Broken Zenith 10S690 Flywheel Tuning Shaft

[vortalexfan]

Hello everyone, the other day I was trying to replace the belt on my Zenith 10S690 tuning drive mechanism and when I went to put the new belt on the knurled bakelite shaft broke off of the flywheel assembly where the belt would attach, and I tried gluing it back together but no luck.

Does anyone here have any experience with repairing this issue, or have a way to fix this?

I tried looking on everyone's favorite auction site but nothing came up.

any help with this issue would be appreciated.

See pictures below.

[old_coot88]

The flywheel is clearly a potmetal casting. How far does the shaft extend inside the casting? Does it go past the level of those two bolts? If not, you could maybe use JB Weld to build up the area formally occupied by the broken collar. Keeping the shaft perfectly aligned would be a challenge though.

[vortalexfan]

Originally Posted by old_coot88

The flywheel is clearly a potmetal casting. How far does the shaft extend inside the casting? Does it go past the level of those two bolts? If not, you could maybe use JB Weld to build up the area formally occupied by the broken collar. Keeping the shaft perfectly aligned would be a challenge though.

If you are referring to the brass shaft in the middle of the flywheel assembly, then yes the brass shaft goes through to the other side of the flywheel.

It's a hollow shaft because the shaft that connects to the power switch goes through there.

https://www.jbweld.com/product/steel...xy-putty-stick

Would the JB Weld Product linked to in the link above be a good product to use in this application?

[old_coot88]

I'm not familair with the 'Stik' version of JB Weld. A 'quick setting' product has little time to wick into the microstructure of the joined surfaces, resulting in a poor bond. I've used original (slow setting) JB weld extensively over the years. I mix it about 55% hardener, 45% resin rather than the recommended 50/50 mix. It sets up harder that way.

This guy scientifically tests some other products' performance -
https://www.youtube.com/watch?v=XObmZIbHOzY

[vortalexfan]

A little update, I did manage to fix the flywheel tuning shaft with a rubber grommet slipped over the flywheel shaft and then used an old VCR Square Belt that was the right size to go between the flywheel shaft and the tuning capacitor drive pulley.

See Picture below.