Rotary Cutter Does Direction of Travel Matter?

[leonz]

Edited:


A rotary cutter has only half its cutting edge exposed for mowing at at any time simply because of the design of the mower and its horizontal cut.

A flailmower uses its entire rotor width and knive stations for mowing.

A 4 foot finish cut flail mower with 64 mounting stations will have 16 pairs of side slicers-32 side slicers per row where each slide slicer may have a minimum of 1.5 inches of cutting edge per knive or 3.0 inches per station with sixteen stations and the thirty two side slicers will have a total of 48 inches of cuttting edge PER row providing a total of 192 inches of cutting edge per rotation of the flail mower rotor at speed wherein each of the 132 side slicers removes 1/4 inch of brush height per rotation. MR. Mott knew exactly what he was doing with the Mott Interstater.

With flailmowers versus a rotary cutter or rear mounted rotary mower its always a case of brute force of a rotary cutters pair of blades versus the mechanical advantage of a flailmowers rotor using the X plane(vertical) versus the Y (hoizontal plane) in mowing (cartesian coordinates)in comparing a rotary cutter versus a verticut mower(finish flail mower) or even the smallest flail shredder for crop shredding or topping sugar beets.


Edit:
A rotary cutter does not cut as finely as a flailmower so it leaves much more in cuttings in its wake and it cannot recut the clippings unless they are tinder dry and in effect shatter them.
If we had more front mounted integral implements using the Power Take off from the flywheel as they do in Europe we would have much less trouble mowing and leaving the area as well mowed as one would like to leave it
as the entire area directly in front of the prime mover/implement carrier would be mowed without unmowed brush from wheel tracks.



Food for thought on a Sunday.

 

[LD1]

You win. Feel better?

Not really. Just trying to have a discussion, not trying to "win" anything.

The OP asked about HIS cutter and HIS tractor. ONLY thing being different is the direction of mowing. You brought up different cutters performing differently, which is true, but irrelivant to the OP. Now, if he asked "why does my bushhog brand cutter do better than my woods" or something like that...

A rotary cutter has only hlaf its cutting edge exposed for mowing at at any time simply because of the design of the mower and its horizontal cut.

A flailmower uses its entire rotor width and knive stations for mowing.

A 4 foot finish cut flail mower with 64 mounting stations will have 16 pairs of side slicers-32 side slicers per row where each slide slicer may have a minimum of 1.5 inches of cutting edge per knive or 3.0 inches per station with sixteen stations and the thirty two side slicers will have a total of 48 inches of cuttting edge PER row providing a total of 192 inches of cutting edge per rotation of the flail mower rotor at speed wherein each of the 132 side slicers removes 1/4 inch of brush height per rotation. MR. Mott knew exactly what he was doing with the Mott Interstater.

With flailmowers its always a case of brute force versus mechanical advantage using the X plane versus the Y plane of Cartesian coordinates
comparing a rotary cutter versus a verticut mower or even the smallest flail shredder.



Food for thought on a Sunday.


compared to the 24 inches of one blade on a rotary cutter.

So why does a rotary cutter cut 24" grass faster with a better cut than a flail assuming same tractor and same width cutter?

 

[RickB]

Not really. Just trying to have a discussion, not trying to "win" anything.

The OP asked about HIS cutter and HIS tractor. ONLY thing being different is the direction of mowing. You brought up different cutters performing differently, which is true, but irrelivant to the OP. Now, if he asked "why does my bushhog brand cutter do better than my woods" or something like that...

Everything I posted is relevant to why the OP's setup does a better job in one direction than the other, with the exception of a short detour to leonz' flail fantasy world.

It's not all about throwing cut material into the uncut area although that can be an issue. You might want to occaisionally recognize the possibility that an opinion other than your own may have some merit. Good Day.

 

[the6shooter]

Hey guy's. Here is something that has not been discussed, mower not being square with the tractor. I.E. dog legging off to the side.
I learned this over time, and adjust for it. If the tractor and mower is off just slightly, you will also leave rooster tails, because the side of the cutter will lay a small strip of grass or weeds that will spring back up after you pass it.

I always mow with the blade side that is comming forward in the cut, and the rearward movement to the aready cut side.

Now that being said, some cutters are clock wise and others are counter clock wise.

Now you can, also have too much movement left to right and vis-versa,
Set your mower slightly off the ground, and stand to the rear for your cutter, and check to see if you can swing the tail in either direction and if you can move it a foot or more, take out the slack, this will also help with the rooster tails.
Any bit of drag, to the tail wheel will make the cutter dog leg off to one side or the other. and you can really tell when mowing across slight slopping spots of a field. because the tail whell will always want to run to the lower side. Once again, take the side to side slack out.

Hope this made sense.
david

 

[gwdixon]

Just to continue the discussion (but a bit off topic), my Landpride with two cutting blades rotate in opposite directions. One is CCW while the other is CW. Now carry on.

After that, let us discuss batwing mowers with three cutting blades. farmwithjunk where are you?

 

[bcp]

What's a manual?

Joe

Not automatic.



Bruce

 

[TerryR]

This discussion is making me wonder the way I set up my rotary mower. I have a 60" Bush Hog Squealer, which is not as wide as the rear tires on my JD 870. I have them set to maximum width because of the steep hills on our property.

So I set the mower to the left side, so its left side is about flush with the outside the left wheel. That way, after the first pass, only the left side tires are running in the uncut area.

With it set this way, the blades are moving forward on the left side, and don't tend to pick up the downed grass, which is also bent forward. But I do that because the blade is moving backwards on the right side, where it does tend to pick up the grass downed by the previous pass. My theory is that the grass has the time between one pass and the next to upright itself a bit.

I'm now wondering if I might do better if I reversed the setup so that the pickup action is applied to the freshly bent grass.

I sometimes get rooster tails, but generally not for several hours, or even a couple of days. How bad they are seems to depend on how sharp the blades are, and probably more so, on how recently it's rained. It seems worse when the grass is too dry, I suppose because the grass crushes stays down during my second pass, then comes back up later.

Terry

 

[bcp]

Why does my mower cut better in one direction?

Coriolis effect, adjusted for latitude and air density.



Bruce

 

[LD1]

It's not all about throwing cut material into the uncut area although that can be an issue. You might want to occaisionally recognize the possibility that an opinion other than your own may have some merit. Good Day.

What is your opinion then??? Because your earlier post was pretty confusing about picking up the wheel tracks and overlapping???

I guess the way I mow, I have TWO tire tracks either way I go CCW or CW, because I DONT overlap because it is not as efficent. So with NO overlap, and a 6' cutter on a 5' wide tractor, it dont matter the direction as far as the wheeltracks are concerned.

a short detour to leonz' flail fantasy world.

At least we agree on something :thumbsup:

 

[RickB]

What is your opinion then??? Because your earlier post was pretty confusing about picking up the wheel tracks and overlapping???

I guess the way I mow, I have TWO tire tracks either way I go CCW or CW, because I DONT overlap because it is not as efficent. So with NO overlap, and a 6' cutter on a 5' wide tractor, it dont matter the direction as far as the wheeltracks are concerned.



At least we agree on something :thumbsup:

There are always two wheel tracks. One or the other will be picked up immediately, blade rotation direction dependent. The other wheeltrack can be managed by the direction travelled and overlap. Overlap certainly is inefficient, but can increase cut quality dramatically in certain conditions.

 

[LD1]

Overlap certainly is inefficient, but can increase cut quality dramatically in certain conditions.

Agreed. If you have one wheel track that isnt cutting clean, mow in a direction that leaves THAT wheel track closest to your next pass so you can hit it with the least amount of overlap:thumbsup:

 

[Lineman North Florida]

I've always had good luck mowing back opposite of the way I just mowed, meaning my tractor tires mash down the grass in the tracks going one way and when I come back the opposite it seems to help stand that grass back up so I don't have many bahai stems sticking up. I have also learned that there are 2 different types of blades for a lot of rotary mowers, my Bush hog 720 Squealer came with flat rough cut blades and cut poorly in my opinion, I bought a set of curved lifting blades and it cut 100% better.

 

[gsganzer]

This is an old thread and I'm sure it gets beat to death again every other year, but I'll throw out a helpful tip to anyone new to mowing with a rotary mower. At least this is how I learned it.

Make a pass through the tall grass. Then stop and look at your deposited cuttings behind the cutter. If the cuttings are concentrated on the left side (of your direction of travel), you should proceed CW, if on the right side, you should proceed CCW.

In other words, the bulk of the deposited cuttings should be on the outside of your cut.

 

[zzvyb6]

Because of the rotational direction of the blades, 1 direction of tractor turning raises the effective blade speed, the other reduces the blade speed.
So: Make sure the pto rpm is correct (540) and slow down your tractor turn speed so you don't outrun the inboard blade. Same thing with an offset sickle bar mower. The cutter actually backs up if the turn center is not properly located. What's important is the mower turn center, not the tractor's.

 

[leonz]

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.

Flail mowers with double edge side slicer knives are able to slice brush and grass in forward and reverse if desired.

 

[Fallon]

Flail mowers with double edge side slicer knives are able to slice brush and grass in forward and reverse if desired.

Flails don't cut well in reverse at all. I assume because of the roller pushing grass down, but don't know for sure. My Peruzzo has hammers, but my old Ford 917 has side slicers. Both only cut half the material in reverse. If I drive forward over what I just cut backwards it cuts fine.

 

[oosik]

My 2 1/2 acres of "lawn" is really mowed field grass. After 40+ years of mowing - it looks pretty good. AND it is the fire break for my house and out buildings.

Anyhow - I've learned to mow in a CCW direction. All the cut grass is blown away from the uncut. Makes sense and cutting is much easier and cleaner.

 

[Fallon]

Mowed part of the yard today. Took the opportunity to grab a video mowing in reverse & the resulting half the material that gets missed. Not the greatest video, but should give the idea

 

[dadohead]

Spent 30 yrs at JD putting many tractors and mowers into production. Mowers look easy but are very tough to design. Finish mowers, rotary cutters, and flails all 'impact cut': you hit the plant fast enough to cut it before it moves (usually >12000 fpm). Its easiest to do that when the plant is standing straight up.... but that often doesnt happen. The tractor tires mash the grass forward in 2 strips; the mower housing also bends the grass forward just before cutting.

We used to call the region of the mower where the blades are cutting in the reverse direction the "back sweep" portion of the mower. Where the blades are traveling forward is "forward sweep". Back sweeping grass that is bent forward results in a very clean cut. On my CCW cutter, the LH side is the strong cutting side. The RH section is where the forward sweep is trying to lift and cut the tire track.... usually a MUCH weaker cut.

So, knowing the LH side of my cutter is the strongest, I mow CCW around the field letting the LH side back sweep the grass. I keep the RH side in the previously cut path. Direction definitely matters! Good discussions above.... hope this helps!

 

[buckeyefarmer]

I observed this week that ccw was better than cw.