Heating a pallet fork

[barbender]

I have a set of pallet forks I bought new about 10 years ago. From the factory, 1 fork has a sweep to it that makes the tip sit a good 2" higher than the other. I should've just returned them when I first noticed, but now that 10 years has gone by🤷🏽‍♂️ I realize these are spring tempered, have any of you ever tried heating and bending one of these? I suspect I'll lose the temper and have a noodle. Oh btw yes I have tried prying stumps and other abuse I can give that tine trying to bend it, but it says, "nah!"😊

[doc henderson]

I have experience making them bent but never have fixed one.  the first set I got, I used to pull out roots along the surface.  the root got bigger than I realized.  they were too weak to begin with, and I sent them back and got the 4k rated ones that I still use.  

[Vautour]

.......Yes i did try to unbend a fork :D.. i tried lifting the back end end my loader by putting a 12"x12" bloke between the fork and rear but came back as it was and was getting very dangerous ... the simple solution is to weld a proper thickness plate to the heal of fork and vola... i've done this to two sets of fork.

[Skip]

Very bad stuff can happen when trying to "rebend' bowed forks, 

[YellowHammer]

I wouldn't heat the fork.  
My tractor dealership has a huge hydraulic press, and routinely straightens forks without heating.  You might make a few calls, or call your local forklift shop.

I have rebent the tips of mine with my hydraulic press, but don't have the tonnage to bend the main bodies of the forks.

As with any hydraulic press operation, safety is paramount.

[Oliver05262]

I've been down this road before. A long story but a friend who is now running a WM LT70 wide mill is using a wheel loader in the yard. They had a big commercial operation a while back running two big band mills and always used I-H Hough, and later Dresser loaders of the 520 size. When the mill burned, they lost the loaders too. When they restarted, they bought a used 520B since that's what they were used to. The 2"X4" forks that survived had been adapted from JRB to fit the ACS coupler on the machine, but one fork had been broken and welded back near the coupler. Frozen in the ground logs finally bent that fork, and we went through the process of welding on a block to even them out. The fork finally broke and showed where it hadn't been vee'd out and properly welded. He had a good welder come in and he fixed it right, and I took the spacer block off.
   The old Dresser loader finally gave enough trouble that he traded it off for a used Doosan loader, even a bit bigger in size. That fork has broken and been welded again, and he may have to buy a new set of forks that are a little stronger maybe 2 1/2"X6" someday. He did have a shop with a big press try to straighten them once, but they had no luck. The welder guy cut the weld out and vee'd both sides, did the pre-heat thing and used wire equal to 11018, but that steel just didn't  co-operate.

[Southside]

Are forks forged?  If so I am thinking you could never re-weld it to the original strength.  

[sawguy21]

I would not take the chance on fork steel. Somebody blew a hole in one so a shackle could be attached to tow aircraft. They were lifting a transmission via cable when the fork let go, it wasn't pretty.

[Vautour]

 

 

[Resonator]

I would say replace it, you might be able to find a used one fairly cheap. (I know in Wisconsin of a certain "big-box" hardware store that resells there used ones). Besides, then you wouldn't have to change your name from "Barbender" to "Forkbender".  ;)

[donbj]

From a Work Safe or Workers Compensation perspective if you even look at a fork with a cutting/heating torch or welding rod in your hand you'll get in trouble. Same context as ROPS or any other safety related structures. You will need clearance from an engineer that built it before modifying.

[Oliver05262]

Vautour, we shimmed out our fork like that, but the weld across the fork causes a stress point that really weakens the fork. Just tacking the shim on the vertical side is better; even safer would be to bend a strap to hold it against the fork and only weld to the shim.

[barbender]

That shim idea may be the most viable, I'll have to take a closer look. The one problem I can foresee is that these skidloader fork frames hinge at both the top and bottom- they are kind of fixed in place. So I don't now if there will be enough slack to shim the one out. The fork that is defective has a long upswept curve to it. Believe me, I've tried to bend the dang thing prying on stumps and any other opportunity that comes along. The max lifting capacity of my machine can't touch it🤷🏽‍♂️

[Vautour]

@
Oliver05262 ...i agree .. i was more concern about the little bracket that holds the fork there.. vertical welds would do just fine..tks for pointing that out.

 

[longtime lurker]

It's hardened steel - you heat it you change the metastable martensite into austentite and it will keep bending in the same place again and again. ( martensite and austentite  are different ways that carbon forms in steel.

The only way around that is to heat, bend, then harden and retemper. That requires  taking it to yellow hot across the whole thing, a quick quench, and a temper..... you can do it at home - colour charts for steel are widely available online - but for best results you need a competent blacksmith. Blacksmiths have forges, which are pretty much essential to get that area of steel to a consistent temp anyway.

[barbender]

LL, heat treating is the part that concerns me. I didn't know if they were actually spring tempered, or annealed. I've done some diy home heat treating for small woodworking gouges and such, but getting a whole fork yellow hot and quenching is beyond what I want to get into😁

[longtime lurker]

Well we do have wood, and from.wood we can get.charcoal, and with charcoal and a compressor for air...

Yah I'm the same. Theoretically I could do it, I've done small bits and pieces but it's a bit big for me also.

Maybe an auto/truck spring works. A lot of them are smith's or have contacts who are. If you can handle a leaf spring you should be able to do a fork tyne you'd think.

[YellowHammer]

A local body shop may have enough of a manly hydraulic press to straighten it out.  Any steel shop would be able to do it.  I think it is a routine process.  I would be very hesitant to heat and re harden.  

[charles mann]

I too bent a fork and was thinking of doing the heat and bend method. But the shim method might work. Ill use a 2 part petroleum resistant rubber epoxy to bond the shim. Once cured, it wont fall off for many many many yrs, if at all. Surface prep is key though. Scuff the surfaces of both fork and shim, clean with acetone, apply enough sealant (pro-seal 1422 b 1/2 or 890 b 1/2) to ensure squeeze out once clamped and squeegee the squeeze out around the edge and let cure for 4-6 hrs, then instal fork. 

[Corley5]

Bend the other one to match ;) ;D

[charles mann]

Bend the other one to match ;) ;D

I tried that. Cant say for others though. Attempted to pick up the same end, of the same log and all it did was lift the rear of my tractor. 

[barbender]

I've tried, Corley!😊 I don't remember the weight rating on these forks, I do know I bought a heavier duty set. It amazes me what abuse quality forks can endure!

[Al_Smith]

I've got a buddy with a 200 ton press but the trip would be a long one .All I have is an 80 ton rating Greenlee 785  gigantic tubing/pipe bender and I don't think it would   .It will bend 6" pipe though .Cold bending it will take some tonnage .

[Larry]

LL, heat treating is the part that concerns me. I didn't know if they were actually spring tempered, or annealed. I've done some diy home heat treating for small woodworking gouges and such, but getting a whole fork yellow hot and quenching is beyond what I want to get into😁

I think it possible to hot bend the fork back straight, but than it would have to be heat treated to regain strength.

To heat treat you need to bring the whole fork up to a red heat where the steel is non-magnetic.  Than quench and finally temper.

The problem is there are lots of different quenches ranging from fast to slow.  Water, various oils, and air.  I'm sure there is only one proper quench for a fork.  Next problem is tempering.  How long and how hot?  Different properties for each grade of steel.  I think to many unknowns to repair with heat.

Welding is also a bad idea because of the carbon content in the fork steel.  The welding could also cause problems in the HAZ (heat affected zone).

I think the only solution I would trust is bending it back cold.

[barbender]

You guys are confirming what I already suspected to be the case. I might try to find another big stump, or maybe go try to find a shop that has a monster press. There's outfits that service the iron mines near me, might be something there.