Repair of 12.5 Ton Log Splitter

[Don52]

In 2010 I repaired the slider bracket that attaches to the ram on my friend John’s 12.5-ton log splitter, which was 1-1/2 years old at the time. In addition to full penetration TIG welds, I also increased the length of the diagonal brace. I believe that the root cause of the failure was a defective cold lap weld. Do you agree? The repaired bracket has held up 11 years and is still going strong after splitting thousands of logs.

1. Damaged Bracket on Log Splitter


2. Full View of Broken Log Splitter


3. Cold lap on right side


4. Rusted cold lap


5. Outside Weld

[Don52]

6. Side weld


7. Bracket All Done


8. The bracket today - 11 years later


9. Full view today - 11 years later


-Don

[mla2ofus]

Good job!! The crappy factory welds were a big contributing factor. Maybe a little grease on the under side might have prevented this.

[Louie1961]

Nice repair. Certainly looks like cold lap to me.

[SlowBlues]

Great work. Your Repair/upgrade is much better than the original.

100% Agree about the causes, cold lap first and relatively bad design second (though it may have been adequate with a good weld). Looks like major cold start/lap that the crack started at, and ripped through the weld bead where there was penetration. The cold lap was not helped by the difference in material thickness, and the likely orientation of the weld when made (thicker material on the bottom, thermal dynamics working against you).

Having the vertical brackets run the full width of the horizontal piece (like your repair) moves the weld stress from purely shear (relatively weak) more to tensile (best for welds), in addition to helping box in the assembly (more rigid). Good lesson in simple, small changes that can make a big difference.

[Willie B]

Kind of a tender machine in the first place. Mine, homemade in 1981 has about a foot long box that rides the flat plate. It's a good deal heavier built than yours.

No easy way to extend the length of the portion that slides, so to avoid it binding like a sticky drawer, lubricant is essential. I use bar & chain oil on mine.

Having suffered a life threatening injury from a block of wood that jumped out of a splitter, I have a series of nuts welded around the perimeter of the push face.

[geezer]

I had a similar cold lap joint with a loader bracket on a tractor. Cant locate then picture, but the bracket peeled off due to lack of factory fusion. If i find the pic will post it

[farmersammm]

Funny thing about a fillet weld.

It's never truly in tension, or shear. It's the nature of the beast.

Transverse loading is the strongest orientation. Which the log splitter ain't......no matter how much bracing you add.

As a matter of fact, the splitter thing is in shear 100% if you discount the hinge on the leading edge weld. It was the shear that caused it to fail, and it still exists.

To get around this, as has been done, build the joint overstrength. It works, and is totally acceptable. But don't talk about shear/tension unless you're fully versed on the situation.

[Willie B]

Funny thing about a fillet weld.

It's never truly in tension, or shear. It's the nature of the beast.

Transverse loading is the strongest orientation. Which the log splitter ain't......no matter how much bracing you add.

As a matter of fact, the splitter thing is in shear 100% if you discount the hinge on the leading edge weld. It was the shear that caused it to fail, and it still exists.

To get around this, as has been done, build the joint overstrength. It works, and is totally acceptable. But don't talk about shear/tension unless you're fully versed on the situation.

I ain't as smart as you. I look at successful splitters, look for the differences of good vs. broken. I'd prefer to see a longer interface between beam & slide to avoid sticky drawer binding. I can't say whether galling is evident. Unless you only split consistently sized wood cut perfectly square, there'll be some cockeyed strain.

[farmersammm]

I ain't as smart as you. I look at successful splitters, look for the differences of good vs. broken. I'd prefer to see a longer interface between beam & slide to avoid sticky drawer binding. I can't say whether galling is evident. Unless you only split consistently sized wood cut perfectly square, there'll be some cockeyed strain.

Absolutely, and don't give me that "smart" horsecrap. You got your act together.

The bind is key. If the thing twists (can't say co$cked because the software edits it). Put the thing in a bind, and it stresses everything on down the line.

[farmersammm]

Log Splitter Done
the
Kieth Fenner way

Lookit the bearing plate on that thing..............it's long. It's the way stuff oughta be built.

[farmersammm]

And, if ya look close..................the cylinder rod points down as it moves. Places the stress against the beam, not against the bearing plate

[SlowBlues]

No one said the weld was purely in shear, or purely in tension after the fix. Just that it shifted in that direction.

I'm well aware of the forces enacted upon a fillet weld, and like you have a very well read set of lincoln handbooks.

The best way to look like an azz about most technical things in real world applications is to talk in absolutes.

[farmersammm]

No one said the weld was purely in shear, or purely in tension after the fix. Just that it shifted in that direction.

I'm well aware of the forces enacted upon a fillet weld, and like you have a very well read set of lincoln handbooks.

The best way to look like an azz about most technical things in real world applications is to talk in absolutes.

Years ago, I had a failure in a fillet weld. I looked for every source of information I could find as to how it might have happened.

My initial impression, or guess............lamellar tearing. Near as I could tell, the metal beneath the weld had torn, not the weld itself. I ruled this out.

Then I started to look at the possibility of cold cracking.....................The weld failed almost immediately when it was put in service the day after it was made. It was a multi pass fillet weld connecting 1" plate to a 3/8 base plate, which was solidly welded to a 4" square tube frame. A "T" butt joint. No preheat was done. BTW, this was a hydraulic cylinder pin lug on a piece of equipment that takes a huge amount of abuse. The cylinder has a very bad angle.........about maybe 4* from being in a bind,, and the cylinder is run to a stall at all times when using the piece of equipment. It simply can't push anymore, and comes to a standstill.

Ultimately, I decided that I was looking at cold cracking...........Hydrogen induced cracking.

The weld was highly restrained, with no preheat. Even though the weld was made with a lo-hy rod, restraint can cause hydrogen cracking. There's alway a certain amount of hydrogen in any weld, and restraint while cooling can exacerbate the problem.

Then I looked at the lack of a preheat. Preheating reduces cooling stress on the weld, and allows more time for the hydrogen to escape from the surrounding metal , because hydrogen will migrate to the atmosphere from the metal at around IIRC 700*, and above. The longer the amount of time the steel remains in the 700* range, the more hydrogen is allowed escape. Less hydrogen, less possible embrittlement. I took this with a limited nod of acceptance. It was the best answer I could come up with.

From what I can understand, there are 3 factors. Metal susceptible to hardening, highly restrained joints, and hydrogen introduced by the consumable. Limiting a couple of these factors will help eliminate underbead cracking.

Anyways..................when repairing the weld, I ran a preheat of 400*, which is well within safe limits. I believe that the limit in seismic zones, on structural steel, is around 600* I take that as the limit for any kind of weldment.

Same restraint conditions, same multi pass weld, but an added preheat. Weld is still functioning to this day, after a lot of abuse.

Now to the stress discussion................................

While looking for the cause of the failure, I looked at the stress acting on a fillet. Nothing fancy, just a pretty simple discussion, in what I thought was a very concise presentation aimed at someone like me......not an engineer.

Transverse loading is considered a tension load (to a certain extent) https://weldinganswers.com/how-to-de...e-fillet-weld/

Shear loading is when the stress is at anything other than a strict 90* perpendicular load................and the article states that fillet design is always done with a shear load as the base point. It's assumed the weld is in shear. https://weldinganswers.com/how-to-de...a-fillet-weld/

I'd always wondered about fillets, and just looking at them, you can see a multitude of forces acting on the weld. The article introduced me to the concept of de-rating a fillet. I've mentioned it in the past. It's a very handy thing to know.