Chainsaw Tooth Velocity

Status
Not open for further replies.

MolaKule

Staff member
Messages
21,389
Location
Iowegia - USA
Thread starter
If a chainsaw sprocket of 1.5" Radius is rotating at 4300 rpm, how many feet will any one chain tooth travel in 1 second? Recall that Tangential velocity Vt = w*R, where omega w is the velocity of the sprocket in radians per second and R is radius of the sprocket. Of course, we're going to lube the chain with a tacky 30 grade oil called, "Bar and Chain oil." smile
 
Last edited:
Messages
2,131
Location
Ottumwa, Iowa
35.83repeating?(I forgot the repeating symbol and an to lazy to look it up.) Edit that would be the linear speed though not the tip speed around the sprocket. Edit 2 I did it the dumb way not the formula way. Edit 3 I didn't do it right at all. 3377 ft per second.
 
Last edited:

MolaKule

Staff member
Messages
21,389
Location
Iowegia - USA
Thread starter
The velocity of the chain is approximately equal to the tangential velocity of the sprocket. Hint: First convert RPM to radians/s. So in one second the tooth will have traveled X feet????
 
Messages
4,552
Location
Pittsburgh,PA U.S.A.
4300 RPM/60 seconds per minute = 71.66 revolutions per second. The circumference of a circle = pi X Diameter or pi X 2 X Radius Circumference of a 3 inch diameter circle is 3 X 3.14 = 9.42 inches 71.66 revolutions X 9.42 inches circumference = 675.0372 inches per second. Divide by 12 to get feet per second. 675.0372/12 = 56.2531 feet per second
 

MolaKule

Staff member
Messages
21,389
Location
Iowegia - USA
Thread starter
Originally Posted By: cpayne5
~56.3'?
In what units?
Originally Posted By: A_Harmon
4300 rev/min x 2*pi radians/rev x 1 min/60 sec x 1.5 in x 1 ft/12 in = 56.28 ft/sec, or about 38 mph.
So any one tooth will travel how many feet in one second?
Originally Posted By: JiminPA
675.0372/12 = 56.2531 feet per second
So any one tooth will travel how many feet in one second?
 
Last edited:
Messages
945
Location
Virginia
Originally Posted By: MolaKule
Originally Posted By: cpayne5
~56.3'?
In what units?
Feet, as indicated by the apostrophe (lazy man's prime). smile
 
Messages
4,552
Location
Pittsburgh,PA U.S.A.
Originally Posted By: MolaKule
Originally Posted By: cpayne5
~56.3'?
In what units?
Originally Posted By: A_Harmon
4300 rev/min x 2*pi radians/rev x 1 min/60 sec x 1.5 in x 1 ft/12 in = 56.28 ft/sec, or about 38 mph.
So any one tooth will travel how many feet in one second?
Originally Posted By: JiminPA
675.0372/12 = 56.2531 feet per second
So any one tooth will travel how many feet in one second?
Answer 56.28 Feet per second
 

MolaKule

Staff member
Messages
21,389
Location
Iowegia - USA
Thread starter
Originally Posted By: cpayne5
Originally Posted By: MolaKule
Originally Posted By: cpayne5
~56.3'?
In what units?
Feet, as indicated by the apostrophe (lazy man's prime). smile
Sorry, didn't see the apostrophe, but yes you and Mr. Harmon and Jim were all correct, just trying to get everyone to answer the question of "how many feet of travel in 1 second?" Any one tooth or chain link will travel 56.25 feet in any 1 second if the chain's linear velocity is 56.25 ft./sec. thumbsup
 
Last edited:
Messages
7,903
Location
Michigan
What's the trick here? Are you going to nitpick about how tall the teeth are, which would change the tangential velocity. How long is the bar? What is the radius of the drive sprocket? Am I biting on your hook?
 
Messages
945
Location
Virginia
(2*pi*1.5)x(4300/60) first part is circumference second is revolutions per second full revolutions x circumference = inches traveled per second divide by 12 to get feet
 
Last edited:
Messages
10,000
Location
Waco, TX
Originally Posted By: jhellwig
Edit 3 I didn't do it right at all. 3377 ft per second.
3,300 feet per second is way faster than the speed of sound that's high velocity rifle bullet speed
 

MolaKule

Staff member
Messages
21,389
Location
Iowegia - USA
Thread starter
Originally Posted By: A_Harman
What's the trick here? Are you going to nitpick about how tall the teeth are, which would change the tangential velocity. How long is the bar? What is the radius of the drive sprocket? Am I biting on your hook?
No trick just simple calcs and units conversions to get to: How far will anyone tooth travel in one second? Sprocket radius was given as R = 1.5" and I stated that the tooth velocity (for all practical purposes) is approximately equal to the tangential velocity of the sprocket. Bar length is immaterial. The linear velocity of the chain, which carries the teeth and links, is the key.
 
Last edited:

MolaKule

Staff member
Messages
21,389
Location
Iowegia - USA
Thread starter
A_Harmon and JimPghPA showed the correct calculations so we're going to give each a set of virtual BITOG Piston Cup Cufflinks. thumbsup Mr cpayne5 will receive a virtual BITOG coffee stirrer. thumbsup
 
Last edited:
Status
Not open for further replies.
Top