Repairing sickle knife bars - Page 2 - The Combine Forum
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post #11 of 20 (permalink) Old 07-31-2019, 05:01 PM
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splice kits work well, around $20-25 for the ones I just purchased to put together a new sickle. I have welded a few. I usually weld a few sections together around the break and use them to help hold it together. Do similar to everyone else menitoned above. I like the idea of chain links to strengthen. My 2152 uses links between sections at the ends to strengthen. Similar to the chain link idea? Almost never as strong as before the break (when I weld it) so I do what I can to keep it together.

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post #12 of 20 (permalink) Old 08-01-2019, 12:50 AM Thread Starter
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Thanks everyone for your feedback. I'm really hoping to avoid using any splices on this, that's why I want to try to weld them. I'm planning in replacing the knife sections anyway so after I weld the break together I'll probably flip the bar around so where it broke will be on the right hand side of the header. Should be a lot less force put on it there.

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post #13 of 20 (permalink) Old 08-01-2019, 07:29 AM
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Thanks everyone for your feedback. I'm really hoping to avoid using any splices on this, that's why I want to try to weld them. I'm planning in replacing the knife sections anyway so after I weld the break together I'll probably flip the bar around so where it broke will be on the right hand side of the header. Should be a lot less force put on it there.

I was hoping someone else would post this described method because it takes a fair bit of writing to explain it.

With this method you do need another piece of knife bar stock because you will need to also do the same weld procedure on the outer end of the knife to keep the knife the same length.

Rather than weld a straight break through a rivet hole, sacrifice some knife length and cut it on a long diagonal between two rivet holes directly under a section. This generally means a hacksaw cut just under two inches long. Once one piece has been cut off next to the break, use a knife section and some bolts to align the other parts properly to scribe the matching angle to be cut on the other knife segment that is is to be welded. Chamfer the pieces to less than half depth that are to be welded and then bolt it together straight using a section to bridge the weld joint. Once it’s tacked or welded on one side get the section out of the way to finish up.

I like to use a 1/8” 6011 on ac current set at about 90 amps using a start stop method as required, but that’s just me. You can hammer the weld a bit while it’s hot on a railroad iron if you are working on the floor, but don’t over do it. Tidy things up a bit with an angle grinder and bolt the section over the diagonally welded joint.

Now cut the outside end off and do the same weld procedure to get the proper knife length back using your extra knife stock.

I’ve repaired dozens of knives this way over the years, it will not break at or near the weld and the time spent is well worth the long term satisfaction.
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Last edited by Haystack; 08-01-2019 at 08:17 AM.
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post #14 of 20 (permalink) Old 08-01-2019, 09:15 AM
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I've used Haystacks method for years... mainly to make a longer bar out of two shorter ones usually picked up at auctions. I use a stainless rod for the weld.
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post #15 of 20 (permalink) Old 08-02-2019, 01:03 AM Thread Starter
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Thanks for the method you described @Haystack. That's definitely how I'm going to do it. I just need to scrounge up some extra cutter bar stock.
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post #16 of 20 (permalink) Old 08-02-2019, 01:27 AM
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I just slide the broken side too the sickle head than take the small piece off to the other side of the header and weld together there, not too hard to do and if you are short a welder the sickle sections can often pull ya through because it's a short piece.
Does that make sence?
Saves pulling the sickle completely out when it's still go time.

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post #17 of 20 (permalink) Old 08-06-2019, 11:21 AM
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The key for me is to use an old donor sickle for the repair re-cut the broken sickle to be repaired so the break falls in the center of a sickle section then use a donor sickle to finish out the sickle your section acts as an extra brace. You may have to re drill the end section hole if it has a narrow section. It is an extra step but it is really worth it. I Use 7018 or another rod called super missile weld. BUT SMW it does not grind very well it is hard. or a wire welder will work of course.
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post #18 of 20 (permalink) Old 08-06-2019, 12:24 PM
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All I've ever done is TIG weld them with stainless then weld the section on top of the break to the ones next to it. Never have had one fail near the weld and through a section.
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post #19 of 20 (permalink) Old 08-06-2019, 07:12 PM
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Originally Posted by Haystack View Post
I was hoping someone else would post this described method because it takes a fair bit of writing to explain it.

With this method you do need another piece of knife bar stock because you will need to also do the same weld procedure on the outer end of the knife to keep the knife the same length.

Rather than weld a straight break through a rivet hole, sacrifice some knife length and cut it on a long diagonal between two rivet holes directly under a section. This generally means a hacksaw cut just under two inches long. Once one piece has been cut off next to the break, use a knife section and some bolts to align the other parts properly to scribe the matching angle to be cut on the other knife segment that is is to be welded. Chamfer the pieces to less than half depth that are to be welded and then bolt it together straight using a section to bridge the weld joint. Once itís tacked or welded on one side get the section out of the way to finish up.

I like to use a 1/8Ē 6011 on ac current set at about 90 amps using a start stop method as required, but thatís just me. You can hammer the weld a bit while itís hot on a railroad iron if you are working on the floor, but donít over do it. Tidy things up a bit with an angle grinder and bolt the section over the diagonally welded joint.

Now cut the outside end off and do the same weld procedure to get the proper knife length back using your extra knife stock.

Iíve repaired dozens of knives this way over the years, it will not break at or near the weld and the time spent is well worth the long term satisfaction.
.
I like your method of cutting the long diagonal repair and your description of the prep and everything. I am somewhat surprised that 6011 gives you the ductility for the flexing and pounding of a knife. Also a couple of other guys saying they weld these with stainless is surprising. I have recently had some very disappointing experience with SS bolts and being very soft and weak when it comes to thread strength and trying to torque them to some normal spec. Not saying you are wrong and if it works for you then you are right! I know 6011 is so nice to work with. Fast freeze and easy to control the puddle and clean out the slag and all those benefits. It just tends to be more brittle. Which is why I would have thought 7018 would be the only rod that could take the flex and pounding. I learn something most days if I pay attention!
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post #20 of 20 (permalink) Old 08-06-2019, 10:03 PM
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Yeah metallurgy is sometimes surprising. My wife has a titanium spine, but it still works better than before!

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