I got another Viscount, this one is very crusty and I heard that the spindles are known to break. Should I be concerned about it breaking under the pressure of fixed riding? It is for sure a late model from around 1975 if that helps.

I have to ask that you have the Yamaha Tange replacement fork as no one should ever ride the original fork. I have read that the spindle had an inordinate number of failures so you may have issues with a fixie adaptation and hopefully not when you are panic breaking.

I got the bike without a fork and am planning on using a steel fork that I had laying around.

The spindles that used a circlip to hold them in place among the cartridge BBs had a reputation for snapping at that circlip groove. I wouldn’t ride one of those fixed.

It is the kind yoy described. I guess I will just be making it to be a singlespeed not a fixed gear.

It is a red and white Viscount Aerospace from around 1975 with the c clips on the BB spindle

So you want to make sure it will break only when you are pedaling forward?

50% less risk. Hard to get good odds like that with just one decision. 🙃
Anybody want a silver one?

I mean it is more safe when you are NOT relying on the drivetrain for stopping.

Yes, they can fail:

https://pardo.net/bike/pic/fail-001/FAIL-012.html

How common is it? I don't know, but as Clint Eastwood put it, "are you feeling lucky?"

I heard it was because of poor casting processes that caused the spindle to be brittle.