Crank, Forged or cast?

[Rusty McNeil]

Just curious about something.

In the past, on American V8 stuff, I could tell at a glance if the crank was cast or forged simply by looking at the "seam" or mold-die mark, which is the line that runs the length of the crank on the unfinished surface of opposite sides of the crank.

On a cast crank, the seam was just that, a narrow seam, 1/8" or so, indicating where the casting mold halves meet together,
On a forged crank it has the seam as well but it's thicker/wider , maybe 3/8"-1/2" indicating where the metal pushed out past the edges of the two halves of the dies in a hammer forge.

This vmax crank is somewhere in between, and not having eyeballed very many other (read none) motorcycle cranks I don't have any thing to compare it to.....

Is this crank Cast or Forged, and how do we know?

Thanks,

Rusty

 

[alorio1]

Re: Cran, Forged or cast?

Try this Rusty...http://www.youtube.com/watch?v=VxmbGBx0Ybg


The two crankshafts are the same dimension/size. the cast one makes a lower pitched sound because the grain structure is more relaxed and there fore complies with applied forced more. The forged crank sounds higher pitched because the grain stucture is tighter and stiffer, causing the same effect as say a guitar string that plays a higher pitch when tightened, and also deflects less against a specific amount of force than if it was looser.

 

[satariel666]

Re: Cran, Forged or cast?

Just curious about something.

In the past, on American V8 stuff, I could tell at a glance if the crank was cast or forged simply by looking at the "seam" or mold-die mark, which is the line that runs the length of the crank on the unfinished surface of opposite sides of the crank.

On a cast crank, the seam was just that, a narrow seam, 1/8" or so, indicating where the casting mold halves meet together,
On a forged crank it has the seam as well but it's thicker/wider , maybe 3/8"-1/2" indicating where the metal pushed out past the edges of the two halves of the dies in a hammer forge.

This vmax crank is somewhere in between, and not having eyeballed very many other (read none) motorcycle cranks I don't have any thing to compare it to.....

Is this crank Cast or Forged, and how do we know?

Thanks,

Rusty

Cast as far I know.