Excellent video ,demo and explanation. I am totally new at this. Somewhat intimidated (well actually more then somewhat ) but your video has giving me more confidence.Knowing how the rollers and cutter works during the planing. Thank you again !!!!
This is great, thank you! I'm less than a year into this new hobby, and I always find it helpful to have a mental model of what's happening that lets me predict what's safe and what isn't. Your cardboard prop is perfect. :) Quick(ish) note about friction: one thing I remember from my physics classes is that friction is almost always *lower* between two objects that are moving relative to each other. (Look up "coefficient of friction" and keep an eye out for the terms "static" and "dynamic".) I don't think the calculations matter for the purposes of your explanation, but the difference means that the roller starts out pushing forward using the coefficient of *static* frction... but as soon as the cutting head starts to push the board backwards even a tiny bit harder than the roller can push it forward, the roller starts to slide relative to the wood, which means it starts to use the lower coefficient of *kinetic* friction. Just like that, suddenly the cutting head is pushing backwards a LOT harder than the roller, and out comes the board. This is the same reason a lot of cars have ABS: a skidding tire loses its grip, so the computer steps in and cuts the brakes to that tire to let it "catch up" to the road again, faster than a human can react, to stop the car faster than it would if it just laid down a long patch of rubber.
