Cat 307

[Anonymous Poster]

Just bought a Cat 307 excavator, used 97. I've used some bigger ones before, but I think this will get the job done around my spread, /forums/images/graemlins/grin.gif . It's in the #15,000 class. Anyone got experience with one of these particular models? How about a good source for a mech. thumb? Lots of tree and stump work ahead. thanks...

 

[Taylortractornut]

I use a 307 and a 312 Excavator alot for a freind of mine, we clear land and dig pools. I m used to rnning a 300 Komatsu with a 35 to 40 foot reach sometimes it seems that the 307 is small but there are a good sized machine around the houe and in town. Does your 307 have the side shift boom and blade, They are both pretty handy. Im getting set up now to build thumbs as a side income, I build a few every winter. I bought a pattern torch a few weeks ago and the next time im i think about it ill measure the thumb on my hoe at work. I do alot of demolition work and built a thumb for my old Ford backhoe and its been the best investment yet. Take care Taylor Lambert

 

[ScottAR]

Just type in excavator attachments into your favorite search engine and you'll have more sources than you can look at.

 

[Anonymous Poster]

I would highly recommend not putting a mechanical thumb on an excavator. For a backhoe, it's fine, but not for a trackhoe. Get a hyd. thumb. They're 100% nicer to use. The only reason you don't find them on backhoes as often, especially older models, is that it takes more to have a hyd. thumb so that you can operate it along with another function at the same time and not have a slow down, excavators are different and as you know, you can run many controls at once. Get a hyd. thumb, it allows you more odd ball ways to get at something rather that depending on the bucket's movements to control the thumb's.

Blake
WA

 

[Taylortractornut]

Blake I belive what he means by mechanical thumb is a stiff adjustable leg thumb. they have a few advantages such as quick attachment and disconnect lots cheaper if you dont have auxhilary hydraulics installed to. I put a hydraulic thumb on a freinds 790 Deere cost about 4200 dollars in material and another 500 t o have the lines bent. THe thumbs removability has alot to do with truck loading with the thum attached even folded back you burn more fuel trying to pull its weight and the dirt, also cuts down on the reach of the machine with the thumb when loading trucks. I think the 790 uses 5 to 10 percent more fuel with the thumb attached.

 

[Anonymous Poster]

</font><font color="blue" class="small">( also cuts down on the reach of the machine with the thumb when loading trucks. I think the 790 uses 5 to 10 percent more fuel with the thumb attached. )</font>

What do you mean by the reach of the machine?" I don't really see how the thumb can get in the way if it's tucked back. If you have the right one, it should be nice and snug against the dipper. Now, when the machine will have trouble loading trucks, what size is it? Is it the size of a JD 120 or 490E? I don't know cat real well. /forums/images/graemlins/crazy.gif I just think that for what's it's worth, you buy the hyd. thumb, yeah it's pricey, but you easily pay for that with the jobs you'll do, not including more of a variety due to a thumb on the machine. Taking a thumb on and off to me is a waste of time. Those are just opinions, I'm curious to see what you say.

Blake
WA

 

[ScottAR]

A JD 790 is about a 35 ton rig... a big boy...

The loading trucks part likely has to do with the bucket curl. At max curl, the thumb will displace dirt. A loading bucket will have a fair heap on top.

 

[Anonymous Poster]

Thanks for the advise all. I was thinking of the mechanical due to the price, also one less hydro line. This one has the straight boom, no blade. It was hit or miss. I called on several, scattered across this country and elsewhere. I had to buy close because some shipping would have cost a quarter the price of the machine. I was just trying to find a decent machine at a decent price. I originally was looking at the earlier E70s. Then I found this at a slight higher price, newer machine and model, close by free shipping. Seems like a good honest dealer, pointed out vibration I didn't even notice. Also giving a month on any major mechanical problems I may encounter, more than I expected. He's checking vibration before the sale is finalized. Thanks again for all your responses. /forums/images/graemlins/smirk.gif

 

[Taylortractornut]

Blake alot of times wehen loading with a hoe and you have the thumb folded back any you have a full bucket of dirt and the boom and stick extended all the way out the wieght of the thum can make it more unstable. Next time your boss has his thumb on his backhoe with a rock or a bucket of materil and swing it over the side and have him let the boom down kinda swif t and bring it to a stop, It more than likely will want to lean up on its outrigger a bit. I had that happen in a 690 JD loading trucks with the thumb folded back. i was on a hill loading a dump truck and when i swung my boom over the truck and boomed down a bit for more reach i leaned all the way over and broke a few good sized holes in the beds bottom. wthe way the cut was i had d to swing over the side of my tracks to load the trucks insted of have my tracks in line with the trucks. In a crane or excavator you can always pick up more over the front or back of the machine than the sides if the slew ring is in the center of the carbody.

 

[Anonymous Poster]

I see what you're saying. I've operated his backhoe with a heavy rock and have had the machine want to lean way out there lifting the right side (if swinging to the left) up a little. But all you do is ignore it, becuase it won't go far, or if it's really bad, just raise the side you are swinging to the most. I just think, personally, that for an excavator, it's worth it to have a hyd. thumb, yeah you may displace some dirt with the thumb there, but think of all the advantages you have a hyd. thumb rather than a mechanical. There are many times when I wish the thumb on my boss's backhoe was hyd. just because of the freedom without the bucket controlling the thumb. Also, a lot of mechanical thumbs seem to be stiff, straight. A hyd. thumb is curved and that makes for nice fit on an object. My boss's is one of the few designed mechanical thumbs that is curved.

Blake
WA