Thanks to Blake and Vince at Flyboy Accessories. I talked them into making the option to have a tailwheel socket with a smaller inside diameter so the original RV-3/4 small diameter taper springs could be modified to a full swivel Screaming Eagle tailwheel. That was about 18 months ago and I just now got around to adding the modification to my RV-3B.
The smaller ID of the socket is 33/64" yielding a thicker wall thickness of the socket as it is the same OD as the standard one. This requires machining a 2" area off of the spring to a constant 33/64" diameter to fit the socket. Flyboy also has a similar modification for the RV-4 that utilizes the standard socket as the RV-4 spring has a larger OD.
Here is a side-by-side comparison of the new small socket optioned Screaming Eagle socket on the left (my RV-3B) and the standard ID socket on the right (for an RV-8 conversion we did concurrently using taper pins):
The aluminum block in the background is a jig we made for the RV-8 to match-drill an existing hole in the spring and not pertinent to the RV-3B modifcation.
Here is a picture of my spring in it's original configuration with the tailhook bend in it. The black line shows how the tailhook portion is to be cut off:
I removed the spring from the tail (one AN4 bolt and nut) and then cut off the bent portion:
When chucking the spring into the lathe for machining we were having trouble due to the taper on the spring using a straight chuck. So we jammed some cardboard in the chuck to provide a conforming clamp up. Due to some runout variation It took a little time loosing and tightening the chuck and tapping the spring with a small ball peen hammer until we had minimal runout. Then we could find the center of the cut end for using a tailstock to machine the new constant thickness area (33/64" diameter). Here is what the cardboard-stuffed chuck looked like. This photo was after machining was done:
Here's an action shot of polishing after cutting:
The replacement Screaming Eagle socket was piloted per instructions and fit to the spring while it was temporarily re-installed on the aircraft so the assembly was parallel to the lateral axis of the aircraft (across the canopy rails).
Following Flyboy's instructions the socket was drilled up and fitted. I re-painted the tailwheel spring with black Imron while it was out of the aircraft.
Here is the final result (prior to chains and springs):
The aircraft handles better and it was surreal to be able to push it backwards while on the ground. The tailwheel doesn't catch on hangar rails or cables like the original "tailhook" type did. Very nice modification.