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6061 VS 7075

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Aukai

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#1
I would like to make solid bushings for my car's rear suspension. Rubber insulated bushings do not transfer motion quick enough, so a solid aluminum bushing on a spherical end will be better. Now which aluminum would be preferred, the spherical end is 3/4" ID with a through hole for the bolt of 1/2"ID double shear. For a drag racing application. Thank you...
 
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mikey

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Now which aluminum would be preferred, the spherical end is 3/4" ID with a through hole for the bolt of 1/2"ID double shear. For a drag racing application. Thank you...
Not sure what this part looks like - spherical end?

The advantage of 7075 is a high strength to weight ratio vs 6061. 7075 has almost twice the tensile strength of 6061, machines and performs like mild steel but you can't weld it and it is more susceptible to corrosion. I would imagine a suspension bushing would need to be pretty strong and I would opt for 7075.
 

SamI

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#3
Given that the existing bushings are rubber I can’t imagine the tensile strength of the aluminium would come into play at all here (although I could of course be horribly wrong – without knowing the application it is impossible to say). I would be more concerned with the aluminium galling. What are they being pressed into? You may be better off with a two part bushing assembly where a bushing is made from a low friction material such as nylon and pressed into the housing and an aluminium shaft turns within the bushing.
 

Aukai

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#4
Spherical rod ends, aka heim joints. for a Chevelle with triangulated 4 link suspension. It takes away the softness of the chassis reaction.

 

Manderioli

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#5
Why not use polyurethane bushings like most suspension packages for muscle cars?

Easy to machine, easy to replace.
 

P. Waller

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#6
Titanium is the only answer.
 

9t8z28

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#7
I am glad I found this thread and a fellow Muscle Car owner who’s also a part of HM! I too have a Chevelle. Its a 69 SS396. What year is yours?
I have UMI Performance’s “Ultimate Arms” upper control arms. They are an an adjustable arm with the heim joint like you posted a pic of. I also have a hard poly bushings. Prior to the install of the upper arms I just had SouthSide Machine lift bars. It definnitly helped tighten up the rear end and eliminated my wheel hop issue. A few years later I installed the UMI uppers and it was like night and day difference. I think a little too stiff for my taste but it really helped straighten out the car when launching hard.
I think I am confused as to what part you are looking to make from aluminum ? The spacers on either side of the joint are steel. If this is the part you are considereing making from aluminum I would advise against it. The torque applied to the bolt and nut is pretty high, I couldnt tell you how much but its a lot. Also the amount of stress the uppers see would tear the aluminum up pretty quick. Theres a lot of flex in these frames. Do you have the braces that tie the upper to lower control arm mounts?
Brandon
 

Aukai

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#8
Thank you for the responses, poly would still have some give to it, body mounts, and rear suspension are aluminum bushings. I'm thinking 6061 for price from the vendor, but maybe 7075 would be better if I made my own replacements. These are maintenance items like the heim ends that will need to be checked, and replaced periodically. the front bushings are delrin/delalum. This is for a 1970 Chevelle with a fabricated 9", and adjustable mounting points. Big block with a clutch, and 5 speed. I'll have to look into Ti, would it wear well?
 

mikey

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Aukai

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#10
LOL, I have CRN coated 2.350 Ti intake valves, I know why they work. Thought it may have been an option. Hook, line, and sinker:oops:
 

9t8z28

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#11
Are you reasons for aluminum to save weight?
You said the front bushings are delrin. Which bushings are you referring to?
Thank you for the responses, poly would still have some give to it, body mounts, and rear suspension are aluminum bushings. I'm thinking 6061 for price from the vendor, but maybe 7075 would be better if I made my own replacements. These are maintenance items like the heim ends that will need to be checked, and replaced periodically. the front bushings are delrin/delalum. This is for a 1970 Chevelle with a fabricated 9", and adjustable mounting points. Big block with a clutch, and 5 speed. I'll have to look into Ti, would it wear well?
 

Aukai

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#12
The back bushings are for no deflection, not weight savings. The front bushings are in the upper, and lower "A" arms for smoother operation. The back will be absorbing the load of transferring power/forward motion to the chassis.
 

Mitch Alsup

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#13
Spherical rod ends, aka heim joints. for a Chevelle with triangulated 4 link suspension. It takes away the softness of the chassis reaction.

I would suggest, if you want instantaneous transfer of forces, that the mounting needs to be in double shear.
 

P. Waller

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#14
If you are looking for wear resistance there are steels made just for this purpose.
A7 is an excellent choice for wear resistant tools and parts.

Have it hard chromed after grinding and it will not rust and look good as well.
 

Aukai

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#15
Mitch there is a 1/2" bolt going through to the back side of the cross member for that picture. Mr. Waller the bushings in the back will probably outlast the heim ends, which are a maintenance item that have to be watched with this setup. Thank you....
 

Mitch Alsup

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#16
Mitch there is a 1/2" bolt going through to the back side of the cross member for that picture.
In double shear, the bracket will take 2x as much force without breaking/bending, and the bolt running through it is 8x stiffer! All for the low low cost of.........

{This is right out of "Tune to Win" Carroll Smith (RIP)}
 
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