Justin's Project: Making front control arms for my 2005 Acura RSX Type S

MODERATOR’S NOTE: This was originally shared in the Dallas Makerspace Show and Tell - April 2017 thread; but, is a great example of using the tools available at the 'Space and how members come together to help each other by sharing information, expertise, and experience to help each other with projects and so much more that I wanted to pull the discussion out so it can have a life of it’s own. I’m putting the new thread in the #machine-shop category; but, it would also fit very well in the #interest-groups:projects category. @jhrbacek - if you would like it moved to the #interest-groups:projects category, just let @Team_Moderators know! :smiley:


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But it is very an affirmation of Makerism. Now that you’ve made those, there is probably a lot about design, tooling and fabrication. Future builds will incorporate that knowledge/skill set … plus you have pride of craftsmanship. Get with some of the engineering types and see where you can safely remove some weight form the existing configuration. They live for this stuff, they get to apply their knowledge to something other than a dry class paper. Of course it is your car at risk!

Looks good. I’d say that you played it safe. You could have engineered to take more material out but without knowing the forces that would be applied makes it more difficult to calculate.

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I think this is also a testament to the skill of automotive engineers today. They have to walk the lines between “good enough”, “cheap enough”, and “easy to manufacture”. Billet milled control arms are AWESOME!, but there’s a reason Honda (and virtually every other OEM) makes theirs out of sheet metal.
I think (for what little this is worth) if you want to go for lightweight, you’re going to need to go tubular.
Time to learn to weld (or practice, if you already know)! :slight_smile:

I think, it’s a mark of an enthusiast when every project you do is “never quite right”. It’s the mark of an engineer that it’s “good enough for the job”. Nothing wrong with being an enthusiast, even if you are an engineer.
Did I mention what an awesome project and result you’ve showcased? I’ll say it again: EXCELLENT WORK!

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Yes, you are right. If I were to do another version it would be made of steel tubing but with the same geometry for the mounting locations and ball joint socket. I don’t know how to weld yet. I am thinking I would use my machining skills to machine a doweled jig to lay the parts out in the proper positioning for welding. I am not sure it is worth the effort at this point though. It is not a product worth marketing because I know of only about 3 people in the country that are attempting to race this particular type of car in the style of racing. It was truly done out of passion with no expense spared.

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Yes I did play it safe, and using Solidworks Simulation I took out as much material as I was comfortable removing. Unfortunately the material in the middle of the billets doesn’t provide much torsional rigidity but can’t be extracted. Looking at the stock control arm it is basically made of a hollow shell of sheet metal. If I got clever with the PlasmaCAM I could have cut many 2D steel parts out to form a shell and welded them together at the seams to get a design with a similar strength/weight and stiffness/weight as the original design.

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