Why Are Laminated Bars Less Durable?

lxskllr

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Aside from generally being more cheaply made, it doesn't seem like they have to be. Steel's steel, right? What am I missing in the equation? I'm thinking about light bars particularly. Instead of milling out a solid bar and filling it with epoxy, why not a slotted core leaving the holes unfilled, and covering them with the sideplates? Seems obvious, so there must be a reason it isn't done that way; on pro bars anyhow.
 
I think Oregon had an aluminum core layer in light weight laminated bars. I've seen the laminations start to separate on one.
 
The welds can break, and there's overall less structural integrity when there are 3 layers spot welded together in only a few places.
 
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  • #5
What happens to a light bar when it really gets tweaked? Seems like the inserts would pop out. I'd also think it would be harder to straighten if one was so inclined.
 
I tried twice to straighten a laminated bar by hammering, no press at home. It's doable if it has a slight bend, but for a serious one, that doesn't work ( my ms150T unclipped from it's lanyard while aloft, with a 2 days old bar, of course). Each layer works separatly between the weld spots but together at the spots. So when I flattened one place, the bend migrated nearby one inch or so. Hammering the new place, the bend came back at the previous location. Trying to make an average by working on the both places, I just go that, an average : a not so sharp bend but wider. The new bar ended in the trash box.
 
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  • #7
Regarding the "Not all steels are created equal". That was kind of the question. I don't see why a laminated bar can't use the same steel as a milled bar. Marc made a good point about straightening a laminated bar, but I wonder how different that is from straightening a light bar. Both are delicate by design. I'm not sure you get a light bar back to a usable state if it really got tweaked.
 
“I don't see why a laminated bar can't use the same steel as a milled bar.”

They could possibly be the same steel but I doubt it. I’ve only seen laminated bars on homeowner grade saws so my guess is it’s cheaper to produce plus a cheaper grade of steel. This little 550xp I just bought has a solid bar and replaceable nose and hardened rails. Supposedly a pro saw. The bar has a “pro bar” price too.
 
It has to do with flexibuilety, weight and costs.

Most laminated bars are spot welded. The glued ones don't take much beating.
When laminating they often use a lighter, material in center.
They tried make holes in solid bars that was filled with plastic, epoxy or alumium, but as the bar move the blocks let go.

Solid bars move less.
 
I guess that machinability and weldability play a big role too. This can lead easily to select an other alloy.
Both are delicate by design. I'm not sure you get a light bar back to a usable state if it really got tweaked.
If the light bar is made by milling, the resulting steel plate is still homogenous and should respond predictabily to a constrain/deformation. Therefore, putting back in shape should be way easier. At the exception of the resin inserts which could broke or separate from the steel, but it's less of a concern (in my view at least).
 
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  • #12
So far, so good! Probably more a matter of luck and lack of hours than any particular skill though :^D
 
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