Tailwheel issues

When I got the  Cub project the tailwheel was missing, so I rebuilt an old 1 1/4 inch Maule SFSA unit I had in stock. It was in pretty good shape but had a little wear on the main bushing, however I did not have the tooling to replace it. Lately I had been experiencing an occasional tailwheel shimmy on landing. Nothing you could not stop with a little forward pressure on the stick but annoying just the same. I thought this was due to the wear in the tailwheel so I ordered a new bushing from Aircraft Spruce and made the tools to do the job correctly. First I had to make a tool to remove the old bushing, my friends at Mid Atlantic Aviation let me use their lathe and I made this tool from some 4130 scrap.

The small end is 0.005 less than the ID of the bushing and the large end is 0.005 less than the ID of the pivot forging. Here is a shot of the new bushing.

Here is the old bushing still installed.

First you have to remove the two screws that hold the unlocking cam and the grease fitting. These extend into the bushing.

Then using the tool in a hydraulic press you can remove the worn bushing.

After cleaning up the forging , I used the tool in the press to install the new bushing.

After installing the bushing I carefully drilled through the threaded holes in the forging and through the new bushing. I then tapped the threads into the bushing. Since installing the bushing slightly reduces it's inside diameter, I reamed the ID to 0.875.

I cleaned and inspected all the other parts and reassembled the tailwheel. The old tire I had been using was worn funny so I installed a new tire.

Here is the completed tailwheel installed on the airplane, notice anything odd?

Notice the pivot axis of the tailwheel. It is actually tilted a little forward when it should be vertical or slightly aft ! This was a real boner on my part because I had installed a 1/8 inch rubber pad between the tailwheel spring and the airplane tail post , this changed the geometry of the spring and changed the pivot axis.

 I removed the pad and no more shimmy. While the tailwheel rebuild was very educational, the wear was probably not the cause of the problem after all. Here it is with the pad removed. I have decided to reinstall the pad and add a couple washers at the front attach bolt to maintain the correct angle. I think the pad does cushion the airframe a little from the tailwheel loads. Here it is all cleaned up , ready for a summer of flying.