Engineering Info on Harvester Chain

Harvester Working

Higher chain speeds (with attendant power) usually create faster cutting speeds. At the same time, there is an inverse relationship between faster cutting speed and service life of saw chain, guide bars, and drive sprockets.

Chain Speed Calculation

Chain Speed = Rpm x T x P

The above formula can be used for chain speed calculation where:
Rpm = Motor or drive shaft speed in revolutions per minute
T = Number of teeth on the drive sprocket
P1 = Chain pitch factor for feet per minute (see chart below)
P2 = Chain pitch factor for meters per second (see chart below)

Chain Speed Factor Chart
Chain Pitch OREGON® Chain Type P1 P2
.404" #16H or #18H .067 .00034
3/4" #11H .131 .00066

See the specifications in the Engineering Info for information on what chain speed you should be running your harvester chain.

Cutting Rate Estimation Formula

When running at recommended chain speeds (above), an estimate of soft-wood cutting rate may be calculated according to the formula below: 

Cutting Rate = F x Hp

The above formula can be used for estimating soft wood cutting speed calculations where:
Hp = Horsepower input to chain
F1 = Factor for square inches per second (see the table below)
F2 = Factor for square centimeters per second (see the table below)

Cutting Rate Factor Chart
Chain Pitch OREGON® Chain Type F1 F2
.404" #16H or #18H 3.5 22.6
3/4" #11H 2.8 18.1

The information above is provided courtesy of OREGON® Systems Division of Blount, Inc., from their Mechanical Timber Harvesting Handbook. We urge you to contact OREGON® customer service at (503) 653-8881 for explanation or clarification of information you are unsure of or do not understand.