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 | Clemson
Join Date: Jul 2003 Posts: 13 South Carolina 
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2002-03-21 36575
How far can I extend a Category I top link before I need to worry about getting an extra long one? Mine has a 16" body, and I have it let out to 27" between centers of the pins that I am connecting (tractor and rotary cutter). I see a lot of threads. Am I in danger of breaking a link?
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 | DRankin
Join Date: Jan 2000 Posts: 5116 Northern Nevada 
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2002-03-21 36578
Here is my educated guess, but I know we have some engineer types reading these posts that can put their two cents in the pot. If you observe the length of the female threads on each end of your top link and make sure that your have at least that amount of male threads occupying the space, then you are in no more danger of stripping threads then if the link was shorter. Boy that is as clear as mud, huh? I suppose that the more the top link is extended the greater the bending forces might be, but, when you consider that the forces run in a pretty straight line from the implement to the tractor there seems little chance to bend it that way. I bent my top link on my 4100, but I did it by getting something caught between the link and the frame of the tractor while raising an implement. You should pull the link completely apart to see how much extra thread you have. A mower seems like it would have much less inherent stress on a top link than using a ground engaging gizmo like a plow or a box blade. ....
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 | Peters
Join Date: Feb 2002 Posts: 3034 Northern AL
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2002-03-21 36581
Strength wise on a linear force you need a bout 6 or 7 threads. For bending force it wouuld be better like Mark said to have the thread at least near the area where the tube diameter expands. The smaller diameter (threaded tube) will be weaker than the other diameter tube unless the rod is it.
Many people use a flexible top link on a rotary cutter like a chain. ....
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 | Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2002-03-21 36582
Just to add a little tip to the comment Peters made about using chain for an upper link. This is a very common practice in this neck of the woods indeed since the relatively long trailing length of a rotary cutter and the uneven terrain on which they often operated makes for a bad combination. We discovered years ago that a short section of strong rubber strap (such as a piece of tire sidewall) bolted through the chain in 2 spots so as to leave 2 or 3 links of slack will act like a shock absorber and make life a whole lot more pleasant while cutting and moving the tractor around generally. Best of luck. ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2002-03-22 36602
I’ve never been real clear on top-links and cutters. I guess the idea of a flexible top link is that it allows a cutter with only a tail wheel to follow the ground contour better than with a fixed link. Sure would help get a tractor off a trailer too. Tractors with backhoes have the same problem.
I seem to recall hearing of both flexible links and chains. I don't know if they're the same things or not. I've heard of masts used with chain links. I don't know if a mast would be required. I do think that a cutter with a fixed top-link would produce as much compression as a ground-engaging implement. The worst case would be if the tractor rear wheels go into a dip ahead to the tail wheel. The rear of the cutter would move up and there could be a lot of leverage given the distance of the tail wheel from the 3ph pins. However, I think the amount of compression would be limited because the 3ph lift arms could float upward.
Maybe I'll get a cutter someday and then have to figure these things out.
....
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| JimTN
Join Date: Posts: 1
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2002-03-22 36632
Tom G: For what it's worth. My flail mower came with "floating top link". My best description is an inverted "U" shape of flat steel, pivoted at the mower top link. There are two sets of holes near the open end of the "U" where the tractor top link is connected to the selected set of holes. My mower was delivered with the "U" shape angled about 45 degrees forward when the mower is down on level ground. As the rear tractor wheels go in a dip, the floating link swings toward the back. When the mower is lifted, the floating link swings straight forward then the top link pulls the mower off the ground.
Hope this helps.
Jim ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2002-03-23 36641
Thanks Jim. My impression is that standard top-links aren't that great for mowers and also that flexible and chain links were different and commonly used. I noticed a typo in my first post. I should have said that I don't think mowers produce as much top-link compression rather than I think they do. Some year I might be able to proof read on the screen. ....
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