I don’t believe a “new” sharp chain will be a whole lot of help as a guide Shari. The cutters on a new chain, or even one that’s been sharpened on a chain grinder, will look different than those that have been round filed. It just ain’t possible for flat-sided grinding wheel and a round file to put the same exact contours on the cutters, and if you place your file in one of those “new” cutters I think you’ll see what I’m getting’ at.
Don’t be afraid… ya’ ain’t gonna’ kill the chain. In the absolute worst case you’d have to take the chain to whoever’s been sharpening it, and the grinder will straighten it right out. In my experience, cutters that that see the round file for the first time require a few extra strokes for the file to change the contours (like maybe 6-10), but after that just a few strokes will put the edge back (like 3-4) unless the cutters have been damaged. I like to file the rakers/depth gauges on the first round-filing because they are usually set higher than I like, after that every 5th-6th sharpening seems about right. And about every dozen or so filings I check cutter length with a caliper (a cheap plastic one works fine) before filing the rakers. Keep your file cleared of metal chips between cutters… a file card works best but even a swipe-off with a leather glove will be better than nothing… compressed air will work also.
Your first time results probably won’t be perfect (heck, nothing ever is) but don’t get discouraged… there’s a little bit of a learning curve to it. It ain’t quantum physics… if I (and these other idiots) can learn to file saw chains, I have full confidence that you can. Besides, you need to make a couple mistakes to learn anything, but once you sort’a “catch-on” the process is quite fast. Some common “first time” mistakes are;
- short stroking the file (try to use the full length of the file in one smooth stroke)
- filing some cutters more than others (use the same stroke count on all the cutters)
- ending up with different top plate angles between left & right cutters (learning curve)
- over filing (use just enough strokes to repair the cutting edge(s), no more).
How your chain cuts will give you clues as to where you may have not been perfect.
Such as;
- Small chips/slow cut (didn’t get the cutting edges sharp or rakers need filling)
- Chain/bar get hot (didn’t get the cutting edges sharp)
- Saw cuts at an angle or curve (difference between left and right cutters, could be top plate angle, cutter length, sharpness, etc.)
- Bar binds in the cut (same problem as above, but worse)
- Saw cuts rough, excessive vibration (again, difference in cutters, but not necessarily left to right).
Once you “get-it”, you’ll “love-it”. I find a correctly filed chain will be sharper and stay sharp longer than a chain sharpened on any grinder. Once you “get-it”, you can also experiment a bit with the angles and find what you like best… I sharpen my semi-chisel chains at a slightly different angle than my full-chisel chains because they’re used for different types of wood. It’s been over 20-years since any of my chains have seen a grinder. Even a “rocked” chain gets filled, I just pull the stool up to the bench and spend a bit of “alone time” with it.