Twisted beam on splitter...options?

[nathan125]

My father in law built a splitter for me as a gift. The beast has a 5 inch cylinder and it seems overly powerful for the beam. It sunk into some nasty elm and it followed the grain and twisted and contorted the beam. I cannot scrap this thing, that is not an option. I don't want it to twist anymore and I have access to a welder for hire.... I want to know what are my option for correcting the beam and how I should go about reinforcing it? The beam is not sturdy enough as is... obviously... I was thinking of at least quarter inch steel plates length wise along the web on each side and underneath flange...on top is not an option either. Any suggestions or ideas are appreciated.

 

[GadDummit]

That's hardly a twist. I'd use it like it is unless it gets about twice that bad based on experience.
I've had some twists or bends that were twice that bad where the blade was even with the edge of the beam. At that point you can either remove and reattach the blade for the new angle (easy) or cut the beam and weld it back together straighter (harder). You will have seams showing with the second method.

The only real way to fix it is to buy a new beam ($500?) and keep an eye on your beam as you're splitting from here out. That's a nice gift you got. I understand your not wanting to hack it up, but if you talk to him I'm sure he'll understand. Just tell him the wood in your area is tougher or something.

 

[kevin j]

to handle torsion twist in that direction it doesn’t do any good ( or extremely small improvement ) to add plates to the center web. It’s still an open section. you want to add plates as far out as you can from the top flange to the bottom flange just in far enough that it clears the slider and make it into a closed box section instead of an open I section that will give you tremendous torsional improvement in resistance. even 3/16 plates with some big holes cut out. you just need to make it into a closed box section

 

[kevin j]

to illustrate this take a piece of printer paper roll it into a tube and put a couple pencil marks where they overlap. grab the ends and twist. and it twists extremely easily because it’s an open flat plate section but you’ll notice the marks slide back-and-forth in relationship to each other which is called shear. Then put a tiny bit of tape on the joint. that turns the rolled up paper into a tube section that can’t move in the shear direction and you’ll see a huge increase in torsional resistance

 

[ABMax24]

For simplicity sake you could get a piece of square tube (HSS) and weld it beneath the existing beam.

But if it were mine I would take and weld flat bar or plate strips inside the web making a triangular cross section. Have it run from the inside top of the beam where the web meets the flange and run it down and out to meet the outside edge of the bottom flange.

Like this:

The existing beam is in black and the new plates are shown in red. I do realize this would require moving the mount for the controls, but this design also wouldn't interfere with the slipper arrangement on the splitter head.

 

[kevin j]

this might actually make things worse. The triangle will be a more rigid section in torsion but the upper joint where everything comes together in the center might concentrate stresses in that area. It might be more rigid, but more highly stressed. The upper end of the plates need to be as far out to the sides as possible and still clear the slider

 

[Sawset]

A couple pictures to ponder.
One end fixed, side load on the other.
If the original is twisting, boxing it in as shown is the most effective way to reduce that.

 

[peakbagger]

If you don't need all the full flange width, boxing in the I beam is the way to go. Of course a light beam has a light flange so you may end up having to repair the remaining flange at later date as you have concentrated the load that used to be on the entire flange to the area of the weld.

 

[Jags]

As Kevin suggested, installing new plates just inside of the shuttle slide area would be the simple solution and go a long ways to stiffen up the torsional strength of the beam.

Peakbaggers (and sawset) idea is probably the strongest in the long run but would require a redesign of the shuttle (to encompass the whole beam, not just the top flange). Do-able but a little more work. With either solution, correcting the current twist should be a high priority.

 

[Sawset]

Small splitter build: http://www.hearth.com/talk/threads/jags-splitter-build-pic-heavy.83540/
Massive beam there Jags.
Might be better (and maybe easier) to just change out the beam in question completely. Call it a learning experience. Would have a solid unit that would last a long time. I know there are a lot of projects that I've worked on that needed an "experience update"

 

[Jags]

Small splitter build: http://www.hearth.com/talk/threads/jags-splitter-build-pic-heavy.83540/
Massive beam there Jags.

I don’t like to bend things that shouldn’t be bent.

 

[nathan125]

Thanks for the suggestions . I have decided to get a new beam welded on. Its 3/8 thick and is a 4x4 beam....the plan is to weld the two beams side by side making a 4x8 beam. This is box in the middle also make it wider so i dont have to cradle the wood as much when it wants to fall off the side. Do you guys think its necessary to box in the sides of the beam also? The new beam is 50% thicker but I never want it to even think of twisting again.....

 

[Jags]

Are you welding the new beam to the twisted one or two new pieces side by side. I was a little confused by the description.

 

[nathan125]

New pieces side by side

 

[peakbagger]

So "II" with a weld along the top seam and weld along the bottom? That will definitely stiffen things up big time.

 

[Sawset]

New pieces side by side

Sounds like a big improvement. I-beams, not S-beam.

 

[Jags]

Got it! That will be quite the upgrade.

 

[nathan125]

is there an advantage to stacking the beams on top of each other and boxing them in as opposed to side by side and welding ? stacking on top may be the easier job I am told.

 

[kevin j]

stacking them vertically will be a huge increase in bending in the direction that the forces on the wedge go. The deflection is a cube term so twice as high is eight times as stiff for bending deflection but not torsion. . Stress is a squared term so twice the height is four times as strong. However it’s still an open section in torsion. So basically you’ll get twice as much in torsion because of the two beams being open section essentially just add together. If you can box it into a closed section putting them side-by-side you probably get five or eight times torsional increase.
that would be a huge increase but it seems like quite a bit of fabrication issues rebuilding the slider , moving the wedge to the center etc. I still think just boxing the sides in is the cheapest quickest and definitely the lightest quick and dirty way to go