I picked up a black Bronco not long ago. Dropped a S-D Hot Rails pickup in it and the sound was OK, but since it's such a good base for mods I tried a '53 reissue SCPB pickup in it.
The SCPB actually fits pretty well as far as pickguard and the recess in the body - plenty of room under there, although I need to erlieve it just a bit on one side. A bit of Dremel work relieving the pickguard let me work it through. But that SCPB pickup seems pretty sensitive to string position, and the G and strings are located well inside the poles...the alignment is bad. I figure that usually alignment with the poles isn't critical, but it seems to be a factor with this pickup, especially on the E.
So I had a bright idea....get a set of 4 threaded saddles, drill and tap the 2-saddle bridge to allow mounting 4 saddles, and use the threads on those saddles to manually position the G and E strings farther out and more in line with the pickup poles.
Got the saddles from Guitar Parts Resource and figured out placements (with the threads to align the strings as needed, it ain't rocket surgery) but ran into a snag....the screws for the saddles are an unusual thread that doesn't match any metric or SAE taps I have. I spent a couple of hours running between hardware stores and couldn't match the threads. Best I can figure they're a 6-40 screw, and although I found a few 4-40 screws and plenty of 6-32 screws, I couldn't find a hardware store with a 6-40 to test them against....much less a tap, although they're available for a couple of bucks online. I'd feel better about ordering a tap if I could confirm what the threads actually are.
Hmmmm.
Maybe the best alternatives are either to get a Musicmaster bridge from Guitar Parts Resource ($20 + shipping), and see if the threaded saddles will mount on it - or to grab a file and just make notches in the stock Bronco saddles a bit farther out...improving the alignment of string and pole piece. But there's not much room for another notch farther out on the saddle unless I make a notch just about over where the set screw is located.