Go Bottomdealing with bent draft links
 | Eric Edwards
Join Date: Posts: 1 
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2001-11-28 33508
I have a couple of bent draft links from the 3PH of a JD 1070 to fix. One is probably out 5" or so and the other one an inch or better. The bend occurs mostly at the point where the sway chain attaches to the link. JD has put hole though the link at this point for attachment. I also have a broken sway chain which led to bent forks on the lift links and a 30 degree bend in the threaded rod portion of the adjustable lift link. I consulted my JD dealer and he said that if I cold bent them back without then anealing and then heat treating them that they could snap. Is he pulling my leg? He scared me into ordering a replacement for the worse one. Is there a good method for dealing with this. If I cold bend or bang (read 10lb sledge) them back does any one know what kind of strength I'd be losing if any? Anyone out there an expert at this metalurgy stuff. Oh; and if you have two friends who want to drag their old truck out of the woods with your machine and logging winch, in your abscence, just say NO!
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley 
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2001-11-29 33511
The last sentence is a killer. I was wondering how they got bent. I think what your dealer said is right. Some of the risk would depend on the type of steel the arms are made of. I don't know if the arms are alloy, high carbon or mild steel. The risks are greater if the arms are made from a heat-treated alloy.
The following notes are off the top of my head. I'd never claim expertise, or even much knowledge about metallurgy. All steel has a crystalline structure. The type and size of the structure depends on the type steel and how it was processed during manufacture. The structure in a cast part is large and angular, so they break rather than bend. Mild steels and 'worked' steels have a finer structure that allows them to bend. 'Worked' usually means a forming process such as rolling or forging.
The crystalline structure of part changes when it is bent; and straightening a part doesn't restore the structure. Fracture lines and internal stresses may still exist. Actually, I'd go one step further than your dealer and say that simply straightening, heating and cooling a part may not restore it's original structural integrity. The annealing (fancy word for cooling would likely relieve internal stresses though). Basically, a part has to be 're-worked' to ensure that the original structure is restored.
Working steel can be done hot or cold. However, cold working takes much more pressure and time than hot working, which is why blacksmiths have forges and anvils. I think it's safe to say that cold working a part with the cross section of a link arm would require a huge anvil and a power hammer. When working steel by forging, it's the pressure created between the hammer face and anvil surface that counts. It's not just banging something to straight it out. Repairing the arms probably would be a simple job for a blacksmith, but a forge and good anvil would be needed.
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 | Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2001-11-29 33516
My first reaction is "Doooooo" as Homer Simpson puts it so eloquently. Secondly I think my neighbour Tom is on the right track, the molecular structure of that type of steel is such that it allows flex, but is NOT supposed to allow bending, kind of like a leaf spring does. I would suggest that if they have bent very much they should be replaced, there will undoubtedly be structural changes (read weak spots) in those arms now, the only way to tell how much is (short of Magnafluxing or similar NDT or Non Destructive Testing, which would probably cost more than the replacements) after they break. If you use (as you mentioned) a high load implement like a skidding winch, thats probably not the best, or safest thing. Buy two new arms, hand your 'friends' the bill and I bet they won't even be TEMPTED to do it again. Best of luck. ....
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| Eric Edwards
Join Date: Posts: 1
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2001-11-29 33523
Thanks for the replies. I picked up a copy of "New Edge of the Anvil" by Jack Andrews and it basically said what both of you have written. Even if I were to heat this arm up to anneal it, then straighten, harden and temper it, the process will probably increase the size of the grain structure and thus weaken the bar. I'm not sure I've got it exactly right but I agree with you both that it probably won't be close to what it was. I don't know the type of steel but it looks cold formed. As far as purchasing a replacement for the second link which is out a lot less, I may run it the way it is and not try to straighten it. I can't see that this link would actually break but I'm all ears. I actually feel lucky that they didn't rip my top arms right out of the rear hyd assembly. I've been pulling 29' 36" dia at the butt red oak stumpage out to saw up timbers and never bent anything. On a corner the log(attached with one choker) will pivot where it hits against the lower shovel part of the winch. Aparently, they attached the back bumper tight to the winch with two chains instead of just towing it out with one long one. Of course, the first sharp corner they took they must have snapped the sway chain as there if no way those parts could handle trying to swing what they were pulling. As they continued pulling, the winch must have assumed a very odd angle, bending the rest of the components shearing cotter pins on the fork of the lift link on one side. My bill so far for parts is over $400. and another link would add $285. This includes replacing all four sway chains for peace of mind. This doesn't include my lost time or going to pick up the tractor and being surprised by all the damage. They didn't even know! Also, I am using studded ice chains on the rear which gave them plenty of power and no slip. Now I'm venting ! Thanks again for you imput. ....
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 | Art White
Join Date: Jan 2000 Posts: 6898 Waterville New York
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2001-11-29 33527
I hope you charged enough rent to cover the damages. ....
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| BillBass
Join Date: Feb 2002 Posts: 190 North Texas
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2001-11-29 33528
If you know of someone (or maybe a local shop) with a hydraulic press, you could probably at least get them bent back to near normal shape so that every thing lines up correctly. That would be easier and more accurate than banging on them with a hammer. ....
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| steve arnold
Join Date: Posts: 1
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2001-11-29 33529
I bent my adjustable lower link screw as you mentioned, mine
has the spider gear hand crank. I was crossing a small ditch
with my 2-16 reset plow attached (A little heavy for a 970)
as the plow caught the edge of the first bank and my rear tire
went down in the ditch something had to give.
If it's not too late, I would suggest buying the same adjustable
link assembly used on the 990. It looks stronger, simpler, and should
be a direct install.
BTW, Mine is welded up solid now with heavy wall tube stock. This is ok
but I had to put it in float mode to help connect implements. ....
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| bullworker
Join Date: Feb 2002 Posts: 22 western mass
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2001-11-29 33537
my experience with parts of this nature has been to work them back with a press.the type of bend has a lot to do with how much strength will be lost in the piece. a long gradual bend can usually be taken out without much loss of strength , a sharp bend that has stretched the grain of the steel is a little harder to repair if at all, and there will be some loss of strength but still may be ok if used properly. some caution should be used when pressing steel that may be hardened but since these have already bent and not broke it should be ok to attempt to straighten them . hardened steel can shatter and cause injuries. ....
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| Roger L.
Join Date: Jun 1999 Posts: 0
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2001-11-29 33538
I am going against the grain here, but I don't see a problem with a repair. First of all, the chains and chain terminations are probably a high strength steel, so they won't repair well. They have done their job and should be replaced. The rest of the parts 3pt parts that you mention are likely to be a mild steel and can be heated, bent, and rebent without any problem at all. Mild steel is easy to work and forgiving. Loss of strength will be minimal. There isn't any reason to use high priced alloy or heat treatable steels in those areas. Mild steel is good enough for those parts and if the member isn't strong enough, the designer will use more mild steel rather than go to an higher yield strength and higher cost type. After all, he isn't constrained by weight or space limitations....which are the main reasons for going to a specialty steel. Besides, even if it turns out to be HS steel, any half-way decent welding shop can quickly tell you which parts are of steel that they can work and how to do it. Loss of strength would be through cracking and this is easily seen when hot. And even if there are cracks the welder can partner in some steel to beef it up. This is a tractor; not a piano. I just do not see this type of a repair as a problem. ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2001-11-30 33547
Roger: I really don't think you're going against the grain (great potential for a dumb pun here). I believe what you say is true in the case of mild steels, and lift arms probably are mild steel. I think automotive steering parts also are mild steel, because as you say it is forgiving stuff. I think the value of this type of discussion is that it illustrates the risks of repair. Mild steel as well as any other develops fracture lines and break rather than bend.
I have the sense that repair is most likely feasible, but should be done be a shop that really knows what they are doing. One of the original repair ideas seemed to be along the lines of banging the arm out straight; then heating it up and letting it cool. I think there'd be agreement that such a repair wouldn't be adequate. Trouble is that a good repair like you described might cost about as much as a new part unless a person could do it themselves. For myself, I 'd probably buy a new one. There are likely people in my area that could do the repair adequately, but I don't know who they are.
Anyway, I might over-react to issues like this. I think I mentioned some years back that I witnessed several fatalities when a truck went off the old highway over Loveland Pass--west of the summit (I figure you've been there). It turned out to be the result of a welded tie-rod. It made a lasting impression on me, and I tend to avoid home-grown repairs in critical applications. I think that any discussions that illustrates the risks of things, and that adequate repairs often require equipment and skills that ordinary owners lack are good.
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| Roger L.
Join Date: Jun 1999 Posts: 0
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2001-11-30 33548
Tom, you bring up a good point which is that the person who knows a good repair from a poor one is likely to be the very person who could do it themselves. The only solution that I know is to get advice from a knowledgeable friend on what shop to use.
It is a basic tenent of metal design and manufacture that a welded joint has the same strength as the base metal. If in doubt, then strength is added with additional metal. My experience is that most welding shops are good with their work. I do draw a distinction between a welding/metalworking shop and welding repairs that are done at a mechanical shop.
As you say, application rules here. With some thought, I might weld up a steering component on my tractor, but I wouldn't even consider welding the same part on a vehicle to be used on the public roads. But my opinion is that 3pt components fall into a different category of risk. I wouldn't hesitate to repair them.
Yes, I do know that old road over Loveland pass - now Eisenhower tunnel....used to ride my motorcycle over that pass a couple of times a year. Nice ride. ....
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| Eric Edwards
Join Date: Posts: 1
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2001-11-30 33554
Just to get back, this is where I am. I have received all the parts that I ordered. When I dissasembled the adjustable gear lift link the thrust bearing was distroyed and so I had to order that part yesterday. The two guys using my equipment are machinists with a Yankee; we can fix anything attitude. So they brought out the sledge hammers and straightened out two draft links and one lift link fork. They dissapproved of the parts I purchased as a waste of $. Fact is, I just want what I had. A known structual integrity as I'm not done pulling logs or anything else. They actually wanted to try and fix the bent threaded rod with gear machined on top for the adj. lift link ($71.). It would never have been right. I replaced all four sway chains and reused the turnbuckle as the chains were visibly stressed. A chain failure in the future could cause more damage.
I've spent about $500. They also put a couple of large dents on my fuel tank and creased my hood panel. A $35. lamp was damaged on the front and the list goes on. These two have been around small (20hp) compact for years and they should know better. I am hard on my machine and they see that. I v'e never caused any damage even in the woods because I work with the tractor almost every day and have learned how to work fast but carfully. I s'pose they jumped on with to much enthusiasm and tryed to mimic my movements without the experience that time allows. The difference between a 20HP and a 40HP tractor is a big one, but, It's not a skidder or dozer or tank and they just forgot themselves.
Roger, I have actually built grand piano's and perhaps that is my problem.
Steve, not a bad idea but to late I ordered my parts.
The deal was this: My equipment was on a friends lot because of a mutually beneficial arrangement. I would recut roads, take a dozen premium trees, saw them on site with my portable bandmill. I would take the center cut timbers and he would keep the 1" boards. At reasonable market prices, he would alway be ahead by about 20% if I were paying him for stumpage and he was paying me for sawing and handling. He also recieved all the firewood and trailwork as a by product. I allowed him to use my tractor to pull out firewood and let him borrow a key for the mill which he could use after he had a number of working hr under his belt. He's an old friend and was doing me a favor by letting me cut long timber which I don't have on my back forty. However, at this point he won't even discuss money. So I may have to chalk it up to experience, which quite frankly leaves a bad taste in my mouth. So Art there was no rental agreement, just a loose arrangment amongst lifelong friends. I'm not giving up on the friendship, but realize it's a one way street with him. Yesterday he stated basically that he would help with my house project labor wise. This doesn't pay the visa bill however. The tractor was bought used with working capital to serve a function. If it's value depreciates to much, I am the loser. I will not be lending my winch to him for use on his dads Ford 1720 or any thing else in the future and I am unhappy that it has come to this as he could use the help and is basically a good guy. When I use his machine shop I alway pay him for his time. ....
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| Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2001-11-30 33556
Eric, as someone who (for good or bad) has a small fleet of equipment & trucks I receive more than my fair share of requests for 'favours' from friends, some I don't even remeber having. I was taught a trick a few years back by a very dear (also self-employed) friend of my fathers. Reply to requests this way... "Since you're a friend I can do it for (as an example) $500, if you weren't a friend it would cost at least $1,000. When do you need it done?". The people who are true friends (or even just good people) will appreciate the help, the ones who grumble or don't want to pay are not people you want to work for anyways. A deal is one thing, imposing on someone is a whole other kettle of fish. If you are running this as a business, act like it and nobody (who's opinion counts) will hold it against you. Bottom line in my opinion, Freeloaders 1, Nice Guy 0 (for now). Best of luck. ....
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| steve arnold
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2001-11-30 33559
In that case Eric, You might consider having dealer install
the $71 part. It's been 5 years since but there was something
about the lower female part that needed to be done before threading
in new male part. It may have been just my carelessness, but the
threads ended up cross threading and caused a failure under a load. ....
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| Eric Edwards
Join Date: Posts: 1
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2001-11-30 33563
Nice guys finish last but sleep well most nights. But, point well taken.
Steve, you are correct. The lower threaded section on the adj. lift link could be a problem. There is a factory placed roll pin, (I am assuming) by the breakdown in my repair manual, in the end of the male threaded section to keep it from falling apart as you wind down the adjustment to say level a rake. A good thought really as it would be easy to break a foot or just get stuck for hours if an implement landed on you. I'm sure it's happened. The glass hard roll pin would sure mess up those threads if forced out. It was inserted through the grease fitting with the threaded portion screwed all the way down. The guys at JD didn't know how to get it out though and I ended up replacing that part as well. When I got home my repair manual said to line up everything and just tap the assemble on a table. Because my threaded rod was bent badly I had to cut it and then it wasn't long enough to screw down without tack welding a rod to it. The forks were pretty bent so I didn't want to deal with it for $40. My machinist friend could have bored and tapped a hole on the opposing side to drift out the pin but lets face it, I had had enough aggravation and just bought a new one. (those JD manuals are indispensible and lucky for me my tractor came with the complete set.) ....
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