So Philbert & Heyduke, I currently only have files and basic file guides for my firewood saws. I'm happy with my results but from time to time i should really get all the angles correctly reset. In your expert humble opinions would I be better of investing in a grinder or a timberline for the 'resetting' task.
A lot depends on your use and preferences.
I have a grinder. I like grinders. But I justified the $300 investment because: 1) I was sharpening a lot of chains for some storm clean up up groups that I volunteer with, which are really hard on chains; and 2) I wanted one (full disclosure).
As the fella that disagrees with me (post above) mentions, you can buy a less expensive, 'clone' grinder for as little as $100, or even a mini-grinder for as little as $30 (
http://www.arboristsite.com/community/threads/hf-chain-grinder-thread.268303/). These can meet your needs for occasional sharpening use, reseting cutter angles, or 'evening out' chains. Some guys will do this to shape the cutters, then follow up with a file to get the edge they prefer.
Before I owned a grinder I purchased the 'pro' model Oregon clamp on file guide (
https://www.oregonproducts.com/pro/products/accessories/BarMountFileGuide.htm). Similar to the Granberg file guides, this can be a tad confusing to set up at first, but once learned, provides extremely consistent, sharp, uniform cutters. Some people use these as their only filing / sharpening method, and some carry these in the field. If you don't mind spending a few minutes filing, this could be a good option for you to consider.
More info in this thread:
http://www.arboristsite.com/community/threads/granberg-file-n-joint-revisited.193630/
Philbert