Rotary Cutter Rotary cutters vs. RFMs

rtimgray · Aug 25, 2003

I suspect that he is referring to the check chains that suspend from the top link (or the hole below it) on the tractor that keep the lower link arms from dipping too low.

There was a conversation a little while ago about using a chain instead of a top link on a bush hog (as I often do) and someone asked if anyone had actually known of a rotary cutter flipping up and crushing the operator, and no one had. I think it is theoretically possible, but it's gonna have to get a lot of force to flip it up almost 90 degrees, plus it will have to snap/crush/bend the PTO shaft too. I do agree it is potentially dangerous to use a chain, but not very much so (probably more likely to get injured in a car wreck driving home to drive the tractor than getting hurt driving the tractor with chain top link).

yellowsocks93 · Aug 25, 2003

Hi guys, everyone always says you can't cut tall grass with a RFM but with my JD 272 RFM I have cut 10'' tall, thick hay/grass in our hay field without the tractor or mower bogging down. I have not tried taller stuff yet but I know it could easily handle it. I can cut taller grass with the 990 and 272 RFM than with the 4300 and 60'' 7 iron MMM. The 272 is deaper decked and I think this helps with the dispersal of the clippings.

Nick
990 4x4 turf, 272 RFM, 430 loader, 25A flail

shady1701 · Aug 26, 2003

My papaw said he seen a couple of state contractors they had heard of it they indicated alot of times the u-joint will bind up and break allowing the pto to continue on i think they were running 1000 rpm with a HD cutter?.. also this was on some major hp tractors i think but that's what he said if it could happen to big it's possible to happen....

F350Lawman · Aug 26, 2003

This has ben my experience:

1. Large, relatively flat and not too bumpy a land and the rotary cutter cuts well. lmost as good as my lawn tractor.

2. Tight turns, hills and bumby areas will cause the rotary cutter to bounce and cut into the turf due to the lack of wheels on the corners.

My rotary cutter goes vey well through long grass and doesn't bog. I think the long grass helps stop it from scalping when it does bounce.

rtimgray · Aug 26, 2003

I haven't seen too many state mowing contractors using 3 pt hitch bushhogs - as you said, most used higher powered tractors and tow type rotary cutters - I guess they can flip up too, but again, that's not too likely. The state mowing crews in our area (i.e. state employees, not contractors) use 3 pt hitch rotary cutters, and all of them that I have seen recently use a chain for the top link. Of course, they have a very heavy ROPS with a steel bar grill (not expanded metal) behind the operator, so it's doubtfult that even if it did manage to flip forward, it still wouldn't hit the operator.

But I'll agree if it's possible to happen, sooner or later it will.

djradz · Aug 26, 2003

My reference to check chains is not a chain for the top link, but in order to use check chains, you do need to have some type of flexible top link, such as a toggle connection, moving top link bracing, or chain between the connection point and someplace further back on the deck.

With regards to a chain for the top 3-pt link (again, not what I was originally talking about), I wish everyone would get a little more realistic. Trailer-type implements, including rotary cutters and RFMs have been used forever and still are commonly sold, without incident. These only have one connection and not only could fly up but could flip around sideways. Has anyone ever heard of this happening? Let's get real and quit raising unfounded fear. Just my $0.02.

shady1701 · Aug 26, 2003

there's a website i seen also who had how this could happen i believe it was on an antique or some other website they were talking about the bush hog coming over is possible depending on tractor make and bush hog.. granted it's not very likely however it has happen before and it's like riding a loaded gun for little results..

slowrev · Aug 26, 2003

Yep never heard of a hog flying up and getting someone. However on my old 5 ft Hog I have replaced the straps from the toplink hookup point on the top of the Hog hookup back to the deck of the Hog with chain. Works great, toplink still there and the hog is allowed to follow the contours to minimize scalping and such. Less strain on the hitch on the Hog too.

rtimgray · Aug 26, 2003

granted it's not very likely however it has happen before and it's like riding a loaded gun for little results..

I still have yet to see any defined proof that this has actually happened to anybody - not to say it can't, but it seems like we keep getting "I knew a guy who heard from a guy that it happened to a guy he knew...etc".

As for the little results - it's a lot more forgiving when you are going down a hill to a level area or, worse yet, back up another hill (i.e. mowing a gulley). If you have a rigid top link and a rigid bushhog frame, you can actually lift your rear wheels off the ground, then you will free wheel (unless 4wd engaged). More likely, you will bend/break your top link/bushhog frame, etc. I think that the reward far, far exceeds the minimal risk involved. I honestly cannot imagine hitting something with such force with the bushhog that it will flip up 90 degrees and crush me...If I hit it that hard, it might bend/break the top link anyway...