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Understanding feller buncher hydraulics

Started by air1514, March 25, 2020, 12:54:58 PM

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air1514

Hi guys.  I'm not asking for a complete hydraulics course, but I would really appreciate if someone can educate me on a few hydraulic questions I have about my feller buncher.   It's a timber king tk350. Same as a hydro axe 570 except with a cat engine. The specs say that the hot saw has 26gpm flow and the gathering arms have 41gpm flow.    My question is- why do the gathering arms need so much more flow than the saw?    It seems to me that the saw would greatly benefit from higher flow.  And I'm actually wanting to put some kind of mulcher brush hog mower on it instead of the feller buncher saw.  The saw flow isn't enough for a mulcher of any kind . But if I combined the flow from saw and arms together, that would give me the flow I need. But I might over heat the system because the gathering arms aren't meant to be running constantly. I was wondering if I could fix that issue by only giving the additional flow when needed with the foot valve that works the arms already.  Thanks in advance for any and all help in helping me understand why this will or won't work. 

nativewolf

The older hydro axe  are not really the thing for a mulching head, not enough flow as you mentioned.  The pumps and entire system just are not up to spec.  If you have a lot of mulching a purpose built machine is a better option in my opinion.  A newer feller buncher with high flow rates work fine too, they are common out west running massive FAE and Fecon heads.  
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Southside

The 26 GPM seems low to run a saw.  A shear yes, but for a saw that does not seem right.  Even my LT70 is at 18 GPM and IIRC my Franklin 5000 is in the 80 GPM range for the saw pump.  Can you get any #'s off of the saw pump itself and try to see what your machine is actually putting out?  You might be able to get the #'s off of the saw motor and look up the ratings for that to put you in the ballpark.    
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mike_belben

Find your mulcher and mount a pony motor to run suitable hydraulics.  Leave the machine as is.
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nativewolf

Quote from: mike_belben on March 25, 2020, 11:38:34 PM
Find your mulcher and mount a pony motor to run suitable hydraulics.  Leave the machine as is.
Yep, another good solution.  
Liking Walnut

Riwaka

Hydraulics can be expensive. Use the pony motor mounted on the mulcher through something like a twin disc clutch/ pto unit (or fluid coupling) to a belt driven flail/ tooth drum mulcher.
Fuel tank can be a bit small as a downside
Radio control the motor with on/ off and a few engine rpm range settings. Generator specification industrial engines can have heavier flywheels for constant rpms.  The pony motor's radiator needs good protection screens / cleaning. (see how kobelco excavators keep their rads clean ) Batteries from the vibrations use marine rated batteries.
CSI | Remote Power Unit 6500  (as an example of a radio controlled motor) also chambers delimbinator.
The feller buncher still has its full hydraulic capacity to raise/ lower the arms and steer etc, not cooking the machine's hydraulic oil etc.

Would need to price engine/ mulcher set up against something like a rayco 100, supertrak 140/170, ag tractor mulcher conversions etc

air1514

Those are some good ideas. Now I have more research to do. Thanks 

kiko

I have a saw pump off a Prentice buncher of the same vintage as your Timberking. It is 74cc/rev displacement pump which equates to about 42 gal/min at 2200 rpms.  I am currently doing the same thing you are doing.  I have a Tigercat 726b and a fecon bh250 I am going to install on it .  I am having to make adapters to pin the head.  I plan to do just what you are thinking about.  I plan to run the mulcher off the saw pump and tee in one the functions I no longer need after the valves   too add flow from the implement pump when needed by applying the foot pedal.  Now if you want a mulcher with high duty cycle this wont  work. I plan to use mine for personal use.
The factory built tigercat M726 has a dedicated mulching pump that produces around 80gal/min.  If I can get 60 or so with out completely redesigning the pump system I will.  My Tigercat has the 8.3 Cummins which had stock horse power of 215 , I have bumped mine to around 265. Your Timberking is about 200hp if IRC. Horse power increases may be difficult with that electronic engine.  Here is the machine I have been building over the past couple of years. I have bought three of these machines as salvage and have made this one. Still a ways to go.


 

 


bushmechanic

When I saw this thread it had kiko wrote all over it lol! Great job on the Tigercat and I'm sure that it will work fine. Quick question, why do you want a mulcher on a wheeled loader anyway? Underbrush? Stumps? 

kiko

Around here after a timber sale the sweet gums take over fast and makes your land where you can even walk through it. I don't have the time or will to hack and squirt.  The side affect of mulching is fertile compost and things start growing back quick, but then the trails can be kept beat back with a bush hog.  The reason a buncher works well for a mulcher is that it already comes with a Forestry package.  Stumps that were made a few years prior will be easily handled esp the pine stumps.

barbender

Your stumps rot really fast down in middle Georgia, compared to up here. I remember asking about all the holes I kept stepping in- stumps duh?!😂 
Too many irons in the fire

treemuncher

From an engineering standpoint, the flywheel mass of the disc carries through most of the cut. Once the disk is up to speed, and you generally make just 1 instant cut, there is no requirement for a high flow motor to the blade. You do want the arms to act fast enough to grab the tree and not be so slow as to let it jump out of a firm initial hold. The size of the cylinders will dictate the amount of force (larger diameter = more force) and larger cylinders take more fluid flow to react faster than smaller cylinders. The pump that runs the arms is likely used for more than just the grab arms so it will be sized to handle multiple cylinders. The saw head pump is likely on a dedicated circuit so that the saw has continuous power available.

Combining pump flows is a recipe for hydraulic failure with mulcher heads. The cyclic demands are extremely punishing on the pump system. I know, I've been through quite a few. Filtration of the mulcher circuit is paramount to long service life. My filtration cart is one of my best PM tools. If you want to build a mulcher, start off with the correct sized pumps and motor combinations with pre and post filtration.

In my general experience, anything less that 5000 psi or 50-60 gpm is too slow for productive use. Then again, not everyone wants to tackle everything in their path as required. If all you want to do is 2"-3" trees or you have lots of time, 30-40 gpm might be sufficient.  I commonly mulch trees in excess of 24" diameter so I need power and production. I normally run 100 or 120 gpm at 6500psi or 5500 psi respectively. Even these machines feel slow at times.
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kiko

Treemuncher, your points are valid.  I repair a lot of mulching machines. Most recently I have rebuilt all the pumps off a CMI 450.  It has a 250cc  Sauer mulcher pump , two 100cc pumps for the tracks and a gear pump for the cylinders. Most of the purpose built machines I have worked on have a closed loop operating the mulcher.  Combining pump flow with a closed loop would be a recipe for disaster.  I have successfully combined pump flows in open loop systems on track buncher conversations and not just initial success.   The M726 TC comes with an open center Kawasaki pump for the mulcher. Not sure how the 480 TC is set up as none if my customers have one.  Some of my customers think I am going to go into the mulching business when they find out I am building that TC up. I have no intention of doing anything of the sort.  Seems to me mulching is a low margin business.  These guys that buy a skid steer and a mulching attachment think they are making big money out of the gate, then the lack of maintenance catches up to them and it is over. As it seems you do, constant preventative maintenance is the only way to make it mulching.

barbender

Mulching guys would do well to study the maintenance and horsepower needs of an asphalt milling machine. What they're doing is more similar to that than brush mowing.
Too many irons in the fire

kiko

Tigercat made or makes an asphalt grinder model 750 I believe. Work on one some years ago.

barbender

I didn't realize that, Kiko. I guess the point that I was trying to make is that an asphalt milling machine is severe service (brutal, really). So are forestry mulchers. I look at these #10,000lb, 120hp skid steers running a mulching head and just wonder how long they can hold up.
Too many irons in the fire

kiko

Treemuncher,  that Barko is an awesome machine.  I have done service work on a 930 in the past.  I thought it to be a well built machine with a comfortable cab. Never got into the hydraulics on that machine just some electrical issues.  Unfortunately I have had to repair a few of the c130/40 rayco machines and found them to be very difficult to repair.  Had to weld cracked fuel tanks , remove the cab to access the Eaton cable operated mulcher pump for repair . And those suction strainers...

1270d

We toured tigercat a few years ago.  At the time there was a dedicated tracked mulching machine on the production line.  I believe they said it was 750hp.  Not sure what pumps they were turning but it was one serious machine

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