I assume that you mean depth gages when you say "flats". As you know,
the cutters on the chain are angled up, so each time you sharpen the
cutters, they end up a tiny bit lower than they were before. The
non-cutting link between each cutter is there to keep the cutter from
biting deeper than the saw can handle. Each chain size,style has a
recommended depth for the depth gages to be below the cutting teeth.
It's gonna be somewhere between about 20 and 35 thousanths of an
inch. When needed, I file the teeth with a double cut (real fine) flat
file. There are gages for this distance. You should buy one from a
place that sells lots of chain saws so they will know what you are
talking about when you ask for one.
If I don't have a depth gage, I simply find the flatest part of the
chain's bar and lay a flat piece of anything on top of two adjacent
cutters. I look (or measure with an appropriate feeler gage) to see
how far the depth gage is below the flat piece. if the depth gages
need filing down. Try this in a few spots on the chain and you'll see
how much you need to take off. I then file one or two depth gages to
see how many file strokes it will take and file the rest the same amount.
I think that the competitive guys probably run the depth gages a lot
lower than most of us do. They get bigger chips that way but have to
have a real light touch on the saw to keep it from slowing down/ stalling.

Note that the "flats" on the depth gages shouldn't be flat. You should
round off their leading edges.

Having said all that:
The only time my chains get power-sharpened is when I take the saw in
for service. In the woods I hit the cutters with 4 file strokes each
whenever I start to see that I'm getting a little "dust" instead of
"noodles" coming out of the cut. Then, about every third cutter
sharpening I do the depth gages, or if I feel that the saw is requiring
me to push it into the wood.

Heated with wood for 25 years, made maple syrup with wood for 10,
Pete Stanaitis
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TomNie wrote:

Hey guys,
I got the HF chainsaw grinder that Mac recommended - still haven't used it,
but I got it :-) (and I got a 30 ton logsplitter yesterday).

Question: How are you grinding the flats?

I recently saw a Dremel with proprietary attachment but I don't have a
Dremel. I do have a Foredom carving kit.

I got a fantastic chain info site from an earlier post and I'm sure this
has been covered before so be patient. My computer crashed two weeks ago and
I lost everything (please, that's another story).

TomNie