Had a conversation today with Radmores about the Timberline and my current issue of rock hard big overstood Hazel blunting my chains. It seems three times as hard as oak.
They strongly recommend the Timberline, they've sold loads including to professionals and have had very good reports back, apparently they do a far better job than a hand file and get the edge chain back to 'factory sharpness'. Little and often keeps the chain pin sharp.
Think I'll need one as my thick tough-as -iron Hazel is really taking it out of my chain. Its so hard it rapidly blunts the chain, which then gets very hot and consequently slack. Their advice was to use a thin oil such as a cheap car engine oil, which will flow far quicker than the sticky chain oil, and help cool the chain. When I pointed out the lack of eco-soundness to that approach, they said 'or just use neat rapeseed'. Its also thin.
Apparently a heated slack chain is hard to get an edge on as it might have lost the tempering from the overheating. They suggested I might have to chuck it and get another, and another, and another. (£ £ ka-chink).