Here are a few more pics showing a bit more about how I did my quarter ellipticals.
As noted in the thread I linked to, you can't just just the springs in half to make two sets of quarter ellipticals. The arch in more semi-elliptical springs is not uniform and the axle mounting point is usually not centered in the spring...there is more spring toward the rear of the car and less toward the front. So what I did is make two sets of quarters from the fronts of two sets of semi's. I'm then going to use the rear portions of the semi's to make two more sets of quarters that I'll be using on the rear of my new chassis. The point is, don't mix fronts and rears of your semi elliptical springs. That way the arc (and spring rate) will remain the same for both sets.
Once I cut the springs to the length I needed I had to drill two holes for mounting purposes. If you haven't dealt with leaf springs BE PREPARED with some heavy duty drill bits. The tempered steel in leaf springs is very hard and it takes some doing to drill them out. The first picture shows the four leaves for one quarter elliptical cut down to the lengths I will use. The longest is 23 inches.
The second picture is a close up of the holes I drilled. Note that the end hole is a normal 1/2" hole but the front hole is larger and is elongated a bit. This is necessary for two reasons. The end hole holds the springs in alignment length wise while the front hole allows for adjusting each leaf a bit to the left and right so that you can get them lined up perfectly one over the top of the other. The hole is elongated because the spring is arched and when you bolt it down to a sold mounting platform the spring is going to flatten out slightly and thus the holes will move slightly further apart. It is also much easier to line up the springs and get the bolt through all the holes if the holes are elongated. I enlarged the holes by just using a burr.
The third shot shows how I mounted the springs. This is a shot from the underside of the mounting "box". My setup is fairly unique (it utilizes a Ford F-150 Twin I-Beam) so you probably won't be mounting yours in a similar fashion. But this may give you some ideas to work from.
And the last shot is how it all looks mounted on my car. Obviously, I've mounted my in a traverse position (springs perpendicular to the frame) but you could mount the springs parallel with the frame as well if that works better for your particular build.