How to repair a Mallory inductuner (Dumont RA-103, and clones) with a broken shaft

[Kevin Kuehn]

An alternative to JB Weld would be a high quality epoxy mixed with milled fiberglass. You can purchase bulk milled fiberglass, or you can simply take a piece of lightweight fiberglass cloth and cut your own short shavings which can be mixed with the epoxy. Combined it ends up being a white creamy color.

However, a potential long term problem with any adhesive, is getting the area clean enough to create a proper bond. And unless it's a porous material, which the adhesive can penetrate, it's about impossible to get a permanent bond.

[EdKozk2]

I came across this old thread, which I never read until after I repaired a broken ceramic shaft inductuner. I picked up a Crosley 9-407 at the 2018 ETF auction. The tuner was missing the three coil ceramic shaft. I just happened to have a stripped down Dumont RA-103 chassis Tom Carlson gave me in 2017. Luckily the broken coil shaft and parts were still in the tuner.
I used a solid 0.312 fiberglass rod. I cut it from a driveway reflector,that I bought at the local hardware store. Just under 6 inches is all that was needed.
If anyone wants to replace a broken ceramic shaft in an inductuner , pay close attention to the direction and placement of the coils. The front two coils go one direction, and the rear RF coil is going/ wound opposite. I also had to drill a pin hole where the fiberglass shaft slides into tuner shaft. The old broken ceramic shaft had to be drilled out using a masonary bit. I assembled all the coils and shaft with the tuning control turned fully CW to the end of its' rotation. After I got everything back in place I glued the coils to the shaft. If you do use glue make sure to keep it off the metal contact rings/ washers at the end of the coils. I didn't have to make any adjustments to the tuner when I was done. The FM and TV signals came in fine.
Ed