The MS 170 is the saw my brother-in-law gave me in 2019
He upgraded to something bigger, and the 170 sat in my garage for three seasons before I actually started using it. When I finally did — two winters ago, bucking up a red oak that came down in a windstorm — I ran the original factory chain until the cutters had been filed back so far they were level with the depth gauges. That's the end of a chain's honest life. At that point it's a wall decoration, not a saw.
For the replacement I tried the APOROZONA 16" 3/8 LP, .050 gauge, 55 drive links — their AP—16CB—LP. $18 shipped, which put me in the mindset of it being a consumable, but the chain itself feels more considered than the price lets on. The rivets are crowned evenly, the drive links seat cleanly, and the chrome on the cutters shows a consistent depth under a loupe. I am a machine-shop teacher by trade and I will say this: it is built to the same spec as the Oregon it would cross-reference to.
Break-in ran true
First tank, just as the included card said it would, the chain stretched. I re-tensioned after about 45 minutes of cutting and the sag disappeared for the rest of that session. Second tank, no adjustment needed. By the third the chain had settled and the tension held through a full half-cord of seasoned fir without me touching the tensioner.
https://img.manualstool.com/aporozona/tutorials/six-weeks-with-the-16cb-on-my-ms-170/SCENE_01.png
The wood it went through
Over six weeks I ran the 170 and the new chain through:
- About a cord of green doug fir (branches up to 8 inches through)
- A quarter cord of seasoned red oak
- One stump cut into chunks for a neighbor's fire pit
- A half-day of limbing a downed madrona
That is light-duty to medium-duty by the standards of a rural homeowner. I am not doing commercial tree work. I am clearing my own fencelines and splitting my own winter heat. For that job the 170 is adequate and the 16CB has stayed sharp.
Filing it
I sharpen with a round file at the manufacturer's 25° and 30° combination — same as I would on the factory chain. One full touch-up per tank when cutting oak, every other tank on fir. The steel takes a file predictably; no skating, no flex, no chatter. Compared to the last aftermarket chain I tried (a Harbor Freight house brand that shall remain anonymous, but which went dull in a single cord and then would not re-edge properly), the APOROZONA holds its edge through roughly twice the work.
https://img.manualstool.com/aporozona/tutorials/six-weeks-with-the-16cb-on-my-ms-170/SCENE_02.png
What I'd watch
The only real gripe is shipping. A chain loop is small enough that it ships in a padded mailer, but the one I got arrived with a fold across the middle that made the first installation a little stiff. It worked itself out in five minutes, but it's worth straightening a folded chain on a workbench before you put it on the saw.
Otherwise — it cuts straight, holds an edge, doesn't throw the sprocket, and costs less than a restaurant lunch. I'll buy another before winter.
— Paul D., Yamhill County, Oregon