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Discussion Starter · #1 ·
While getting my 3300 ready for corn I noticed the concave has damaged bars. I'm guessing a rock went in it a long time ago and broke a couple welds and bent one of the cross bars the wires go through. Over time about 3 more welds have broken. I pulled it out so I could weld them back before something breaks loose and demolishes the combine. Actually there is only one of cross bars bent and about 4 welds that need to be fixed. I've got 5 or 6 wires that have broken and need replacing. I don't tend enough acres to justify $1000 for a new concave. Can I replace the wires with regular CRS, buy them from Deere, or what? How do I tell if the concave is worn out? I know its worn but what would dictate getting a new one or a good one from a salvage yard? I know very little of the history on this machine, I've only ran it over about 50 acres in the last 3 years. I've got to cover another 30 with it this year. I may replace the cylinder bars as they are worn into the bolts and the ribs are only a little over 1/4". As of now there is no damage on the cylinder bars. If I didn't need a set of tires on my dump truck, I'd just spring for a new concave, but common sense must prevail here. Any advice is appreciated.
 

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Discussion Starter · #2 ·
I checked the concave a little more closely. The first 3 or 4 bars show wear if you place a straight edge on them. The outer edges are lower than the center, is this a normal wear pattern?. Would it be acceptable to grind the center down until everything is level? The damaged bar and welds are all on the tail end of the concave--the end with the pivot bolts.
 

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If it was me I would get it to St John's welding and have them refurbish it, but I live closer to them than you. They have all the equipment to build them back and repair any broken welds, and when they are done with it is better than new.
 

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When a concave wears the center is lower than the outside edges. If the outside are lower then i would check to see if is bent. Sometimes they will bend. If your able to weld just patch it up and throw it in. Cold roll steel will be fine. Some of the manufactures use steel with a higher carbon content to increase the wear. The back side of the concave is pretty forgiving because there is more gap between the cylinder and the concave.
 

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Discussion Starter · #5 ·
Sending it to be professionally rebuilt would be great other than it would cost too much by the time I include shipping as opposed to what I can buy one for. I'll just go ahead and weld the breaks on this one and replace the broken wires.

I re-checked and the first 3-4 cross bars are high in the middle. Maybe it warped over time? One of them has a place it is bent down like a rock or something pushed it down. Would it hurt anything if I were to dress the high spots down a little closer with a hand grinder and straight edge? I'm thinking the high spots are what is causing me to have trouble cracking grain--especially milo (I've tried all combinations of concave spacing, rpms, seive openings, checking tailings--it was a big headache last year). The 2 pins and bolts came out fairly easy so its not like anything is severely bent/warped and it was under stress in the machine.
 

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It sounds like you're determined to McGyver this one back regardless of what we tell you so have at it. The shop that rebuilt one for me welded new bars to the old ones and milled them all flat again. Obviously you don't have the equipment to do that, but if the bars are badly bent and you can't grind enough to level them, you might try welding in some new metal, but keep in mind that you don't want to lose the clearance of the arc that the cylinder travels in from bar to bar either. If grinding is the preferred option, spend some time to try to get the leading edge of the bars square again as well. When done you'll have to be very careful about levelling and clearancing the concave to make sure nothing hits. Basically you will end up with a concave approx. 1/4" thinner that you will need to run slightly closer to the cylinder.
 

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Discussion Starter · #7 ·
Called St Johns this afternoon and was very impressed with the gentleman I spoke with. He told me a few things to check to determine how badly mine is worn. After looking at it tonight there are more bent bars than I first realized. Most of them are not really worn low in the center but the first couple are bent up high in the center. In a nutshell, too many rocks have been through it and did quite a bit of damage. The cylinder bars are much better off than the concave. I thought his pricing was reasonable, the freight is the worst part. I'm going to talk to him again and let him know exactly where my breaks are to see if mine is a useable core, he has a rebuilt one ready to ship. Worst case I'll weld the breaks in mine, replace the 5 damaged wires and get my corn shelled. Then I'll worry about replacing it---be nice to have some cash freed up as well.
 
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