i guess nobody here know what to use??
Can you please elaborate on why not to use solid rod?Do NOT use solid rod. Use 1020 cold rolled mild steel, with .120" wall. I would go at least 3/4", preferably 1" for the OD.
Does heating the rod cherry red to bend the legs affect the strength?If it's solid rod now, and it's working, maybe 5/8" solid rod?. If so, use 1018 cold rolled, not A36 hot rolled. It's stronger from the cold working process and you don't have to deal with mill scale.
Bob
One should never say never, but if you do it correctly any negative affect will be minuscule. Make sure you don't heat it any more than necessary, make the bend slowly, and let it air cool.Does heating the rod cherry red to bend the legs affect the strength?
That myth continues to be perpetuated. If one believes the assumption that a tube is stronger than a solid bar, then one has to believe that a tube gets stronger as the walls get thinner. Or conversely, the nearer to solid that a tube becomes, the weaker it gets? Illogical and incorrect. One of the elements that contribute strength to a round section structural member is it's cross sectional area. All else equal, the thicker the wall section, the stronger the member. Given that basis, a solid round bar can be thought of as a tube with a wall thickness equal to it's radius, thus providing the maximum cross sectional area for it's diameter. In addition to the beneficial mechanical properties gained through wall thickness, as tube increases in wall thickness, it gains resistance against collapse from lateral loads when under compression. A rod will bend. A tube will buckle.Solid rod is not as strong as tube. Solid rod is more susceptible to bending than tube, since the walls of the tube make it structurally stronger than solid rod while maintaining enough flex to prevent cracking. Plus it's lighter, to boot.
You'll be fine with solid 1018 round, and it's the best choice given your lack of a bender. As for your habit of overkilling things, it's the thing to do if you're unsure about the stresses involved and uncertain as to the correct material. Beats under engineering every time!i really dont know what to use and i have a habit of overkilling things.
That myth continues to be perpetuated. If one believes the assumption that a tube is stronger than a solid bar, then one has to believe that a tube gets stronger as the walls get thinner. Or conversely, the nearer to solid that a tube becomes, the weaker it gets? Illogical and incorrect. One of the elements that contribute strength to a round section structural member is it's cross sectional area. All else equal, the thicker the wall section, the stronger the member. Given that basis, a solid round bar can be thought of as a tube with a wall thickness equal to it's radius, thus providing the maximum cross sectional area for it's diameter. In addition to the beneficial mechanical properties gained through wall thickness, as tube increases in wall thickness, it gains resistance against collapse from lateral loads when under compression. A rod will bend. A tube will buckle.
I'm not arguing for the use of solid rod as a substitute for tube, as the choice will depend on application and material selection. Using tube often makes sense from a weight/strength viewpoint, but in no case does a tube have an advantage over solid solely in strength.
Bob
Not the case at all, and I'm sorry if you misconstrued my intent. My argument never was about whether tube or solid was "better". It was a response to your assertion that tube is stronger than solid. I took exception to the statement, and presented what I thought was a valid counterpoint. Like you, I'll say no more. Peace.So if you aren't advocating one material use or the other, basically, you just wanted to make sure people knew you thought my response was wrong.