Re: Whip finisher destroying my thread.
If you're referring to the UTC type 70 thread, then yes - I had similar issues with my old "bent wire" whip finisher. I think that thin wire/hook style has more of a tendency to catch and nick the thread, and that's all it takes. I love that thread, but one fray while whip finishing and it's game over. I upgraded to the Metz rotating type finisher with heavier wire and the problem disappeared.
Also, when buying your thread spools, take a close look to make sure they haven't been boogered up on the shelf by people running their fingernails across it. Be careful that you don't scrap the face of the spool with your bobbin when putting it in either. That will also fray the threads.
One last thing to watch for is the thread catching on the open portion of the hook eye. That area will catch and separate UTC 70 thread too.
"We fish for pleasure; I for mine, you for yours." -James Leisenring