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Discussion Starter · #1 ·
In the past, with our 23 and 2588, the internal straw chopper knives would wear, but at a slow rate and maintain a sharp edge on one side. The 740, after about 500 hours, had very rounded knives and were flipped. At about 800, I replaced them. I did this over the winter, learning that residue management is important, especially when no-tilling and working with a 40' header. The knives reminded me of the typical 9500 chopper knife, very rounded and dull. After pricing Claas knives, and being unable to find a sharper, longer lasting knife IIRC, I looked for alternatives.

Redekop has a kit out for the S series deere machines, as they no longer supply a chopper for them from the factory. After doing some measuring, I bought enough for the 740, using the bolt, bushing and knife from the kit. The bolts, and bushings are 14mm instead of 12mm IIRC. The knives are the same length, but the eyelet is closer to its end, giving it a larger circumference. The knives cleared everything except a rear guard that I relocated to the rear by maybe 10 mm. The knives are supposed to be long life, with a carbide edge IIRC.

I also ordered 6 "wide wing blades" for making more air to blow the residue out on the ends. These were a very tight fit. I re-centered the "rotor" to be exactly in the middle, as one side was slightly closer than the other. The wide wing blade has an offset in it. It is not designed for this rotor, but works. It is supposed to be bolted to the inside of the left and right rotor "ring" but that wouldn't work without other modifications. It does fit on the outside, like the factory wing blades, but it will not rotate like the knives or factory wingblade, due to this offset hitting the ring.

I harvested a few hundred acres of lodged wheat after installing. I was very happy with how it turned out. Spread was good unless the side wind was against me. HP seemed minimal and the cut was great. I will post some pics if I have time or someone is interested.
 

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I have been wondering if there was any "upgrades" for the chopper knives. I will be replacing mine before we start harvest. I was looking in my parts book, and I noticed two different part numbers for the knives. I looked at both sets of knives at our dealer, and I saw that one of the knives looks to have a thicker ring at the center where it bolts on. Otherwise, the knives didn't look that different for each other. Sorry to highjack this a little, but I was wondering if one "stock" knife is better than the other.
 

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Discussion Starter · #4 ·
Yes, I believe it threw farther. Soybeans will be a better test imo.

I can't see how a thicker knife ring hole would help much. Maybe it prevents them from breaking off due to foreign objects. Had that happen one time and you know it immediately.

I do like the Claas knife that it has a larger hole...more surface area to wear as the knives rotate.
 

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Thanks for the update Seedcleaner. I'm glad you are making progress on this problem. Just to update you from this end, I just received a kit from Redekop for my 590 with new carbide knives (part # 490-050) , bushings and bolts to fit. The knives are 6" long from hole center to tip so are just 1/8" longer than original non carbide and 1/4" shorter than the old HA650C. So that was a simple bolt in solution, however when I look at the carbide coating , it is on both sides of the blade and not even sharp to start with, so those are not going to self sharpen as they wear and can not be ground sharp like the old HA650C that had carbide only on one side of the blade. That style allowed the softer base metal to wear away somewhat, leaving a sharp , jagged carbide cutting edge that could also be sharpened once in a while by taking all the knives out, grinding with an angle grinder, weighing them into similar groups for balance, and then reinstalling for another life with little cost and a sharp edge. However now in hindsight , I think if the new bushings would take the HA650C knife, that may be the best combination. Is 1/8" of clearance at the end of the knife enough? The longer the knife, the greater the mass and tip speed = better chopping in my mind??
 

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Discussion Starter · #7 ·
Transaxial, for me, when finished, clearance was very close with the larger 2" wind blades as well as the knives. As long as it cleared by hand, I didn't seem to have an issue. I ran it first of course before going to the field.

I never tried too hard to get a deere blade to work. It seems like too many different things to deal with, so I just found a solution from Redekop.

In fact, I removed the chopper belt and put my screw gun on the bolt that holds the drive pulley on. That can get the chopper spinning pretty good without the engine noise and other things distracting you. It is a good way to check the balance also. Be careful when doing so. My Milwaukee 18 volt screw gun will "cancel" if a big load is put on, locking it. When that happens, your wrist and tool takes a beating!
 
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