Im wanting to make a 1-1/4" sway bar, straight with no bends and use bladed ends. I want to know two things: what material and wall thickness should i use and when i weld the collars on the end will that ruin the heat treat for the whole bar or does it matter because its right at the end?
Size and thickness will depend on your application and packaging.
For the ends, rather than welding do you have the ability to press the ends flat? The HAZ from welding will absolutely affect the treatment of the stock for some inches.
Get a splined bar and attach splined arms to it. You can buy the bars in a variety of diameters and lengths, same with the arms.
For example: https://www.portcityracecars.com/collections/front-suspension-sway-bars-mounts-splined-bars-components
Note that the OD is more important than the wall thickness, as the stiffness goes up with the diameter to the fourth power. To get the overall stiffness, you take the OD calculation and subtract the ID calculation. Since that fourth power is in the mix, the OD makes a much bigger difference.
In reply to brandonsmash :
These are the ends im going to use: https://www.ebay.com/itm/134728512743
room is at a premium, but i want to fit these in because they can be adjusted while driving which is a cool gimmick. They are meant to be welded on the end.
In reply to Keith Tanner :
Splined bars are hard to utilize with the ends I intend to use. That is without really fancy tooling.
You only need a blade on one end of the bar. Can you get a splined bar and ends and attach the blade mount to a modified end?
The HAZ will change the yield stress but not the elasticity. If you make the HAZ region extra beefy to account for the loss of yield strength, you can live with the HAZ as it is. The bar itself doesn't *have* to be flexible if the blades are doing all the springing, just make sure to be doing the stress calcs to make sure all your parts are well within their elastic regions.
A month late but I plan to replace my heavy home made torch bent 7/8" bar with a welded tube and have done all the research. It is doable.
https://sjsutst.polsl.pl/archives/2022/vol116/257_SJSUTST116_2022_Wheatley_Zaeimi.pdf
I've made quite a few bars, mostly from cold-rolled steel, cold-bent, and two from 1" schedule 40 pipe.
As long as the bar stays in its elasticity, it will work. Since I imagine your car won't have a lot of suspension travel to begin with, you'd be hard-pressed to bend the bar too far anyway.
The thinner the wall thickness you go, the more stress there will be at the weld. Talking out of my butt, I would try to stay 3/16" or thicker, but that's heavy. It may depend on the overall diameter, too. Pick your poison.
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