Pro: Achieves uniform sharpness with little effort
Con: Costs $5 per chain (at your sharpener guy)
Con: Grinds all teeth to the dimensions of the smallest tooth--unnecessary
Con: Heats each tooth to the point of discoloration and losing temper--chips more easily
Con: Sharpener guy says "I'll get the rakers (depth gauges) every 2nd or 3rd sharpening"
Con: Must develop smooth, consistent stroke (guides help here)
Con: Rakers/depth gauges must be addressed with separate file and guide
Clamp-on Filing Jig:
Pro: Very consistent stroke--good uniformity
Con: Fiddle factor for clamping on jig
Con: Must address rakers/depth gauges with separate file and guide
Con: Must develop consistent stroke--alignment guides help
Pro: Maintains proper depth gauge WITH EVERY SHARPENING!
It's this last point that was the kicker for us! The Pferd Chainsharps keep the depth gauge at the perfect height for the amount of wear on the cutter tooth. That way the size of the chip is always "just right".
I find that, barring any other problems with a dull tooth, it takes about 10 strokes per tooth on the first sharpening or so. Then, once the chain is "trained", it only takes about 5 strokes per tooth to dress them up.
Well-worn chains have four attributes--two good and two (potentially) bad. First, a well-worn chain has been through enough heating and cooling cycles that it won't stretch much anymore. That means fewer adjustments for chain tension. Next, you'll notice that a well-worn chain cuts WELL! The distance between the raker and the top cutter is increasing and the depth gauge is having less effect. As a result, the tooth cuts lots of wood all the time. You'll seem to rip through logs. One downside to a well-worn chain also stems from this increasing gap between the raker and the top cutter. You'll notice much more kickback and chatter when trying to bore cut. Kickback is dangerous! So, if it's annoying, throw away your old chain and put on a new one. Also, as your chain becomes well-worn, the cutter tooth becomes very small and may break-off or chip. That would be one signal it's time to put on a new chain.
Round files: I get about 7-8 sharpenings when I'm "training" or "breaking-in" a new chain. This means 10 to 12 strokes per tooth. Once I have a trained chain, I get 10 or more sharpenings out of the round files because I'm only doing about 5 strokes per tooth to dress them up. Above all, I don't hesitate to pull a worn set of round files (and send them to the metal recycling bin). At about a buck apiece, I'm much more productive with fresh round files. A new round file just feels GOOD!
I've noticed a difference between brands of round files. I tend to use 7/32" round files. While I like most Woodsman Pro products, I've noticed that their round files aren't particularly straight (true). Notice the daylight gap that varies while I roll the Woodsman Pro round file in position. These microns of difference surely contribute to a lack of uniformity (of unknown consequence). I've noticed that the Pferd brand round files tend to be more true and straight.
Richwood Timber LLC
richwoodtimberllc (at) w9fz.com