Brush cutter opinion/help

   / Brush cutter opinion/help #1  

D&D

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Tractor
KIoti, JD, Kubota
I’ve been talking myself into a front mounted brush cutter and exploring some options. One thing I’ve noticed is a couple of the manufacturers may not be using a cushion valve on the motor, rather just teeing the lines. One side of my brain says that can’t work very well, the other side says but you’ll save ~150 bucks.
‘This is not to berate anyone else’s build, noticed on this one and the lane shark, just wondering how the T would work. This video clearly shows the arrangement at the 14:13 mark,
 
   / Brush cutter opinion/help #2  
Yes, it's T but between both T's, there is a check valve. This check valve will allow the hydraulic motor to spin down on it's own, instead of an abrupt stop that would most likely blow the seals on the motor. It will also prevent the motor from rotating the wrong way, even though it's not usually an issue with brush cutters.

Both setups will technically do the same job, albeit in a slightly different way.

Personally, not a fan of these loader mounted brush cutters. The tractor has a perfectly good running PTO in the rear capable of delivering most power out of the engine, so I don't understand why limit it so much by going hydraulic.

About the only scenario I see this could be useful, is mowing high embankments.

In that video, what would work perfectly would be one of the chain cutters we use in this side of pond. Pretty much perfectly scenario for it.
 
   / Brush cutter opinion/help
  • Thread Starter
#3  
Yes, it's T but between both T's, there is a check valve. This check valve will allow the hydraulic motor to spin down on it's own, instead of an abrupt stop that would most likely blow the seals on the motor. It will also prevent the motor from rotating the wrong way, even though it's not usually an issue with brush cutters.

Both setups will technically do the same job, albeit in a slightly different way.

Personally, not a fan of these loader mounted brush cutters. The tractor has a perfectly good running PTO in the rear capable of delivering most power out of the engine, so I don't understand why limit it so much by going hydraulic.

About the only scenario I see this could be useful, is mowing high embankments.

In that video, what would work perfectly would be one of the chain cutters we use in this side of pond. Pretty much perfectly scenario for it.
With the check valve opening from return side, correct? Wonder why so many claim a cushion valve is the only way to stop seal blowout? GPM have an effect on which is better?
Practicality comes into play depending on how many trees/ obstacles to mow under and how much you like reversing. A boom or ditch bank mower may suffice, researching options.
Thank you.
 
   / Brush cutter opinion/help #4  
Looks like this setup uses the 3rd function, so when you release the button, both work ports of the valve are blocked.

Basically when you turn the cutter off, the inertia will turn that motor into a pump. With the check valve, the fluid will pretty much flow between just the motor and the check valve, pretty much making a small circuit up to the Ts.

The cushion valve uses two relief valves that open to the opposite side. Once there is a pressure spike like when turning the cutter off, it relieves the pressure to the other line. Using this valve, will allow for a faster slow down of the motor without blowing the seals.

Adjusting the relief valve on the return side of the motor, adjust how fast/slow it will take to fully stop the blades.

While with the check valve, it will coast down a lot longer till it finally stops.

Either way is fine really and both ways prevent the seals from blowing out.

I have an homemade flail cutter for my backhoe done with the check valve route. No issues whatsoever.
 
   / Brush cutter opinion/help
  • Thread Starter
#5  
Looks like this setup uses the 3rd function, so when you release the button, both work ports of the valve are blocked.

Basically when you turn the cutter off, the inertia will turn that motor into a pump. With the check valve, the fluid will pretty much flow between just the motor and the check valve, pretty much making a small circuit up to the Ts.

The cushion valve uses two relief valves that open to the opposite side. Once there is a pressure spike like when turning the cutter off, it relieves the pressure to the other line. Using this valve, will allow for a faster slow down of the motor without blowing the seals.

Adjusting the relief valve on the return side of the motor, adjust how fast/slow it will take to fully stop the blades.

While with the check valve, it will coast down a lot longer till it finally stops.

Either way is fine really and both ways prevent the seals from blowing out.

I have an homemade flail cutter for my backhoe done with the check valve route. No issues whatsoever.
From what I’ve been reading and seeing, the 3rd function pressure side is often used, a separate return to tank is somehow incorporated, teed before 3rd valve or direct to tank. I have a separate 25 gpm pto pump/tank combo available, was leaning towards that and just running two lines. Kinda depends on how much cutting capacity. I like the lane shark concept, beefing up to a 6” plus tree killer offset and vertical would probably require some counterweight. This setup would not be healthy for the loader arms/attach points on a compact/utility tractor.
 
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   / Brush cutter opinion/help #6  
One advantage of a hydraulic front mount brush cutter is the blades are sharp on both sides so it can rotate either direction.

Here is the new version of mine: Tree Terminator Rotary Mower

Got my 7' in 2009:
PA010008.JPG
PA010003.JPG


Still using it now:
P7210009.JPG

P7210002.JPG


The hydraulic motor has a built in cushion valve:
P4060003.JPG
 
   / Brush cutter opinion/help
  • Thread Starter
#7  
One advantage of a hydraulic front mount brush cutter is the blades are sharp on both sides so it can rotate either direction.

Here is the new version of mine: Tree Terminator Rotary Mower

Got my 7' in 2009:
View attachment 853861
You and some others here are why I’ve been pondering the thought. That one, rotated 90 degrees and stuck out ~18” would be great for horse trail cleaning. How stable would it be though? And what negative effects on the qa and boom would crop up?
 
   / Brush cutter opinion/help
  • Thread Starter
#10  
Right, all of the premade ones are 42-44” which would be slow going cutting up to 8 feet off the ground. On the flat, I know that small of cut would just be a waste of time and fuel. Hence the hesitation to do anything.
 
 
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