• Beware of Counterfeit Woodturning Tools (click here for details)
  • Johnathan Silwones is starting a new AAW chapter, Southern Alleghenies Woodturners, in Johnstown, PA. (click here for details)
  • Congratulations to Paul May for "Checkerboard (ver 3.0)" being selected as Turning of the Week for March 25, 2024 (click here for details)
  • Welcome new registering member. Your username must be your real First and Last name (for example: John Doe). "Screen names" and "handles" are not allowed and your registration will be deleted if you don't use your real name. Also, do not use all caps nor all lower case.

Stubby 750 or Robust , American Beauty

Bill Boehme

Administrator
Staff member
Beta Tester
TOTW Team
Joined
Jan 27, 2005
Messages
12,884
Likes
5,168
Location
Dalworthington Gardens, TX
Website
pbase.com
... Friction is what drive a belt pulley assembly even if too much friction becomes negative.

Friction results in a lot of things -- all of which subtract from the available power at the spindle, but driving the belt pulley assembly is not what friction does. It is a necessary ingredient and any drive transmission whether belt, gear, or fluid has parasitic and induced frictional losses. A well designed system reduces friction to a minimum.

In your sketch, the closer spaced pulleys is always a more desirable condition than the ones spaced further apart. The power transfer is essentially the same in both cases, but the longer belt requires greater tension (which is bad because it shortens belt life) to avoid greater slippage than the shorter belt. Flutter and whipping is also a problem in longer belts that increases belt wear. Idler pulleys can be used to reduce those problems, but they bring along their own set of problems of increased friction and belt wear.
 
Joined
Apr 25, 2004
Messages
2,557
Likes
25
Location
Annandale, New Jersey
Friction results in a lot of things -- all of which subtract from the available power at the spindle, but driving the belt pulley assembly is not what friction does. It is a necessary ingredient and any drive transmission whether belt, gear, or fluid has parasitic and induced frictional losses. A well designed system reduces friction to a minimum.

In your sketch, the closer spaced pulleys is always a more desirable condition than the ones spaced further apart. The power transfer is essentially the same in both cases, but the longer belt requires greater tension (which is bad because it shortens belt life) to avoid greater slippage than the shorter belt. Flutter and whipping is also a problem in longer belts that increases belt wear. Idler pulleys can be used to reduce those problems, but they bring along their own set of problems of increased friction and belt wear.

Even I can understand that.
 
Back
Top