So while I was descaling my La Pavoni yesterday, I noticed that about half of the bottom lip of the boiler cap (which makes contact with the top of the boiler) fractured and fell off on the counter... hmm: the joys of 40 year old espresso machines
To remedy this, I used the lathe to turn the rest of the lip off. I then shaped it with a carbide cutting bit and added a bit of a chamfer to help blend it. After that, used a file and some sand paper to smooth everything down a bit further. A little blue magic metal polish finished everything off.
Here's the boiler cap after turning it down on the lathe and polishing it
And here is the cap in use and on the La Pavoni
I don't think it turned out half bad. Exposing the brass and peeling away the lower edge of the cap not only added a nice decorative accent, but I think it also improved functionality and reduced the risk of further fracturing of the boiler cap material.