Mower comparison: sickle bar, flail and rotary

[Maine Hills]

We have a BCS 749 with a 59" BCS duplex sickle bar mower, a 32" Berta flail mower and a 32" BCS/Del Morino brush mower which are used to mow a former pasture and a wild blueberry field. Most of the fields are mowed once a year. The wild blueberry fields are mowed every other year. I spread the mowing over the second half of the summer. During hot weather I mow in the late afternoon or evening when the sun is low and the air has cooled. 3 mph is possible for mowing short grass on smooth level ground but my speed is usually considerably slower. Locking the differential is helps keep the mower headed straight when mowing across steep hills.

The BCS sickle bar mower is used as primary mower for parts of our fields which are too steep for me to mow with a four wheel tractor and rotary cutter. Most of the fields are mowed once a year and the grass an thin wood plants can be six feet tall. The skids are set for about four inch tall cut. The fields have lots of large rocks and the sickle bar rides over the rocks with no problems. The cut grass can take a couple of months to decay after cutting but that has not caused any problems. Occasionally the sickle bar mower will push tall cut grass along for a while and then leave of large clump. Cutting large areas with second year Burdock or other thorny plants which tend to stick together was not satisfactory with the sickle bar mower. It will cut the stems but the plants will remain standing and just be pushed along until no more progress is possible. Individual plants are not a problem. The sickle bar mower initially tended to ride up when going up steep inclines or over large lumps and bumps. This was eliminated by adding a PTO extension and a mower. I mow with the engine at half to two-thirds throttle. Second gear is used for most areas but first gear is used on steep slopes or in tight areas.

The Berta flail mower has several uses. The wild blueberry field need to be cut close very close to the ground every other year and flail mowers are the standard mower for that use. The roller is set for about a half inch cut. The flail mower is also used to mow around the edges of the lawn where it provides a satisfactory cut, though perhaps not quite suitable for a garden club tour. The flail mower is fantastic at mulching, and is used to mow and mulch flower beds in the fall. We also use it to mulch cuttings from bushes, particularly thorny bushes - lay the cuttings on the ground and mower over them with the flail mower. Another use is cutting the bottom of a wide drainage ditch. The flail makes noise when a rock is encountered, and very occasionally a small rock will be ejected out the front of the mower. The flail mower sometimes bogs down and then clogs on grass over three feet tall so it is not satisfactory as the primary mower for tall grass. Second year Burdock stems will wind around the drum and stall the mower. Full throttle is usually used and most mowing with the flail mower is done with the tractor in first gear. We purchased the accessory front wheels with the mower but took them off after the first season and haven't reinstalled them.

The BCS/Del Morino rotary cutter is used for thick brush and anything which will clog the flail mower and which we don't want to mow with the sickle bar mower. It will handle clumps of second year burdock and pretty much anything it can push over. Thick stems will sometimes bend over and the mower will ride over them. In those instances I have found backing over the stems with the mower down and cutting, and then going forward a second time will usually cut the stems into sufficiently small pieces. However the rotary cutter does not do close to the amount of mulching which the flail mower does. Full throttle is usually used and most mowing with the flail mower is done with the tractor in first gear. We purchased the rotary cutter after finding there were situations, particularly mowing second year Burdock, where neither the sickle bar mower nor the flail mower was not satisfactory. It's become the first choice for clearing brush in areas inaccessible to our four wheel tractor and brush cutter.

 

[Freep]

Great post - very helpful. I am looking to purchase a BCS 853 and a mower. I am leaning toward a flail mower, but am not yet fully decided. I had not considered a sickle mower, however I have access to BCS 720, which can run a reasonable size sickle bar mower (other mowers not really an option). So I am at least considered the possibility now.

How tall does your grass need to be before the sickle bar mower can do a decent job cutting it? I have heard that sickle bars perform poorly with short-ish grass.

 

[Maine Hills]

Our sickle bar mower height is set at about four inches. I know it doesn't do well on grass that is only a few inches taller than the mower, but have not experimented to determine the minimum grass height necessary for a satisfactory cut. My guess is if the sickle bar mower was closer to the ground it would do better on shorter grass because the grass would bend less.

In many respects our flail mower is the best all around mower as long as the grass is not over three feet in height.

 

[Freep]

I'm not positive, but I think I could manage to limit my neglect to 30 inches. I'll bet that sickle mower is great for people with grass-eating livestock.

 

[Egon]

Sickle bar's must be kept sharp & properly set up. No slop on the ledger plates. Some grasses cut much harder than others.

The number of cutting actions per minute must be correlated to ground speed.

 

[leonz]

Helllo Freep, Egon is correct in what he has told you.

About your beautiful flail mower, you should reinstall your front caster wheels and use them. The other thing is you should be taking half cuts with the flail mower if you leave the brush that tall.

If you invest in a wet well grinder for your flail mower knives from micromark $99.00-the last time I checked and the angle setter from woodcraft $25+- you will be able to to sharpen the flail mower knives and they will cut very well all the time every time. The cutting edge angle should be about 37 degrees so you can set the grinders tool bed at that angle. If you can sharpen the knife edges on the sickle knives great the wet well grinder will work well for that too and not lose the knife temper as it cool grinds all metals on a low speed wheel.

 

[Maine Hills]

The sickle bar cutters are sharp. The BCS duplex sickle bar mowers has springs which keep the bars together. I have not had any problems with the blades not sharp enough nor with not enough pressure on the blades.

So far I've been satisfied with the flail mower without the caster wheels. I'll probably reinstall them this summer and experiment.

Taking half or less width cuts with the flail mower in very tall grass does not solve the problem of the grass wrapping around the drum which I've had occasionally.

 

[CodeMonkey]

Tried a BCS 30" sickle bar this morning thinking it would be faster than the flail.

It is if I put the tractor in second gear, but I have a hard time keeping up with it - especially on uneven ground. Also, on rough terrain, because of the light weight of the mower, the bar bounces up and I miss areas.

The end result is that I went back to the flail mower - I can keep up with it in first gear and it mulches what I am cutting.

 

[jcraftenworth]

There's something very satisfying about running a rototiller and a flail mower and seeing the soil or plant matter pulverized into smooth tiny pieces!!!

 

[Maine Hills]

Bump since it is prime equipment buying time.

 

[Freep]

Update bump, too: I bought an 852 and a 34" flail mower. Both have worked well. I have not typically mowed in first gear, except for maneuverability's sake. For grass up to a foot tall or so I am usually in third gear. The only time I downshift is when mowing actual 'brush'. I use the mower to mow about 3 acres of pasture a few times per year when it starts to get out of hand, and have this spring been making some trails in the woods.

 

[Maine Hills]

Where do you set the throttle for flail mowing? I always have it at maximum engine speed, and that is too fast for me walking in third gear, so I use second gear or first gear depending on the terrain. The large diameter 6.50 x 12 tires cause the ground speed being faster than it would be with smaller tires, but I really like the tires when working on rough ground.

 

[Freep]

Same here - full throttle. In third gear it is quite quick. I do touch it back just a wee bit sometimes if I'm having a hard time keeping up. It's fine at 3/4 throttle with the BCS 852/3 at least. I also have an Earthtools mowing sulky, which I recommend, but which can get rather bumpy.

 

[Maine Hills]

Any where the ground would be smooth and flat enough to use a sulky I mow with rotary cutter (brush hog) on a Kubota 4 wheel tractor.

 

[Maine Hills]

Updates fromm my previous posts in this thread: The flail mower is our favourite mower until we hit it's limitations. I don't try to cut thick grass much over 2 feet / 600 mm high with it and also avoid tall, fiborous plants such as mature burdock. The rotary brush cutter is great for conditions which are too much for the flail mower. The sickle bar mower is only used for open fields and in those conditions can be fastest mower to use and the least tiring. While it will cut small diameter woody plants it is not great on plants with thorns since it only cuts the plants near the base. The cut plants can tangle with themselves and the tractor, and will scratch my legs. But with tall grass and similar it is great.

In addition to mowing the flail mower is used as a mulcher. Spread cuttings from bushes and small trees up to 3/4 inch / 19 mm diameter on the ground and run over with the flail mower set to a low height. A nice mulch is left.

While the rotary brush mower cuts plants into multiple pieces the result is not nearly as fine as when cut by the flail mower. Also cutting height of the US version is set to 4 inches / 100 mm so it does not cut up anything laying on the ground which is lower. The flail mower is set for a cutting height under 1 inch / 25 mm so it picks and mulches most sticks etc on the ground.

Power: We have a 749 with a 11.7 HP Honda GX390 engine. There has always been enough power for the 59" sickle bar mower with half throttle, including with 6 foot / 1.8 m tall grass. I usually use full throttle with the 32 inch rotary brush mower and almost always there is sufficient power. The 32" flail mower is also used with full throttle and a few times it has bogged or even stalled, usually when trying to mower tall fiborous plants such as mature burdock which can wind around the mower drum. Also in heavy, high grass the mower can be limited by how quickly it can discharge the cuttings even with the baffle removed.

The caster wheels were reinstalled on the flail mower with the updated mounting bracket. Berta flail mower caster wheels The flail wheels are great for transport and for mowing as long as the not mowing across as steep hill. When mowing across a steep hill with the caster wheels lowered the unit wants to turn downhill. Engaging the diff lock helps but I usually also raise the caster wheels. With the Berta flail mower raising the caster wheels only takes a minute or so.

 

[Jens767]

Hi Maine Hills

I have read your posts in this thread a number of times, and I think they are by far the best ones in the 2-wheel tractor forum, when it comes to comparing different mower types

I have no experience with a brush mower, so I can’t comment on that one. Concerning the sickle bar mower and the flail mower, I fully agree with all your comments - they fit perfectly with my experience as well, and they should be a great help to anyone considering to purchase some type of mower.

There is one subject though, that I would like to add to your comments, which I think is important to consider before choosing a mower, and that is what you want to do with the clippings. This question might seem obvious to the experienced user, but might be overlooked by someone with little or no mowing experience, and might therefore lead to the purchase of the wrong type of mower

In principle, there are two options when mowing: either you leave the clippings on the job to decompose, or you remove them.

If you want to leave the clippings to decompose, mowers like the flail and probably the brush mower are the obvious choice. If you want to collect the clippings, mowers like the sickle bar, the drum mower - and of course, the lawn mower are the better choice, depending on the job in question.

Sickle bar and drum/disc mowers all cut the material at the base, allowing it to be easily collected either by hand or by machine. In principle, it is of course possible to leave the material to rot, but that is usually not desirable. The brush mower - and especially the flail mower - both chop the cut material into smaller pieces, thereby allowing it to decompose better. On the other hand, it is difficult/impossible to gather the material for removal.


Best regards

Jens