with no issues. I set the thumb about once every 4 hours of opperation. Not too much of an issue. You may wish to set one more often but it is not all the time.

The cdp thumb is a nice design.