Rotary Cutter Does Direction of Travel Matter?

[Folio]

My question is: why does my Frontier RC2060 cutter make a cleaner cut going counterclockwise vs clockwise?

The details: The brush hog is 60" wide, almost exactly covering the outside width of the rear tires on my JD 3032E. When mowing clockwise around the field the cutter leaves long intermittent streaks (two inches wide or more) of uncut grass on the right hand side just inside the rear tire. This means that on the second time around, I have to overlap the cut side of the field by at least a foot to clean up these streaks.

Mowing counterclockwise, however, I don't experience this problem and can use more of the mower to cut uncut grass. Is this because of natural blade rotation, or is something wrong with my cutter? Near as I can make out, I'm driving the same way in either direction.

The mower is level side to side on a concrete slab and the blades appear to be in good shape to my inexperienced eye. No serious dings I can see and no unusual vibrations on start up or running. It shouldn't matter, but the fields are flat to the naked eye, but very rough up close; lots of jostling about.

Any thoughts, ideas, and/or theories much appreciated.

 

[leonz]

My question is: why does my Frontier RC2060 cutter make a cleaner cut going counterclockwise vs clockwise?

The details: The brush hog is 60" wide, almost exactly covering the outside width of the rear tires on my JD 3032E. When mowing clockwise around the field the cutter leaves long intermittent streaks (two inches wide or more) of uncut grass on the right hand side just inside the rear tire. This means that on the second time around, I have to overlap the cut side of the field by at least a foot to clean up these streaks.

Mowing counterclockwise, however, I don't experience this problem and can use more of the mower to cut uncut grass. Is this because of natural blade rotation, or is something wrong with my cutter? Near as I can make out, I'm driving the same way in either direction.

The mower is level side to side on a concrete slab and the blades appear to be in good shape to my inexperienced eye. No serious dings I can see and no unusual vibrations on start up or running. It shouldn't matter, but the fields are flat to the naked eye, but very rough up close; lots of jostling about.

Any thoughts, ideas, and/or theories much appreciated.

_________________________________________________________________



Not theory but fact,

If you are traveling too fast you will leave
rooster tails with a rotary cutter.

Only half of the mowers actual width of cut is being
used as one blade is always following the other.


Your rotary cutter always has one cutting edge
following the other one in any direction and if you
are traveling at a faster speed the mower will leave
a rooster tail of grass that both blades WILL miss as
the prime mover is traveling at a faster speed.

The other thing is you may not be operating at the
540 RPM engine speed for the integral implement.

A flail mower does not have this issue as the cutting width
is being used to mow and nothing is missed especially with
flail shredderscoop knives.

 

[bp fick]

I thought this thread was going to talk about jet lag being worse going east versus west. :laughing::laughing::laughing: Sorry, just my warped mind.

It is, BTW.

 

[dusty3030]

Suction and overlap. If you have high suction blades and a cutter with a faster tip speed it usually doesn't matter much. Other cutters it does. The strip you are leaving is what is laid flat by your tires. Going one way your overlap is on the the side that after being pushed flat the blade is lifting back up enough to cut. Going the other it isn't.

Half the cutting width thing is bs unless you are mowing with a top fuel dragster.

 

[leonz]

Suction and overlap. If you have high suction blades and a cutter with a faster tip speed it usually doesn't matter much. Other cutters it does. The strip you are leaving is what is laid flat by your tires. Going one way your overlap is on the the side that after being pushed flat the blade is lifting back up enough to cut. Going the other it isn't.

Half the cutting width thing is bs unless you are mowing with a top fuel dragster.

Not to start an argument again,

No, it is not BS as one blade is always following
the other as only half the cutting edge is used.
The basic physics and the rotary cutters design using the
right angle gearbox for a horizontal cut is the issue.

You only have half of the cutting edge exposed for
work because it is rotating away from and exiting the
front of the mower and the following edge is entering
the arc.

 

[RickB]

Not to start an argument again,

No, it is not BS as one blade is always following
the other as only half the cutting edge is used.
The basic physics and the rotary cutters design using the
right angle gearbox for a horizontal cut is the issue.

You only have half of the cutting edge exposed for
work because it is rotating away from and exiting the
front of the mower and the following edge is entering
the arc.

The rotary cutter blade travelling with the edge towards the rear of the machine will pick up the grass run over by the tractor tire if the operator travels in the proper direction (this side of the cutter towards the cut part of the field). That ensures that the blades are cutting 75% of the time, not 50% if one chooses to accept your logic.
Flail mowers typically cut in a forward direction and can do a lousy job on wheeltracks in tall grass because the flails are travelling in the direction the grass is laying.

 

[dusty3030]

Not to start an argument again,

No, it is not BS as one blade is always following
the other as only half the cutting edge is used.
The basic physics and the rotary cutters design using the
right angle gearbox for a horizontal cut is the issue.

You only have half of the cutting edge exposed for
work because it is rotating away from and exiting the
front of the mower and the following edge is entering
the arc.

You insinuate half the width of the cutter is cutting at a time every time you post this and that is not true, each blade takes a full width bite every time you move forward.
Yes each of the two blades takes bites in succession but there are only milliseconds between the bites.

 

[RickB]

You insinuate half the width of the cutter is cutting at a time every time you post this and that is not true, each blade takes a full width bite every time you move forward.
Yes each of the two blades takes bites in succession but there are only milliseconds between the bites.

Using the same (flawed) logic, one could easily claim the typical flail mower blade cuts about 20-25% of the time throughout it's circle of travel.
Each type of machine has its plusses and minuses. Municipalities prefer flails over rotaries due to the lesser probability of foreign objects becoming dangerous projectiles along highways. Apart from municipal uses, rotaries probably outnumber flail mowers by 75 or 100 to one in this area.

 

[LD1]

Only half the blade is cutting....good thing there are 2 blades in there:laughing:


The real answer as I understand it:

Most cutters, when viewed from the top down, the blades are rotating CCW. This causes the grass that you cut to be thrown out the back of the cutter and to the right. (left if you are turned around in the seat looking at it). This expells the grass onto the side where you have ALREADY mowed IF you are going CCW.

IF you are going CW, you are throwing a nice row of chopped grass right where your next pass will be. If the grass is tall, you will see a nice row right at the edge where what you just mowed meets what you havent. On your next path, you are sucking a lot of this back up and chopping it again PLUS the fresh stuff you are trying to cut.

Kinda like cutting your lawn. If you keep blowing grass onto where you HAVENT mowed yet, the cut will get worse and worse with each pass vs blowing it AWAY.

 

[LD1]

Using the same (flawed) logic, one could easily claim the typical flail mower blade cuts about 20-25% of the time throughout it's circle of travel.
Each type of machine has its plusses and minuses. Municipalities prefer flails over rotaries due to the lesser probability of foreign objects becoming dangerous projectiles along highways. Apart from municipal uses, rotaries probably outnumber flail mowers by 75 or 100 to one in this area.

Safety is about the only good thing about flails. They take a LOT of HP and dont work nearly as fast in heavy stuff IMO.

Another plus I noticed though when I had mine is that a flail mower on the lawn seemed to be about the only thing that could cut the dandelions and leave a clean look and STILL maintain pretty good speed doing it. But I'll admit, I havent ever tried it with a RC. This is just in comparison to a finish mower.

Also, If you happen to run over a fence with a flail, it is a LOT less likely to stick a peice of wire in your tire like a RC. (I have hit fence with BOTH) BUT...I think the downtime to stick a plug and air up the tire from the RC was a LOT less than untangling the flail.