After buying my Squier Mustang and going from stoked, to annoyed with its inability to return to pitch, to utterly contemptuous of Fender's "Dynamic Vibrato" design, I have taken it upon myself to build the vibrato they should have.
Actually, I'll back up. The first thing I did when I got my Mustang was address the silly design of the rocking bridge and make THAT what Fender should have. I guess since the wheel hadn't been invented at the time of the Mustang's development, Leo had to get by with his bridge resting on points in cups hoping that the strings it supports don't push it forward and then possibly returning to whatever position the user initially wrestled it into after each bend.
But now that we have roller bridges... that's what I used. I drilled the bridge post holes for steel sleeves, fixed it in there rigidly, and replaced the barrel saddles with Kahler Flyer saddles from the 80's. These allow for individual height and intonation adjustment and have brass rollers. They're ever so slightly narrower than the stock ones so there's a small amount of clearance between them (very small) but they work pretty well.
Actually, the bridge is going to get reworked but that's not the focus of this post. So moving on, after I strung my Mustang with 12s and moved the springs down to the lower notches on the posts, it took very little time before my vibrato had become worthless at its original task, which is to drop the pitch and then RETURN it. You can see in the pictures how the holes in the plate have been all chewed up. Using those as a pivot is just idiotic. With an original Fender plate and especially with a crap thin Squier plate.
So I decided that I really like the Jazzmaster vibrato and that it should live in my Mustang so I set to reworking things to allow that to happen. I bought a JM assembly, dropped my Mustang off at the Body by Forstner clinic for a few minutes, and cut the necessary slot and screw holes in my stock plate, which is just the prototype. The horse's mule.
Issues that need ironing are that the stock JM vibrato rocker places the vibrato arm right where the Mustang bridge is so either the entire assembly needs to move rearward or the collet mounting hole needs to be redrilled closer to the pivot. I originally planned on a new mounting plate slightly longer than original to accommodate the stock JM layout but now I really like the idea of retaining the stock Mustang shape. It's big enough as-is. So I need to redrill the collet mounting hole about 1/2" back.
Another issue is that the bottom two plate mounting screw holes are not accessible with the JM rocker in place so they will have to be relocated out to the sides. And actually, this relocation just might allow the rocker slot to be pushed far enough back that the collet arm can stay where it is but I'll figure that out once I know this thing can work..
And the last issue is the spring preload screw. I used the stock Mustang center plate mounting screw hole for it but it should be about 1/8"-1/4" closer to the bridge. And my plan to rework the bridge will entail moving the lip that holds the screw heads slightly rearward to allow the 4 reversed saddles to be turned around (the issue is that the reversed ones have contact between roller and spring) so the issue will be compounded. I figure this will be solved with a countersunk flathead screw.
If you're still reading and still interested, stay tuned!