What aluminum for bushings?

I don't believe the strength of the alloy is an issue here as Bob suggests. 2024 with not be very corrosion resistant and will turn gray over time. Personally, I have stopped using it entirely. If this part needs to look good, 6061 or 7075 would be good choices. It is in contact with steel, but I think dissimilar metal corrosion is only a major issue when you throw in water. Ask me how I know...I just had to cut a homemade rack off my truck with an angle grinder because the SS bolts were welded by corrosion to the 6061 parts!
R
 
Thank you for the responses, and insight. These bushings are now hard point fixtures, removing any cushioning/deflection from this part of the suspension. There may be water exposure, but not intentionally, only if caught in the rain. The heim has SS ball, and is considered a maintenance item in this application. The heim is 3/4", and the suspension bolt is 1/2" grade 8. the car weighs in around 3800 lbs, and will be causing a good amount of shock loads. Upper mounts in traction/pulling, lower mounts in compression/pushing. If anyone is bending over far enough to see if the bushings are tarnished, I'll kick em in the butt.LOL
 
Personally I would make a 'shim tube' with 1/8" wall then use alloy spacers on 'outside' If corrosion is likely to be an issue, have them clear or colour anodised.
BTW, did you pay the $400.00 Photobucket extortion 'fee'?
 
crazypj said:
Personally I would make a 'shim tube' with 1/8" wall then use alloy spacers on 'outside' If corrosion is likely to be an issue, have them clear or colour anodised.
BTW, did you pay the $400.00 Photobucket extortion 'fee'?
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I was thinking I could make the bushings out of something more durable, I'll have to practice and see how it goes, but the heim joints still need to be changed, just not sure how often.
When Photobucket was first harassing me there was a 100 dollar option for hosting, but they keep trying to get the 399.00 option with popups. I guess I have a limited amount I can do, but haven't reached it yet. I have a complete car build, plus other stuff on there 2600+ pictures. If I have to bail others will have found better hosting sites by then. I dread having to move everything.
 
As an aside, and I may be preaching to the choir.... Grade 8 bolts are designed to be loaded in tension, not shear. As such, the thread length is way too long for what you are doing. You do not want the threaded section of the bolt in these spacers, or even in the supporting frame bobbins. I preferred to use AN airframe bolts. This is a Navy town so such hardware is readily available (just don't mention metric!). Another option would be to find a Grade x bolt of sufficient grip (shank) length and lop off the excess threads.
 
RandyWilson said:
As an aside, and I may be preaching to the choir.... Grade 8 bolts are designed to be loaded in tension, not shear. As such, the thread length is way too long for what you are doing. You do not want the threaded section of the bolt in these spacers, or even in the supporting frame bobbins. I preferred to use AN airframe bolts. This is a Navy town so such hardware is readily available (just don't mention metric!). Another option would be to find a Grade x bolt of sufficient grip (shank) length and lop off the excess threads.
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Fasteners are rated for loads in both tension and shear. Grade 8 bolts are no exception. Used within their rated yield strength, bolts work. Grade 8 bolts have higher yield strength than grade 5, 150 to 120 ksi.
http://tinelok.com/grade-5-vs-grade-8-fasteners/
 
Bob, this has nothing to do with strength specifications, that's a different ball of wax. This is about thread design, specificly the grip length. Using a standard grade x bolt in this application will result in threads being pressed into the internal bore of both the spacer and the frame bobbin.This application requires a bolt that has a thread length designed to work with a double-shear application.
 
When I was training, we had a marine engineer teaching us. (he had a lot of interesting tales about 6ft diameter cylinders and various ship enge stuff) Anyway, I was concerned about an axle I had made to fit a BSA wheel into a Royal Enfield. He did the math single shear was over 100tons for 5/8" steel I used. As there were multiple shear paths, te rating was way more than anything I could ever do to it (including 'throwing off a cliff' :big grin:)
Also, I feel I'm lucky with only 0.5 gb storage used on Photobucket, still totally sucks they 'they' will only let you download individual pictures and not entire albums. I'll eventually pull everything off there and tell them where to stick their demand
Randy, the standard steel/rubber bushing almost always has serrated ends and bolt threads bearing on frame at one end. The heim joint is much narrower so needs the spacers. I would make them 'cone' shaped to give maximum support on frame but also make singe tube about 0.020" shorter than the outer dimensions of mounting point (so it will still clamp everything together). Drill out mounting holes to 3/4" then use 1/2" bolts to hold everything. It would probably be total overkill strength wise, suitable for much heavier vehicle
 
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Aluminum is a lousy choice for these bushings. I'd use stainless steel.
 
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