I have a old (guessing ~2005) Jamis Aurora road bike. Recently, I found that the threads on the headset (probably original, nuts are made of aluminum) were stripped. The bike has a steel fork, and is designed for a 1" threaded headset. Apparently these are not very common any more.
A local bike shop had an old one in stock, which looks pretty close to this: http://www.amazon.com/Threaded-Fixie-Track-Road-Headset/dp/B00811SI5E/ref=sr_1_9?ie=UTF8&qid=1431293092&sr=8-9&keywords=bike+headset
Unfortunately, it turns out that due to the length of my fork (or my frame?), I need a "low profile" headset, rather than a standard one. So far, it looks like it will cost around $50 for one of these.
I think the other option would be to replace the fork, which is more expensive, but would save me the trouble of dealing with this problem next time the headset goes.
Are there any other options?