Bushhogging Basics

   / Bushhogging Basics #1  

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I'm sure some of us newer tractor owners would appreciate some pointers from the experts on proper bushhogging techniques. I have several questions

1. While BHing, is the "tail wheel" supposed to be carrying the weight of the cutter? Or does it ride just above the ground?

2. With at least 3 adjustment points (Tail wheel, Top link, Lift arms), is there a simple solution to adjusting the height of the cutter? Or do you just "play around" till you get it right?

3. My unit is an "Agri Four" and it is loud!! It sounds like it's going to fly apart. Shaft is straight and U-Joints are lubed. Sounded like that at the dealer and he didn't flinch. Any comments?

Thanks to those who have helped so far,

Rick
 
   / Bushhogging Basics #2  
1) I have the tail wheel on the ground.

2) LOL! I "play" around! Actually, I set up on a fairly level spot (driveway) and "eyeball it level fore and aft as well as laterally. Although there is adjustment in the tail wheel, I never touch it...top link pretty much does it all for me.

3) Yep...wear ear plugs or muffs!

I borrow a 48" cutter from a friend to mow about an acre twice during the season, so I'm no expert. The area is mostly vines and brush...nothing too heavy. As it doesn't belong to me, I prefer not to do any adjustments on the cutter. As set, it cuts to about 3"-4" high. Good enough for my purposes.
 
   / Bushhogging Basics #3  
<font color="blue">…is the "tail wheel" supposed to be carrying the weight of the cutter? Or does it ride just above the ground?...</font>

The rear wheel supports the rotary cutter and will be in contact and ride on the ground…

<font color="blue">…2. With at least 3 adjustment points (Tail wheel, Top link, Lift arms), is there a simple solution to adjusting the height of the cutter?...</font>

Normal cutting - The front end of the cutter should be 1 – 2 inches lower than the rear, with the front skid plates “gliding” in the air 3-4 inches above the ground surface… (actual height will depend on terrain, rocks and boulder terrain usually being the highest) This position uses the least tractor’s PTO hp… (most efficient!)

Mulching/grinding cutting – The front end of the cutter will be level or 1 – 2 inches Higher than the rear, keeping the cut debris “for a longer period of time” in the cutting path of the blades, generating a “mulching” action of the debris vs just “shearing” action. This position requires the most PTO hp action to sustain operation.

Most tractor’s position controls will have a “lock/stop” you should adjust to prevent the cutter from riding into the ground or on the surface. (When traversing streams/creeks, short fast changing ground terrain, etc. you will bring the cutter into the transport position and then need to lower it “quickly” back to normal terrain… is where this position lock/stop is mostly used)

<font color="blue">…3. My unit is an "Agri Four" and it is loud!! It sounds like it's going to fly apart…</font>

Most rotary cutters are nasty sounding to begin with… /forums/images/graemlins/blush.gif ( also God’s reminder of how dangerous and unforgiving they really are…)

Just verify your blade bolts and pan assembly are torqued to the proper spec’s, your gearbox is properly mounted to the deck, and your PTO drive shaft male/female sections are synchronized (if not it will vibrate/shake and be ultimately dangerous… and cause mower fasteners to vibrate loose and “fly apart”…/forums/images/graemlins/shocked.gif)
 
   / Bushhogging Basics #4  
John just gave an excellent summary of the adjustments, but there is one further detail. The top link (or chain) needs to be slightly slack when the cutter is in the level working position. This allows the cutter frame to attempt to follow the contour of the ground as the tractor passes over undulations. Of course when traversing very sharp changes in grade there may not be enough "slack" and the cutter will either gouge into the ground or be pulled up in the air higher than desired.

On many cutters this is provided for by a short link between the cutter mast and the connection to the top link. Some others use a slotted arrangement or chains to the rear. Some people just use a chain instead of a solid top link, but this allows the cutter to flip way up if its front edge strikes a tall stump so it is not as safe and may damage the PTO shaft.

One further point. Most tractors have "position control" that allows you to return the 3 point linkage to the same "down" position every time you lower it. This is how you maintain the height of cut at the front of the BH. However, there may be "leakdown" in the hydraulics that allow the cutter to slowly sink and therefore not maintain a level cut from one end of the field to the other. Some tractors have no position control on the 3 point hitch. For those there is a simple solution in the form of "check chains" (an accessory available in most Farm Supply stores) that limit the amount the draft links can be lowered. These attach to the tractor top link pin and run diagonally down to the connection pin on the rear of each draft link. So for this situation, the front height of the cutter is adjusted by selecting the proper links in the check chains and then just lowering the hitch until the chains are tight.

Hope this helps.

JackIL
 
   / Bushhogging Basics #5  
"Just verify your blade bolts and pan assembly are torqued to the proper spec’s"

This is an extremely good point. Torquing (and the use of anti-sieze compound) ensures not only the unit stays together...but also that you can disassemble it when the time comes for maintenance. But you do want to check the torque (to ensure they aren't loosened by vibration) every so often. A unit like a rotary cutter...I'd check before each use. The cutter I use, a Deere 413, isn't used by anyone else (just can't talk the current owner into selling it to me), so I check the torque prior to using it...got to borrow a torque wrench to do it....the bolt is around 200 ft-lb, if I recall correctly. My wrench only goes to 140 ft-lb or so.

Use your airgun to remove fasteners, friends. Use your torque wrench when you're assembling them!
 
   / Bushhogging Basics #6  
For the best cutter positioning under most situations I'd suggest you do a search of TBN under the subject of "check chains". There is a great deal of useful information under the many posts you'll find as well as a few photos.
 
   / Bushhogging Basics #7  
<font color="blue"> However, there may be "leakdown" in the hydraulics that allow the cutter to slowly sink and therefore not maintain a level cut from one end of the field to the other. </font>

Yup, this is true - I've found that the "leakdown" process can be slowed by setting the valve that controls how fast the 3PH to the "Closed" position. Seems to prevent the 3PH from dropping as fast. On the other hand, that makes it a bit tougher to drop it when you have to adjust it...

Oh, keep the wheel in back on the ground at all times, especially when going up a hill. If you have lots of weight in front you will probably be OK, but if you get light in front it is quite possible to flip the tractor on its back, with you under it. This is one of the more common ways people kill themselves with a tractor (a fun tool, but also a pretty dangerous one if not used with great care).
 
   / Bushhogging Basics #8  
OK, you have arroused my curiosity about leakdown. My 3pt leaks down very slowly after I kill my engine. However, as soon as I restart it, the 3pt goes right back to the original position and stays there as long as the engine is running. Are you saying yours drops even with the engine running?
 
   / Bushhogging Basics #9  
John,

Thanks for the tips.

froggy
 
   / Bushhogging Basics #10  
<font color="blue"> However, as soon as I restart it, the 3pt goes right back to the original position and stays there as long as the engine is running. Are you saying yours drops even with the engine running? </font>

I don't have position control, so mine doesn't return to a previous height. But yes, when I'm bouncing around the field I think that I do get a bit of leak down even with the engine running. I know that every so often I have to pick the deck up. I suppose it is possible that I bump the lever by accident and don't realize it, though. /forums/images/graemlins/confused.gif
 
 
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