Before we get into the fun part of making the suspension components, we should first look at the SAE design subject which states:
"The vehicle is to be a prototype for a reliable, maintainable, ergonomic, and economic production vehicle which serves a recreational user market, sized at approximately 4000 units per year".
Additionally, teams are scored based on the cost of materials and labor necessary to build the car. Taking these as guidelines, we created a jigging systems that might be used by manufactures but also wanted it to be simple enough to be reproduced with manual machining.
Flat pieces under 1/4" were laser cut and anything larger done with a water jet by M&J Engineering. You may have noticed in the CAD drawings that we do not run the tubing right up to the spherical bearing cups. Although heavier, it reduces the number of copes, makes jigging/welding easier, and is a better option if this vehicle is sold as a weld-it-yourself kit car, which we thought was a fun idea.
The thicker pieces in the background are cut with a waterjet giving them a sandy finish and the pieces in the foreground are laser cut. The machine at M&J automatically accounts for the laser's kerf (cut width) and our 3/8" holes were precise to 0.001" which made the shoulder of the bolt fit too tight. We will have to take this into account for the next batch of laser cut materials.
Here is the piece from the laser cutter.
Suspension arm mounting tabs and gussets. We left some extra material on the gussets to either bend over the tubing or cut off.
The tube end is made easily on a mill and lathe.
Say hello to the Master Jig 9000. It is a steel plate with drilled/tapped holes and customized shaft collars.
Set up with the upper control arm (UCA) in place.
We shaved off 1/16" from the bottom of the shaft collars to give them a nice flat spot.
Then we center drilled, drilled, and counter bored holes so a SHCS would not interfere with the tubing.
Deburring
Drilling and tapping holes for the collars that will hold the upper/lower front control arms and rear swing arm.
Testing it out
Terry making the rods that separate the suspension mounting tabs
We wanted one jig that could be used to hold the lower suspension arm tabs to the chassis and also hold the bushings in place for the lower control arms (LCA) on the Master Jig 9000.Very easy to make on a manual mill.
The 4 holes on the left are for mounting the LCA bushings.
Finally we move on to jigging and welding a few upper control arms.
Arm in place on the jig
Since everything was designed in SolidWorks, knowing what heights to make the jigging pieces was a piece of cake.
We removed the arm from the jig after placing all the tack welds to find it was not setup properly in the jig the first time. See video for explanation.
Not afraid of a little filler material.
The result of precision machining and jigging.
We are definitely not professional welders
Not sure on a color scheme or if we have time to paint the vehicle so these were quickly clear coated and considered done.
And now a lower control arm.
We started out coping the arms on the fish mouth sander but our aged belts kept breaking at the seam.
On to the coping machine we setup on the drill press.
Matt looking really serious
Wrapped sandpaper around another tube and put the finishing touches on the cope.
Kyle Setting up the Jig
Components cleaned and setup on the Master Jig 9000
Urethane bushings
Decent fit
After tacking the arm, we used this solid piece of 1144 medium carbon steel to hold the outside of the bushings.
Kyle stacking dimes
Getting better
Here is the jigging of the trailing arm mount which is welded to the rear roll hoop (RRH).
Setting the RRH to 20°
These parts were laser cut and mounted at 25° outward
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