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Old 12-01-2011, 04:26 PM   #21
kieth
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Join Date: Sep 2010
Location: Tulsa, Oklahoma
Posts: 1,925
Re: X Member Design and Frame Bracing- '66 C10

I understand that we are not hauling a lot of weight per se, but if the frame is more rigid then it will have less flex to begin with, The cross bracing will work better if the outer beams of the frame are stronger, of course the additional x bracing will add rigidity but so will doubling the frame. ps no matter what they say I still do not like welding a frame.

I think our frames are made out of mild steel (55,000 psi yield strength) Newer big truck frames are made from 110,000 psi yield strength material, one could add full U or L channels made of this harder material and bolt it in place and have a really strong frame.

Since I want to add full C channels just like the std frame the picture that you show of the twisting of the frame would be different since the flanges help it to resist twist (some work on the way our crossmembers are attached or adding more crossmembers would also help in this torsional rigidity.) The X bracing sure will help also.

Want you guys to understand I was not trying to pick a fight just get more information out there and make us all think a little bit before we dive off and do things in a way that mght do more harm than good. i.e. welding to the frame, adding bracing in certain areas can lead to a frame failure right where the reinforcing stops.....due to the weld. We always try to spread out the loads on the frame by adding more material all the way to a area that has more reinforcing above the rear axle or to the center above the axle . by doing this we keep the loads in areas that see the least twist.....

If you double frame a truck and stop the reinforcing material right behind the cab of the truck, that is where the frame will fail......if you take it forward to where the frame sees less loading (twist) it will not have that problem...

bolting it together is stronger than welding it. If you do weld an area of frame together, then add a diamond patch, it is still better to do a bolted in longer u section to the front and rear of the weld. This is done so the weld does not see loading where the heat treat has been removed. Bolting the frame together spreads the loads out to the web of the frame instead of to the flange.

Last edited by kieth; 12-01-2011 at 04:52 PM.
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