Excavator..manual vs hydraulic thumb

JimP · Dec 13, 2015

Hi. I have been clearing land in Conn with a Volvo ECR88 (18000 lb) excavator. If I had to start over I would look for 12-16 ton excavator with a blade (blades are less common on the full size excavators). The 9 ton excavator works well but there are limits to lift capacity (can not lift some stumps until I rake dirt off), reach (always looking to work without moving and further away from the cab) and stability (capacity is different with blade up vs blade down and up front vs over side). If you are looking to build burn piles reach and capacity at full extension with blade up will be important. Once you get the hang of the controls running a 9 ton or a larger excavator will be no different, they are very precise (and fun!). The only difference will be how much physical room you need to get into work position and tail swing clearance (zero tails are great - no swing interference but maintenance is harder as everything is crammed closer). If you will be selling when you are done look for machines that are popular in your area. In used excavators condition trumps most everything else as repairs are very expensive. The more common the machine in your area the more choices you will have in finding persons to maintain and repair.

3 inch trees you may be able to pull out stump and all. 10 inch probably not. I started by cutting the tree down, sectioning the tree and digging the stump. Stump digging time after dropping the tree varied but for larger sumps it could be 20 to 30 minutes. Now I dig three sides of the tree and push the tree over with the excavator using the undug side as a hinge. Less than 5 minutes and the tree is down, with a stump facing me. As a bonus I don't worry about tree lean and can drop the tree in any convenient direction. Chainsaw work is easier wth the tree on its side. CAUTION. Watch out for dead tops and widow makers. This type of work can be hard on excavators (and I have the broken windshield to prove it). Look for an excavator with a demolition screen and falling objets protection or one that has mounts for you to mount the screens. Also, the tipped stump is under tension and wants to flop back into the hole once you cut the trunk.

There are 3 types of thumbs. The simplest mounts the thump parts on one plate and the plate is mounted to the stick. This type has the least range of motion (points where the bucket and thumb meet) but is the cheapest. A main pin thumb pivots the thumb around a bucket pin and welds only the cylinder mount to the stick. This style has a better range of motion but is more expensive. A progressive thumb mounts to the main pin but includes a linkage to give the best range of motion. The progressive is also the most expensive and seems to be less popular on the east coast. I would look for a pin mount or progressive thumb for the range of motion. Try and make sure the thumb teeth will mesh with the bucket teeth. This helps when trying to grab smaller items.

My excavator was already pumped for auxiliary 2 way hydraulics. I had a Geith bucket so I mounted a Geith pin mount thumb. I had to adjust the auxiliary circuit pressure so that the bucket can overpower the thumb. I am happy with the Geith combo as the thumb and bucket teeth mesh and the thumb folds in tight and clears the stick and boom in use. Cost for thumb, welding and hydraulic connector lines was about 4K. If you have to add the auxiliary hydraulics cost will be much higher.

After using a hydraulic thumb for a couple years I can't imagine using a fixed thumb. With the hydraulic you can adjust the grab point to pick up anything from basketball sized rocks to small trees to large stumps. Large stumps can be tricky to grab and the hydraulic thumb allows much more flexibility in where you can grab them.

Good luck and be careful! Jim

WoodChuckDad · Dec 13, 2015

Great info. Thank you. I'm still looking. Came across a yanmar vio 75 with a hydraulic thumb, on the net that is a couple hours from my property. 17,000 lbs. don't know anything about them. I see very few excavators between 18k and 30k lbs. I have been visiting family in hospital this weekend so the only looking I could do was on line.

WoodChuckDad · Dec 14, 2015

So here is what I am up against. My price range is about 30K. Obviously a well used machine is what I am looking for. There are several 11,000 lb units with hydraulic thumb in that range. A few 13-14,000 lb units with hydraulic thumb. some 18,000 lb units....some with hydraulic thumb, some with manual and some with no thumb. and above that range there is the occasional 30,000 lb unit with 9k hours on it with no thumb or sometimes a mechanical thumb. I am wondering, from a standpoint of ownership cost, and resale, if I should even consider the 11,000 lb units. The amount of time to get things done may make it painful. The 18,000 lb units seem a bit over prices...I am seeing things along the lines of $32,000 for a machine with 6-7k hours.

Billrog · Dec 14, 2015

6 or 7 k hrs is not necessarily a lot of hrs. on an 18,000 # machine if it's been maintained and not all beat up. I've cleared a lot of land & for me 18,000 k would be the minimum for lifting and not dragging your self all over the place trying to dig stumps or boulders. Jim gave a lot of good advice. Good luck on your purchase & you may not want to buy a machine you've never heard of you get good money for a popular brand name when you go to sell and it won't take a long. I've had 5 and sold 3 of them for more than I paid all with over 15,000 hrs. with original motors but I did have one drop a valve at 12,000 hrs. I now have a backhoe with 7,000 hrs. and no plans to sell it any time soon.

JimP · Dec 16, 2015

3 to 5 ton machines are pretty popular with contractors here. They can do a lot of digging and can be moved with a dually pickup and no CDL. BUT, you want to do land clearing not excavation. That means digging but also moving logs, trees, stumps, rocks, etc. These will be much heavier than a bucket of dirt. Will a 5 ton machine be able to move the size stumps you plan to dig? You can dig septic trenches and tank with a 5 ton machine. But a house foundation might be slow as you won't have the reach to dig and dump the dirt out of the way compared to a bigger machine.

32K for a 7k hour 9 ton machine seems high depending on brand. Don't be in a rush. Take your time and find a well maintained machine with the features you want at your price. Check equipment sites like IronPlanet, Rock and Dirt and Machinery Trader (mods - sorry if this isn't allowed) to see what similar equipment is selling for. The Internet is your friend. I found my ex at a dealer 4 hours away.

The news today reported a man killed while working trees with an excavator, although I didn't see details. Excavators look tough but they are not really built to take a tree hit. BE CAREFUL!

LarJea · Dec 20, 2015

I started out with a 26,000 lb. Hitachi (no thumb or blade) to clear and build roads on my 10 wooded acres on a hill thinking I would need that because of the large rocks with the plan to sell and buy a smaller one when I got the big stuff done. Anyway when it came time to sell I found out the hard way that home owners, such as my self were not interested and because of the high hours (10,000) construction outfits weren't interested either so I sold it at a loss and bought a 12,000 lb. Yanmar with hydraulic thumb and blade (3400 hours) and realized at half the cost I could have got by with that to begin with. Not to mention a whole lot more nimble, easier to work on and cheaper to maintain. As far as the thumb, I think hydraulic would be the way to go by far.