In article 4OC_e.84002$DW1.76538@fed1read06,
"SteveB" wrote:

Only one last question .......... someone said to get the .375" chain, and
this saw comes with .3125", IIRC. Is there any real differences in chain
besides dimensions?

That number is the pitch, or spacing between rivets. Measure across
_three_ rivets, and divide by two. There's a second number that goes
along with the pitch: gauge. It's how wide the drive links are where
they fit the bar groove. Usually one size of pitch has a corresponding
gauge and no others, but you can get chains of thicker or thinner gauges
in the same pitch. .050" is typical for homeowner saws, IIRC. Changing
pitch means changing sprockets, and changing gauge means changing bars.
Keep that in mind when you shop.
You also have different cutter arrangements. Standard has a cutter,
spacer, cutter, spacer around the full length of the chain. Semi-skip
will have one spacer, then two spacers, then one again, with cutters in
between. Skip has two spacers between each cutter. Standard is more
aggressive, full skip is best for really long bars that will need the
most room for chips and you can drive a longer chain with the same
powerhead without bogging down. Semi-skip is pretty common as a
compromise.
"Safety chain" or low-kickback has the exact same sizing system. The
obvious physical difference is that the spacer links have a hump on 'em.
That hump causes pretty lousy cutting performance after you sharpen the
chain a few times.
The cutters themselves are available in various profiles. The oldest
is square ground chisel, which is extremely aggressive. It's also
fickle about sharpening and will go dull in an instant. The new rounded
and semi-chisel profiles are easier to sharpen, hold and edge longer,
and take less horsepower to run. Just have to cut a bit slower.
For fast cutting with a little saw, but reasonable maintenance, .050
gauge, whatever pitch as long as it matches your sprocket, standard or
semi-skip, non low-kickback chain. (assuming you're able to locate some
in that size) If you can choose between 7 or 8 tooth sprocket, get 7.
It lets a little engine keep its revs up.
There are two varieties of sprockets out there. One that looks like
a spur and is called a spur drive, the other looks like a washer with
slots around the edges, called a rim drive sprocket. The second type is
removable from the clutch bell, so it's cheaper if you plan to keep the
saw long enough to wear out a few chains and a sprocket or more. Also
marginally more tolerant of a stretched chain.
Or do it the easy way and just go by trade name. Oregon micro chisel
ripping chain is probably what you'd want. I don't have a cross-ref to
tell you the equivalents from other manufacturers. Sorry.
Disclaimer: The above is based on lots of maintenance experience and
medium-low actual chain sawing experience. Could be biased somewhat.

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