I visited a good friends sawmill today to see what he is up to. We always like looking at welds that either employees made or subcontractors do. He took me back to their shop and showed me this forklift fork that was broke the other day. He began to explain that this happens often enough that they keep a spare set and when one fork is being repaired they can put another one on. I told him I would post this here to pick everyone's brains for a solution and how they would repair it. Now before we get to far know that the employees are very rough on equipment so purchasing new forks every few months is out. He said that it is especially bad in the winter when they are trying to dig logs off the ground that are frozen. As you can see, this one was "repaired" and had plates welded on the sides to help. You can see that they already torched them apart where it was still attached. It appears that there was absolutely zero penetration on the sides. Before suggestions are made know that they only have .035 ER70S-6 MIG and various SMAW electrodes, including 7018 that has more water in it than the pond
I suggest they cut off the side plates and torch out all existing welds and start fresh. Full pen welds will be required and I would use brand new 7018. I asked if they ever pre/post heat and they said no. I also suggested pre-heat to 250-400* and hold that as inter pass temp and post heat with a slow cool just like you would for cast. One concern I have is if these are forged steel, what would the constant heating, welding, torching be doing to the molecular structure?
Also, from the research I have done, forks can be repaired if the manufactures WPS is followed and signed off on repair. I say good luck getting them to give you a repair WPS!!
-Jonathan
Id walk away as well, even it if was a buddy. For private use if you wanted to fix and use its one thing, but like the others it is too risky....and in many cases illegal to repair forks. I know it sucks because of the cost but like Steve, Id ix the root issue or look into another method of grabbing the logs.
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I don't think Jonathan is repairing, was just showed it by his buddy.
I would suggest using something like some railroad ties to keep the logs up off the ground.
One well built set of forks should last forever.
I worked at a place that broke a set of forks after about 20 years of use, probably fatigued them right out. The welder did His due diligence and researched welding them. Did the pre and post heat. Went to lift up the first load at capacity and the forks stayed on the floor. I trust the Welder and His work, this time no success.
You are correct, I am not repairing it and yes it will be repaired. I just wanted to pick everyone's brain and see how they have repaired a fork in the past.
-Jonathan
As I understand it (and I'm happy to be corrected) the fork is forged, then hardened and tempered in one piece in an oven designed for the purpose.
This will be difficult if not impossible to replicate in the field, and any weld with any filler will create a HAZ.
I'd think a very high pre-heat, to reduce the local heat needed, dry 8018 rods, and a quench in oil (used motor oil will do) will give them the best chance for durability.
I still lean toward a root-cause solution, either eliminating the need to try to pry logs from frozen earth, or the right equipment for the job.
Never done forks, but had fairly good luck repairing ripper shanks using pre/post heat with no quenching and 8018 rod. I'm with the others here, though, in thinking it's a bad idea to repair old fatigued forks. With a ripper, if it breaks it's an inconvenience. Forks breaking seem very dangerous to me. That being said, if they insist on repairing them, I'd suggest they cut away all the crap from old repairs then use a good preheat and 7018 or 8018 electrodes. imho, ER70S6 is not strong enough. I also would be hesitant to quench it, opting instead for a slow cool with some post heat.
We are not lawyers nor physicians, but welders do it in all positions!
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A fellow up the highway from me sells used forks. His story is that OSHA rules require they be replaced periodically in some critical situations. Farmers buy them and alter them to fit loaders. A set of forks built for 5 tons can lift 1.5 tons without effort. I'd say don't fix them. Since they are going to do it anyway, cut away the entire heat affected section, use a donor set to replace the now too short fork. Avoid filler that is too hard, it will break again. Softer filler (70or 80) will be soft but less likely to snap. Capacity will be reduced.
Cherry picker steel is soft as butter, I guess so it won't break. It takes a lot of smashing without breaking.
Have they considered plating the top with a layer of 1/2" to give it a truss effect? This would place most of the old steel under pressure not tension while lifting.
Otto Nobedder wrote:As I understand it (and I'm happy to be corrected) the fork is forged, then hardened and tempered in one piece in an oven designed for the purpose.
This will be difficult if not impossible to replicate in the field, and any weld with any filler will create a HAZ.
I'd think a very high pre-heat, to reduce the local heat needed, dry 8018 rods, and a quench in oil (used motor oil will do) will give them the best chance for durability.
I still lean toward a root-cause solution, either eliminating the need to try to pry logs from frozen earth, or the right equipment for the job.
Steve S
Agreed.
Also, the root-cause solution was the first thing that came to my mind as well, just from seeing the thread title.
Seems to me that the parts would need to be welded with the same alloy that it is made from, then the entire part annealed, re-heat treated, and then tempered/retempered a couple times at least, and then flex tested against a good fork. By then, you have probably paid for two new ones.
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Forks can be repaired. And I know an effective method.
That being said there is no OSHA approved repair or a code procedure to follow etc.....
But here it goes. Plan on an 8-10 hour day to achieve a proper repair.
You must use 11018 rod or comparable wire. Avoid using a torch on the fork if possible. Do not pre heat or post heat the fork. Bevel each end to a double v groove with no land. The first pass must be welded open root, 1/16" gap will do. Put the first pass in and use an air hammer to peen it down immediately. You will need to peen every weld right after you are done with it. Grind down the first bead until it is smooth not showing any edges (wagon tracks). Then put a cover pass on it and peen and grind the same way. Flip the fork over and grind out the other side of the root weld the same way then put 2 passes in just like the other side making sure you peen and grind correctly leaving no chance for slag to remain behind. Now you have a strong base built for the rest of the repair. Alternate sides between beads still peening each bead thouroghly with the air hammer and grinding if necessary to ensure no slag will be left in the joint. Build up the fork past the top and bottom then build up the sides of the fork if necessary still alternating sides peening and grinding wherever necessary. Build the sides up past the original fork then grind down all the excess welding making sure there is no undercut anywhere and touching up where it is needed. When you are done wrap the whole fork in blankets to hold the heat in and allow it to cool very slowly overnight or even up to 24 hours.
I know a guy who has been doing this for 30 years and he rarely has one fail and when one does it is usually misuse rather than a bad fix. He even replaces the front foot or so of forks sometimes this way. He has a certain grade of steel he buys that holds up as good as an all new fork.
Disclaimer: I will take no responsibility whatsoever if you choose to use this method to repair a fork on a forklift. I am simply making a statement about a process I know works for such a repair. It is totally in you the readers hands whether you choose to use this method and you assume any and all responsibilities of any and all things that could happen after your repair.
The insurance liability nightmare alone should scare you away from an in shop repair on lift forks!
I spent too many years in a Naval shipyard and we always sent forks out to be repaired even though
we had the right equipment to properly test them.
That said I did get to read the procedures for the repairs and they are preheated and post heated. 11018
200 F preheat and a max interpass heat of 300 F with designated cool down for carbon arc, grinding and mt testing.
Then after the second side is completed there's a post heat cool down procedure.
Then they're ground, polished, MT'd, X-rayed, stress tested with weight and re MT'd ans X-rayed.
Only then does the testing lab certify them for safe use. Weld, grind, drill or alter them in any way
and the certification is null and void. Ours always came back stamped by the testing lab.
Getting them tested and certified after a repair would be ideal. This guy has been doing it for so long he doesn't bother. The only thing I see different in procedures is the preheat. But just because it can be done doesn't mean it should or shouldn't be done. Safety is first and cost effectiveness can also be involved after that. This guy can fix forks for a fraction of what they be bought for even if he'd pay for them to be certified. That is why he does it and he does it often.
I'm not trying to put a downer on this BUT - if you weld a fork & at a later date it breaks causing injury / death which is quite possible there will be an investigation ( unless it was only an immigrant involved ! ) it may be that the fork has been misused or grossly overloaded & so not really directly the fault of the repair but once it is the hands of lawyers someone must take the blame - the owner is going to say he had it repaired in good faith & the welder assured him it was 100% so they will go after the guy that did the repair - he has no one to blame & his liability insurance cannot cover a repair made that was not properly performed to a code / WPS that they approve of - naturally they will say they never approved such repairs so your welder is going to be hit with a huge fine at best or quite possibly do time - it's just not worth the risk unless you do this without paperwork - ie make sure no one witnesses you do the job - do not appear on CCTV on their premises & get paid cash - if anything happens deny ever being there !
As I outlined this is high risk unless you are going to have it certified by a competent lab or testing facility. Then the liability is on their heads not yours because they certified that the repair was done correctly and it will hold. Without that then yes all culpability is on your head and in the event of death dismemberment injury or property damage it will fall on you. No insurance will cover you without the lab tests to back the repair and money will run from your hands like water and you will likely get a visit to the link. I was asked to post the procedure by the OP. I'm not trying to say this should be done I must stating that this works for many folks in my area and this guy knows how and he told me the procedure.
I want to thank EVERYONE for their input. I have been in vacation and did not have good Internet access. Like I said earlier, I understand the liability aspect of this repair and appreciate everyone's concern. There are many things that probably shouldn't be repaired but they are. I personally see no reason a fork can't be repaired IF the weldor is qualified and a procedure is known.
This was "fixed" and I saw some pics of the repair. Lets just say it won't be long until it breaks.....again. Let me also remind everyone that the root cause is in fact abuse so it will not matter if it was repaired correctly.
-Jonathan
I agree with nickn372 repair procedure. I work for a construction company that has around 20 forklifts and we repair about 2 a month do to abuse. We use almost the same procedure for weld repairs except we use a 10018 rod. Very rarely do we do a second repair do to a bad weld usually like someone said in winter when everything is frozen the ground and yes we pile everything on railroad ties but is amazing what a little frozen water will do. We have a large hydraulic press that works great on bent forks, no heat just bend'em back.
I drove fork trucks for years and don't recall ever seeing a broken fork. We made large steel buildings and yes they got some abuse. I've always looked at from the viewpoint of what's the worst that can happen. In this case I'd decline the repair. I've had to talk sense to a boss before, usually when you explain the downside they get it. That said, I've welded things I shouldn't have.
From the looks of the original repair, I think if the fork was properly prepared, beveled & preheated, they could have gotten a stronger weld from a 110v flux-core welder. Looked like they just covered the break.
Here's a thought, and I'm ashamed it took me a minute...
If the forklift is powerful enough to break a fork, there's a mis-match in the system somewhere.
Either the fork was inadequate or previously repaired inadequately, or was not designed for the forklift it's on.
The hydraulics should have strained and stopped before the fork broke. The fork is NOT intended to be the weak link. The hydraulic pressure/piston size should set the limit.
To break a fork is a warning sign. Something is VERY wrong.
Steve, most forklifts get broken due to a loose nut behind the steering wheel.
Just for example a 5000 lb forklift is built to be able to safely lift and carry
5000 lbs on a pallet with the load evenly distributed on the forks with the
max load as close to the carriage as possible. Now when some hotdog tries
to lift 5000 lbs at the very tips of the forks the hydraulics can handle that load
but, due to the added leverage, the forks are in trouble.
Machine design fault? No. Operator design fault. Seen it a thousand times
back in the shipyard.
And it fits the example the OP gave... trying to dig a log out of frozen earth means stabbing the log with the tips and lifting. That's extreme stress on the end of the forks.
