What glue do you use for the tip? And do you prep the tip prior to install with a thin layer of glue? Glues also have a limited lifespan, especially when opened and kept in room temperatures. Always use fresh glue if you have issues with installs at any time.
I had similiar issues in the past on my first tip installs untill I fine tuned my install process a bit.
First of all, the tip has to be totally flat, I use p400 sandpaper to roughen the surface and sand it flat. Test fit on the ferrule to see that it doesnt pivot on the surface but sits on it flat and square. Then make sure the surface is free of any sanding dust. I like to use compressed air these days but blowing on the tip works aswell. Then I use a drop of Loctite 401 to prep the tip, a drop of glue on the glue side and use a rubber glove to distribute the glue evenly and wipe off all excess glue. Let harden for a minute or so, then wipe gently on the sandpaper to make sure the surface is flat and free of imperfections. When the tip is prepped and ready for install wipe the ferrules face clean with a paper towel. Apply a single drop of 401 on the tip and press it firmly on the ferrule untill it fixes on a little. I like to apply a little pressure on the tip while it dries. On a lathe you can use a drill bit or something similiar to keep things in place while the glue sets. I made a special tool for this from a bolt and an old tip I had cut off a shaft. Let it dry for 5 minutes for the glue to harden thoroughly.
Once the tip is installed I like to use a very sharp carbide cutting bit to cut it down to correct diameter. Cut the shape with a rest and a razor blade as usual, burnish sides gently and wipe the face of the tip with coarsed sandpaper for a scuff and you should have a pretty well installed tip :smile:
I haven't had a single bad install using the above process so far and dont expect to have one any time soon. Let us know what went wrong once you get it right