# What aluminum for bushings?



## Aukai (Oct 4, 2017)

The car I'm working on has replaced the OEM suspension control arms with chrome moly tubing that has heim joints. There are aluminum bushings for reducing, as well as spacing. What type of aluminum is used for the bushings? I have 2024-T351, not sure if it would be the right type for the job though. Thank you


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## mikey (Oct 4, 2017)

No idea what "they" use for those bushings and spacers. I would use 7075 myself, probably T6 as it is easier to get. I have not used T651 but that would have slightly better corrosion resistance. 7075 is very light, good tensile strength and machines fairly well. I would consider this application a structural part and would go with 7075-T651 over something like 6061. 

Here is an ebay listing to consider: http://www.ebay.com/itm/7075-T651-A...483322?hash=item2eb83cbaba:g:v2AAAOSw57xZ0uAw
Under $17.00 for 1-1/4" X 12", shipped.


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## Aukai (Oct 4, 2017)

mikey said:


> No idea what "they" use for those bushings and spacers. I would use 7075 myself, probably T6 as it is easier to get. I have not used T651 but that would have slightly better corrosion resistance. 7075 is very light, good tensile strength and machines fairly well. I would consider this application a structural part and would go with 7075-T651 over something like 6061.
> 
> Here is an ebay listing to consider: http://www.ebay.com/itm/7075-T651-A...483322?hash=item2eb83cbaba:g:v2AAAOSw57xZ0uAw
> Under $17.00 for 1-1/4" X 12", shipped.


Ok great, it will see street time, so being able to monitor, and replace as needed is good. Thank you


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## ddickey (Oct 4, 2017)

2024 is right up there with 7075.
http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=ma2024t4
http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA7075T6


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## Aukai (Oct 4, 2017)

ddickey said:


> 2024 is right up there with 7075.
> http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=ma2024t4
> http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA7075T6


Thank you for the link, pretty close comparison.


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## RandyM (Oct 4, 2017)

ddickey said:


> 2024 is right up there with 7075.
> http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=ma2024t4
> http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA7075T6



Yup, 2024 is a good choice.


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## Bob Korves (Oct 4, 2017)

2024 is very common for aircraft parts.


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## Aukai (Oct 4, 2017)

Bob Korves said:


> 2024 is very common for aircraft parts.


Thank you, I have 3' of 2024, and 2' of 7075. From the above link the 7075 seems to have "harder" properties just looking at some of the numbers. Learning all of this could be another life long career.


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## RandyWilson (Oct 4, 2017)

I would not worry too much about the hardness, pick one that you can machine easily. The axial loads will be limited by the tear-out of the ball (nylon inserts?) and radial by the center bolt.  The only concern would be something hard enough to not hammer out in the reducing shank section.  Electrical tape is right out. But I have been known to make the spacers from Delrin with no issues. Admittedly, it was a 1400# car, but the plastic worked fine.


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## Bob Korves (Oct 4, 2017)

I would be paying attention to the corrosion resistance of the metals, all of those alloys are hard enough for spacers.  The aluminum to steel interfaces can cause corrosion problems.  If the aluminum parts are actually taking the shear and bending loading, then strength would be the issue, but it does not look like the aluminum is taking shear or bending loading, but rather simple spacers/bushings.


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## rwm (Oct 4, 2017)

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


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## Aukai (Oct 4, 2017)

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


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## 4GSR (Oct 4, 2017)

Make the parts out of 1018 steel and have them zinc-nickel plated and you won't be able to tell the difference between it and aluminum!  And it's virtually corrosion Resistance.

https://www.pcimag.com/articles/95782-cadmium-plating-alternatives


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## crazypj (Oct 4, 2017)

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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## Aukai (Oct 4, 2017)

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'?


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.


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## RandyWilson (Oct 5, 2017)

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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## Bob Korves (Oct 5, 2017)

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.


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/


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## RandyWilson (Oct 5, 2017)

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.


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## crazypj (Oct 5, 2017)

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' )
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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## ezduzit (Oct 5, 2017)

Aluminum is a lousy choice for these bushings. I'd use stainless steel.


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## Bob Korves (Oct 5, 2017)

RandyWilson said:


> 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.


Threads bearing a load on the inside of a bushing is always a bad idea, shear and double shear applications should have the full fastener diameter (not threads) working in the shear area.  Grade 8 has nothing to do with it, that would just be a poor design.  I thought perhaps you were spreading the old wives tale that grade 8 bolts are "brittle," which they are not...


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## crazypj (Oct 5, 2017)

Stainless isn't always the best choice.  I wouldn't use the alloy for bushing, just for spacers either side. The reason for upgrading a car with tthat type of bearing is to improve handling/'racing' Even though it's only going to save a few ounces total, every little helps


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## RandyWilson (Oct 5, 2017)

All I said was off the shelf grade 8 are designed to be loaded in tension.  This is all about thread length vs shank length; nothing to do with brittleness. All I'll say about brittleness is the entire SAE rating system is garbage.  If we judged milling machines like the SAE rates bolts, we would be discussing maximum spindle RPM only.


 What the OP is doing here is nothing new or unusual. Adapting rod ends to suspension components has been a favorite passtime of all racers and wannabes since the days of McNamara when "cost-plus" DoD contracts flooded the surplus market with cheap rod ends and aircraft hoses. What he wants to do will work just fine as long as the material is stronger than stale peanut butter.


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## Aukai (Oct 5, 2017)

Very interesting reading, the threads will be outside of the bushing, and brackets. The application is straight line acceleration, with street driving. 1/2" holes are used for the brackets as there are multiple mounting holes in each bracket to move the bars to set different geometries for instant center, and anti squat. Bigger holes less/coarser adjustments.


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