scared of building my own control arms, should I be?

 
Maybe it is the fear of the unknown, but I would like to replace my king pin front suspension on my ’77 Datsun with some ball joints and use a Hard Body spindle, and eliminate the strut rod. I just don’t know where to start.  I can cut and weld, but do not have a way to bend tube. What should I look for? Does anyone have any pics of their control arm jigs? Any advice is appreciated.

i truly admire your gumpshun to go into the unknown. i have often wondered that as well. seeing Seth (twisted minis) and the other guys make magic happen with metal is truly inspiring. i hope you the best. the geometry has always kept me from doin something like this.

I think I do my jigs different than other people. All of the ones I have seen are based off of a plate. I generally build a 2x3 or 1.5x2.5 frame to base mine off of, because I don't want any chances of the jig flexing. I base my designs off of the stock arms to keep geometry the same. On the last set I did for the D50, I made some lower ball joint cups, and a block to hold them in place on the jig.    I use the height of the balljoint mount versus the height of the bushing in order to achieve the angle of the balljoint I want. On the bushing side of the jig, I have some 1.5" round stock with a 3/8" hole drilled through it. It fits snug in my 1.75" .120 wall DOM. Here is the jig.     And a finished set of arms.    I feel like it looks easier than it actually is. I spent about a month straight designing these arms in the end.

Well its good that your scared because your worried about someone other than yourself. Probably worried about something breaking and harming you or another driver. Anyways, control arms always look way easier than they are. There are a lot of pieces that need to be milled or turned and most people don't have or have access to these types of tools. I make everything for my arms, as well as parts for other control arm builders, on manual machines so its very time consuming. I base my jigs on modified control arms and change out parts as needed, unless I am provided a print on how to build them.

Ya Chris makes a lot of the stuff I need. He did the upper balljoint cups seen above. Sometimes I just don't have the time to turn these things down myself. The lower cups I did had to start as solid 3" stock. I'm not a great machinist, so it took me all day to make 2 of them, but I needed them that day.

That is some awesome work. I was thinking about a piece of flat stock with the four holes drilled in it to use a bolt in style ball joint for the uppers. Not sure what to do about the lowers, what makes them triangulated? I saw a cross shaft in a Ford Daytona race car and the cross shaft was horizontal instead of vertical, never seen them done like that.

I've never seen a vertical cross shaft.   Your arms won't be triangulated unless you make them that way. If you do triangulate them, they way you do it is up to you as the fabricator.

I don't think that I was clear on the vertical, the more that I think about that less sense that it makes. The cross shaft was flat, and then the bolts that ran through it to the frame where vertical. I hope that makes better sense.I could see some advantages to this way to help ball joint binding issues.   So on those lower arms, do they bolt up to the stock location on the front cross member? I don't see how they would. I assume that you would use some type of mounting tab, much like a link bar mounting tab that is welded to the frame. Awesome Discussion, I am learning a lot here.

Some Mustang II kits mount the upper arm that way, with the bolts vertical. There are advantages and disadvantages to each.   The center of the arms mounted to the stock location. The other piece I made tabs for to attach to the frame.

--------------------------------------------- Originally posted by KAOSS I don't think that I was clear on the vertical, the more that I think about that less sense that it makes. The cross shaft was flat, and then the bolts that ran through it to the frame where vertical. I hope that makes better sense.I could see some advantages to this way to help ball joint binding issues.   So on those lower arms, do they bolt up to the stock location on the front cross member? I don't see how they would. I assume that you would use some type of mounting tab, much like a link bar mounting tab that is welded to the frame. Awesome Discussion, I am learning a lot here. ---------------------------------------------If you ran the bolts vertically then how do you plan to adjust the camber?