## Amazing Facts About Pro Saws

OK, maybe we are a little "taken" with pro saws. The good thing is, if you are reading this, you are, too! Yes, we invested more time here than we should have, but next time you're in the crew bus, you'll look really smart.

Q: Do you know how many times a piston makes a trip up or down
the cylinder every second on a pro saw running at 10,000 RPM?

A: 330 times per second.

Solution: On each crankshaft revolution the piston goes up once and down once. The math looks like this: (10,000 x 2)/60 .

Q: Do you know how fast the piston rings travel in
the cylinder of a Husky 394
running at 10,000 RPM?

A: 2,500 surface feet per minute or about 42 feet per second.

Solution: The stroke of a Husky 394 is 1.5", so the math is: (1.5" x 20,000) / 12. To figure what this is in a second, divide your answer by 60.

What's equally amazing is the piston reverses direction 330 times each second. So it actually travels the fastest in the middle of the stroke and slows to a stop at the top and bottom of each stroke.

Q: Do you know how fast the chain glides across the surface of
the bar rails on a bar fitted to the Husky 394 above? Assume the saw is
running a 3/8" X 8 tooth sprocket.

A: 4,890 surface feet per minute or about 82 feet per second

Solution: A 3/8 x 8 sprocket moves 5.87" per
revolution. 5.87" x 10,000 / 12.

A mile is 5280 ft so the chain moves almost a mile in a minute in
"surface feet".

Q: Do you know how fast this is in miles per hour?

A: 55 miles per hour.

Solution: 4890' x 60 / 5280. 5280 ft. is the number of feet in a mile.

Q: Do you know how many times a 32" chain goes around the bar
in one second on the saw above?

A: Over 12 times.

Solution: There are 16.36 links of 3/8 chain in one foot. 16.36 x 81.52 /105. 81.52 comes from dividing 4890 surface feet by 60 seconds.

Q: Do you know how far a chain travels in an average day?
Assume a 6 hr day with the saw cutting 25% of the
time.

A: 83 miles.

Solution: 4891 x 90 / 5280. 90 is minutes is equal to 1.5 hours of continuous cutting, 5280 is the number of feet in a mile).

Q: Do you know haw many times the drive links impact the drive
sprocket in a second?

A: 1330 times.

Solution: 12.7 x 105. 12.7 comes from the
amount of times a
chain travels around the bar in one second.

Q: Do you know how many times the sprocket tip teeth
rotates daily? Hint: the nose sprocket has eleven teeth.

A: 654,682 times.

Solution: This assumes a 6 hr day with the saw cutting 25% of the time. 4891 x 90 x 16.36 /11. Lubrication is important.

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