Friction, contact area and a clamp design

[cabellos6]

I know theoretically that friction is independent of contact area. However, i have a cylinder which i want to clamp via two jaws. My thinking is that a v jaw, clamping at four points around the circumference of the cylinder would be more effective than a curved jaw design??

Thoughts would be much appreciated.

 

[gsal]

My thoughts.

Yes, friction may be independent of contact area, but the resulting force IS proportional to the contact area (pressure x area).

I am not sure what you mean by "curved" jaw design...I mean, is it rigid? is the radius of the curved jaw the same radius of the cylinder? ...what are the chances of that! If not, then what is the resulting contact between cylinder and jaw?

Do both clamps offer the exact same material in contact with the cylinder? If not, then, you are talking about 2 different friction factors, too.

Having 4 points of contact, even if the resulting force was the same, offers the advantage of more stability and keeping the cylinder oriented better so that it does not rotate in any other direction not just on its own axis. Don't you think?