buildlog.net

I think some of us are talking about the focal point and some are not. I was talking about the focal point staying the same, but lasersafe1 is right that it changes the shape of the cut. If the circular beam hits the center, you get an hour glass shaped "kerf" through a thick material. If the beam is off center you still get an hour glass shape, but it is at an angle. This will affect the shape of the kerf, making the cut at an angle. There are lens aberrations etc that affect the focal point but not to the extent shown in the pictures.

it will steer the focal point

might be better said...steer the beam.

Cheers guys
I had a fiddle today and got the alignment a little better I think
Good enough to make a start on my cryptex project ( basically a combination lock with letters )



The outer rings will have letters on and can be moved to reset the combination

Anyway I have maker slide on the way and I have ordered some different optics in the hope I can make a new carriage to fit