Diagram Looks Wrong

[AtomicSheep]

The third post has a diagram of a side view of a gantry for a CNC Router and the forces upon it.

https://www.cnczone.com/forums/diy-cnc-router-table-machines/205766-cnc-cad-posts-3.html

Question is, the force arrows look wrong to me. Shouldn't the pivot point be point A in both directions of the exerted force on the cutter (point C) along the x axis, not B? In which case fa and fb should be reversed?

 

[SwinnyGG]

I'm not a member of that forum so the image is very small/pixelated/difficult to read. You may want to ask for permission and re-post it here.

Much depends on the signs of those force vectors. The directions of the arrows are unimportant as long as the signs are corrected so that they equalize.

 

[AtomicSheep]

I'll just draw it out.

 

[SwinnyGG]

There's nothing wrong with the direction of the arrows, as long as the signs are correct.

The way they are currently drawn, if Fc is negative than Fa and Fb are positive.

Orienting forces this way can be advantageous, depending on what you're trying to accomplish.

 

[itsmoked]

Directly post your pictures using the camera/Image above.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[AtomicSheep]

Thanks, hmm time to ponder.